Converged SDN Transport Implementation Guide (2024)

The following aligns to and uses features from Converged SDN Transport 5.0, please see the overview High Level Design document at https://xrdocs.io/design/blogs/latest-converged-sdn-transport-hld

• Hardware:

  • ASR 9000 as Centralized Provider Edge (C-PE) router
  • NCS 5500, NCS 560, and NCS 55A2 as Aggregation and Pre-Aggregation router
  • NCS 5500 as P core router
  • ASR 920, NCS 540, and NCS 5500 as Access Provider Edge (A-PE)
  • cBR-8 CMTS with 8x10GE DPIC for Remote PHY
  • Compact Remote PHY shelf with three 1x2 Remote PHY Devices (RPD)

• Software:

  • IOS-XR 7.5.2 on Cisco 8000, NCS 560, NCS 540, NCS 5500, and NCS 55A2 routers
  • IOS-XR 7.5.2 on ASR 9000 routers for non-cnBNG use
  • IOS-XR 7.4.2 on ASR 9000 routers for cnBNG use
  • IOS-XE 16.12.03 on ASR 920
  • IOS-XE 17.03.01w on cBR-8

• Key technologies

  • Transport: End-To-End Segment-Routing
  • Network Programmability: SR-TE Inter-Domain LSPs with On-Demand Next Hop
  • Network Availability: TI-LFA/Anycast-SID
  • Services: BGP-based L2 and L3 Virtual Private Network services (EVPN and L3VPN/mVPN)
  • Network Timing: G.8275.1 and G.8275.2
  • Network Assurance: 802.1ag

Devices

Access PE (A-PE) Routers

• Cisco NCS-5501-SE (IOS-XR) – A-PE7
• Cisco N540-24Z8Q2C-M (IOS-XR) - A-PE1, A-PE2, A-PE3
• Cisco N540-FH-CSR-SYS - A-PE8
• Cisco ASR-920 (IOS-XE) – A-PE9

Pre-Aggregation (PA) Routers

• Cisco NCS5501-SE (IOS-XR) – PA3, PA4

Aggregation (AG) Routers

• Cisco NCS5501-SE (IOS-XR) – AG2, AG3, AG4
• Cisco NCS 560-4 w/RSP-4E (IOS-XR) - AG1

High-scale Provider Edge Routers

• Cisco ASR9000 w/Tomahawk Line Cards (IOS-XR) – PE1, PE2
• Cisco ASR9000 w/Tomahawk and Lightspeed+ Line Cards (IOS-XR) – PE3, PE4

Area Border Routers (ABRs)

• Cisco ASR9000 (IOS-XR) – PE3, PE4
• Cisco 55A2-MOD-SE - PA2
• Cisco NCS540 - PA1

Core Routers

• Cisco 55A1-36H (36x100G) - P1,P2
• Cisco 8201-32FH - P3,P4

Service and Transport Route Reflectors (RRs)

• Cisco IOS XRv 9000 – tRR1-A, tRR1-B, sRR1-A, sRR1-B, sRR2-A, sRR2-B, sRR3-A, sRR3-B

Segment Routing Path Computation Element (SR-PCE)

• Cisco IOS XRv 9000 – SRPCE-A1-A, SRPCE-A1-B, SRPCE-A2-A, SRPCE-A2-A, SRPCE-CORE-A, SRPCE-CORE-B

• IP Addressing
  • IPv4 address plan
  • IPv6 address plan, recommend dual plane day 1
    • Plan for SRv6 in the future
• Color communities for ODN
• Segment Routing Blocks
  • SRGB (segment-routing address block)
  • Keep in mind anycast SID for ABR node pairs
  • Allocate 3 SIDs for potential future Flex-algo use
  • SRLB (segment routing local block)
    • Local significance only
    • Can be quite small and re-used on each node
• IS-IS unique instance identifiers for each domain

IOS-XR Router Configuration

Underlay Bundle interface configuration with BFD

interface Bundle-Ether100 bfd mode ietf bfd address-family ipv4 timers start 180 bfd address-family ipv4 multiplier 3 bfd address-family ipv4 destination 10.1.2.1 bfd address-family ipv4 fast-detect bfd address-family ipv4 minimum-interval 50 mtu 9216 ipv4 address 10.15.150.1 255.255.255.254 ipv4 unreachables disable load-interval 30 dampening

Underlay physical interface configuration

interface HundredGigE0/0/0/24 mtu 9216 ipv4 address 10.15.150.1 255.255.255.254 ipv4 unreachables disable load-interval 30 dampening

Performance Measurement

Interface delay metric dynamic configuration

Starting with CST 3.5 we now support end to end dynamic link delay measurements across all IOS-XR nodes. The feature in IOS-XR is called Performance Measurement and all configuration is found under the performance-measurement configuration hierarchy. There are a number of configuration options utilized when configuring performance measurement, but the below configuration will enable one-way delay measurements on physical links. The probe measurement-mode options are either one-way or two-way. One-way mode requires nodes be time synchronized to a common PTP clock, and should be used if available. In the absence of a common PTP clock source, two-way mode can be used which calculates the one-way delay using multiple timestamps at the querier and responder.

The advertisem*nt options specify when the advertisem*nts are made into the IGP. The periodic interval sets the minimum interval, with the threshold setting the difference required to advertise a new delay value. The accelerated threshold option sets a percentage change required to trigger and advertisem*nt prior to the periodic interval timer expiring. Performance measurement takes a series of measurements within each computation interval and uses this information to derive the min, max, and average link delay.

Full documentation on Performance Measurement can be found at: https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r7-5/segment-routing/configuration/guide/b-segment-routing-cg-asr9000-75x/configure-performance-measurement.html

performance-measurement interface TenGigE0/0/0/20 delay-measurement ! ! interface TenGigE0/0/0/21 delay-measurement ! ! protocol twamp-light measurement delay unauthenticated querier-dst-port 12345 ! ! ! delay-profile interfaces advertisem*nt accelerated threshold 25 ! periodic interval 120 threshold 10 ! ! probe measurement-mode two-way protocol twamp-light computation-interval 60 ! !!end

Interface delay metric static configuration

In the absence of dynamic realtime one-way latency monitoring for physical interfaces, the interface delay can be set manually. The one-way delay measurement value is used when computing SR Policy paths with the “latency” constraint type. The configured value is advertised in the IGP using extensions defined in RFC 7810, and advertised to the PCE using BGP-LS extensions. Keep in mind the delay metric value is defined in microseconds, so if you are mixing dynamic computation with static values they should be set appropriately.

performance-measurement interface TenGigE0/0/0/10 delay-measurement advertise-delay 15000 interface TenGigE0/0/0/20 delay-measurement advertise-delay 10000

SR Policy Delay Measurement Profile

Properties for SR Policy end to end measurement can be customized to set specific intervals, logging, delay thresholds, and protocol. The “default” profile will be used for all SR Policies with delay measurement enabled unless a specific profile is specified.

delay-profile sr-policy default advertisem*nt accelerated threshold 25 ! periodic interval 120 threshold 10 ! threshold-check average-delay ! ! probe tos dscp 46 ! measurement-mode two-way protocol twamp-light computation-interval 60 burst-interval 60 ! ! protocol twamp-light measurement delay unauthenticated querier-dst-port 12345

Enabling SR Policy Delay Measurement

policy srte_c_5227_ep_100.0.0.27 color 5227 end-point ipv4 100.0.0.27 candidate-paths preference 100 dynamic metric type igp ! ! ! ! performance-measurement delay-measurement

SR Policy Liveness Detection Profile

Note on platforms with HW enabled probe generation, the minimum interval is 3.3ms, on platforms with CPU probe generation, the minimum interval is 30ms (30000us).

performance-measurement liveness-profile name cst liveness-detection multiplier 3 ! probe tx-interval 30000

SR Policy with Liveness Detection Enabled

This example uses the default liveness detection profile. In this case when three probes are missed, the SR Policy will transition to a “down” state due to the “invalidation-action down” command. If this is omitted, path changes will be logged but no action will be taken.

segment-routing traffic-eng policy sr-policy-liveness color 5000 end-point ipv4 100.0.0.25 candidate-paths preference 200 dynamic pcep ! anycast-sid-inclusion ! ! constraints segments sid-algorithm 130 ! ! ! ! performance-measurement liveness-detection invalidation-action down

IOS-XR SR-MPLS Transport

Segment Routing SRGB and SRLB Definition

It’s recommended to first configure the Segment Routing Global Block (SRGB) across all nodes needing connectivity between each other. In most instances a single SRGB will be used across the entire network. In a SR MPLS deployment the SRGB and SRLB correspond to the label blocks allocated to SR. IOS-XR has a maximum configurable SRGB limit of 512,000 labels, however please consult platform-specific documentation for maximum values. The SRLB corresponds to the labels allocated for SIDs local to the node, such as Adjacency-SIDs. It is recommended to configure the same SRLB block across all nodes. The SRLB must not overlap with the SRGB. The SRGB and SRLB are configured in IOS-XR with the following configuration:

segment-routing global-block 16000 23999 local-block 15000 15999

IGP protocol (ISIS) and Segment Routing MPLS configuration

The following section documents the configuration without Flex-Algo, Flex-Algo configuration is found in the Flex-Algo configuration section.

Key chain global configuration for IS-IS authentication

key chain ISIS-KEY key 1 accept-lifetime 00:00:00 january 01 2018 infinite key-string password 00071A150754 send-lifetime 00:00:00 january 01 2018 infinite cryptographic-algorithm HMAC-MD5

IS-IS router configuration

All routers, except Area Border Routers (ABRs), are part of one IGP domain and L2 area (ISIS-ACCESS or ISIS-CORE). Area border routers
run two IGP IS-IS processes (ISIS-ACCESS and ISIS-CORE). Note that Loopback0 is part of both IGP processes.

router isis ISIS-ACCESS set-overload-bit on-startup 360 is-type level-2-only net 49.0001.0101.0000.0110.00 nsr distribute link-state nsf cisco log adjacency changes lsp-gen-interval maximum-wait 5000 initial-wait 5 secondary-wait 100 lsp-refresh-interval 65000 max-lsp-lifetime 65535 lsp-password keychain ISIS-KEY address-family ipv4 unicast metric-style wide advertise link attributes spf-interval maximum-wait 1000 initial-wait 5 secondary-wait 100 segment-routing mpls spf prefix-priority high tag 1000 maximum-redistributed-prefixes 100 level 2 ! address-family ipv6 unicast metric-style wide spf-interval maximum-wait 5000 initial-wait 50 secondary-wait 200 maximum-redistributed-prefixes 100 level 2

Note: ABR Loopback 0 on domain boundary is part of both IGP processes together with same “prefix-sid absolute” value

Note: The prefix SID can be configured as either absolute or index. The index configuration is required for interop with nodes using a different SRGB.

IS-IS Loopback and node SID configuration

 interface Loopback0 ipv4 address 100.0.1.50 255.255.255.255 address-family ipv4 unicast prefix-sid absolute 16150 tag 1000 

IS-IS Physical and Bundle interface configuration with BFD

interface HundredGigE0/0/0/20/0 circuit-type level-2-only bfd minimum-interval 5 bfd multiplier 5 bfd fast-detect ipv4 point-to-point address-family ipv4 unicast fast-reroute per-prefix fast-reroute per-prefix ti-lfa metric 10

MPLS-TE Configuration

Enabling the use of Segment Routing Traffic Engineering requires first configuring basic MPLS TE so the router Traffic Engineering Database (TED) is populated with the proper TE attributes. The configuration requires no

mpls traffic-eng

Unnumbered Interfaces

IS-IS and Segment Routing/SR-TE utilized in the Converged SDN Transport design supports using unnumbered interfaces. SR-PCE used to compute inter-domain SR-TE paths also supports the use of unnumbered interfaces. In the topology database each interface is uniquely identified by a combination of router ID and SNMP IfIndex value.

Unnumbered interface configuration

interface TenGigE0/0/0/2 description to-AG2 mtu 9216 ptp profile My-Slave port state slave-only local-priority 10 ! service-policy input core-ingress-classifier service-policy output core-egress-exp-marking ipv4 point-to-point ipv4 unnumbered Loopback0  frequency synchronization selection input priority 10 wait-to-restore 1 !!

Unnumbered Interface IS-IS Database

The IS-IS database will reference the node SNMP IfIndex value

Metric: 10 IS-Extended A-PE1.00  Local Interface ID: 1075, Remote Interface ID: 40  Affinity: 0x00000000 Physical BW: 10000000 kbits/sec Reservable Global pool BW: 0 kbits/sec Global Pool BW Unreserved: [0]: 0 kbits/sec [1]: 0 kbits/sec [2]: 0 kbits/sec [3]: 0 kbits/sec [4]: 0 kbits/sec [5]: 0 kbits/sec [6]: 0 kbits/sec [7]: 0 kbits/sec Admin. Weight: 90 Ext Admin Group: Length: 32 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 0x00000000 Link Average Delay: 1 us Link Min/Max Delay: 1/1 us Link Delay Variation: 0 us Link Maximum SID Depth: Label Imposition: 12 ADJ-SID: F:0 B:1 V:1 L:1 S:0 P:0 weight:0 Adjacency-sid:24406 ADJ-SID: F:0 B:0 V:1 L:1 S:0 P:0 weight:0 Adjacency-sid:24407

Anycast SID ABR node configuration

Anycast SIDs are SIDs existing on two more ABR nodes to offer a redundant fault tolerant path for traffic between Access PEs and remote PE devices. In CST 3.5 and above, anycast SID paths can either be manually configured on the head-end or computed by the SR-PCE. When SR-PCE computes a path it will inspect the topology database to ensure the next SID in the computed segment list is reachable from all anycast nodes. If not, the anycast SID will not be used. The same IP address and prefix-sid must be configured on all shared anycast nodes, with the n-flag clear option set. Note when anycast SID path computation is used with SR-PCE, only IGP metrics are supported.

IS-IS Configuration for Anycast SID

router isis ACCESS interface Loopback100 ipv4 address 100.100.100.1 255.255.255.255 address-family ipv4 unicast prefix-sid absolute 16150 n-flag clear tag 1000 

Conditional IGP Loopback advertisem*nt While not the only use case for conditional advertisem*nt, it is a required component when using anycast SIDs with static segment list. Conditional advertisem*nt will not advertise the Loopback interface if certain routes are not found in the RIB. If the anycast Loopback is withdrawn, the segment list will be considered invalid on the head-end node. The conditional prefixes should be all or a subset of prefixes from the adjacent IGP domain.

route-policy check if rib-has-route in async remote-prefixes pass endif end-policyprefix-set remote-prefixes 100.0.2.52, 100.0.2.53

router isis ACCESS interface Loopback100 address-family ipv4 unicast advertise prefix route-policy check

IS-IS logical interface configuration with TI-LFA

It is recommended to use manual adjacency SIDs. A protected SID is eligible for backup path computation, meaning if a packet ingresses the node with the label a backup path will be provided in case of a link failure. In the case of having multiple adjacencies between the same two nodes, use the same adjacency-sid on each link. Unnumbered interfaces are configured using the same configuration.

 interface TenGigE0/0/0/10 point-to-point hello-password keychain ISIS-KEY address-family ipv4 unicast fast-reroute per-prefix fast-reroute per-prefix ti-lfa adjacency-sid absolute 15002 protected metric 100 ! address-family ipv6 unicast fast-reroute per-prefix fast-reroute per-prefix ti-lfa metric 100 

Segment Routing Data Plane Monitoring

In CST 3.5 we introduce SR DPM across all IOS-XR platforms. SR DPM uses MPLS OAM mechanisms along with specific SID lists in order to exercise the dataplane of the originating node, detecting blackholes typically difficult to diagnose. SR DPM ensures the nodes SR-MPLS forwarding plane is valid without a drop in traffic towards adjacent nodes and other nodes in the same IGP domain. SR DPM is a proactive approach to blackhole detection and mitigation.

SR DPM first performs interface adjacency checks by sending an MPLS OAM packet to adjacent nodes using the interface adjacency SID and its own node SID in the SID list. This ensures the adjacent node is sending traffic back to the node correctly.

Once this connectivity is verified, SR DPM will then test forwarding to all other node SIDs in the IGP domain across each adjacency. This is done by crafting a MPLS OAM packet with SID list {Adj-SID, Target Node SID} with TTL=2. The packet is sent to the adjacent node, back to the SR DPM testing node, and then onto the target node via SR-MPLS forwarding. The downstream node towards the target node will receive the packet with TTL=0 and send an MPLS OAM response to the SR DPM originating node. This communicates valid forwarding across the originating node towards the target node.

It is recommended to enable SR DPM on all CST IOS-XR nodes.

SR Data Plane Monitoring Configuration

mpls oam dpm pps 10 interval 60 (minutes) 

MPLS Segment Routing Traffic Engineering (SR-TE) configuration

The following configuration is done at the global ISIS configuration level and should be performed for all IOS-XR nodes.

router isis ACCESS address-family ipv4 unicast mpls traffic-eng level-2-only mpls traffic-eng router-id Loopback0

MPLS Segment Routing Traffic Engineering (SR-TE) TE metric configuration

The TE metric is used when computing SR Policy paths with the “te” or “latency” constraint type. The TE metric is carried as a TLV within the TE opaque LSA distributed across the IGP area and to the PCE via BGP-LS.
The TE metric is used in the CST 5G Transport use case. If no TE metric is defined the local CSPF or PCE will utilize the IGP metric.

segment-routing traffic-eng interface TenGigE0/0/0/6 metric 1000

IOS-XR SR Flexible Algorithm Configuration

Segment Routing Flexible Algorithm offers a way to to easily define multiple logical network topologies satisfying a specific network constraint. Flex-Algo definitions must first be configured in each IGP domain on all nodes participating in Flex-Algo. By default, all nodes participate in Algorithm 0, mapping to “use lowest IGP metric” path computation. In the CST design, ABR nodes must have Flex-Algo definitions in both IS-IS instances if an inter-domain path is required.

Flex-Algo IS-IS Definition

Each Flex-Algo is defined on the nodes participating in the Flex-Algo. In this configuration IS-IS is configured to advertise the definition network wide. This is not required on each node in the domain, only a single node needs to advertise the definition, but there is no downside to having each node advertise the definition. In this case we are also defining a link affinity to be used in the 131 Flex-Algo. The same affinity-map must be used on all nodes in the IGP domain. The link affinity is configured under specific interfaces in the IS-IS interface configuration as shown with interface TenGigE0/0/0/20 below. The configuration for 131 is set to exclude links matching the “red” affinity, so any path utilizing Flex-Algo 131 as a constraint will not utilize the TenGigE0/0/0/20 path. The Flex-Algo link affinity is applied to both local and remote interfaces matching the affinity.

Also note non-Flex-Algo configuration can utilize link affinities, which are defined under segment-routing->traffic-engineering->interface->affinity.

As of CST 4.0, delay is the only metric-type supported. Utilizing the delay metric-type for a Flex-Algo will ensure a path will utilize only the lowest delay path, even if a single destination SID is referenced in the SR-TE path.

router isis ACCESS affinity-map red bit-position 0 flex-algo 128 advertise-definition ! flex-algo 129 advertise-definition ! flex-algo 130 metric-type delay advertise-definition ! flex-algo 131 advertise-definition affinity exclude-any red ! ! interface TenGigE0/0/0/20 affinity flex-algo red

Flex-Algo Node SID Configuration

Flex-Algo works by allocating a globally unique node SID referencing the algorithm on each node participating in the Flex-Algo topology. This requires additional Node SID configuration on the Loopback0 interface for each router. The following is an example for a node participating in four different Flex-Algo domains in addition to the default Algo 0 domain, covered by the base Node SID configuration. Each SID belongs to the same global SRGB.

router isis ACCESS interface Loopback0 address-family ipv4 unicast prefix-sid index 150 prefix-sid algorithm 128 absolute 18003 prefix-sid algorithm 129 absolute 19003 prefix-sid algorithm 130 absolute 20003 prefix-sid algorithm 131 absolute 21003

If one inspects the IS-IS database for the nodes, you will see the Flex-Algo SID entries.

RP/0/RP0/CPU0:NCS540-A-PE3#show isis database NCS540-A-PE3.00-00 verbose Router Cap: 100.0.1.50 D:0 S:0 Segment Routing: I:1 V:0, SRGB Base: 16000 Range: 8000 SR Local Block: Base: 15000 Range: 1000 Node Maximum SID Depth: Label Imposition: 12 SR Algorithm: Algorithm: 0 Algorithm: 1 Algorithm: 128 Algorithm: 129 Algorithm: 130 Algorithm: 131 Flex-Algo Definition: Algorithm: 128 Metric-Type: 0 Alg-type: 0 Priority: 128 Flex-Algo Definition: Algorithm: 129 Metric-Type: 0 Alg-type: 0 Priority: 128 Flex-Algo Definition: Algorithm: 130 Metric-Type: 1 Alg-type: 0 Priority: 128 Flex-Algo Definition: Algorithm: 131 Metric-Type: 0 Alg-type: 0 Priority: 128 Flex-Algo Exclude-Any Ext Admin Group: 0x00000001

IOS-XE Nodes - SR-MPLS Transport

Segment Routing MPLS configuration

mpls label range 6001 32767 static 16 6000segment-routing mpls ! set-attributes address-family ipv4 sr-label-preferred exit-address-family ! global-block 16000 24999 !

Prefix-SID assignment to loopback 0 configuration

 connected-prefix-sid-map address-family ipv4 100.0.1.51/32 index 151 range 1 exit-address-family !

Basic IGP protocol (ISIS) with Segment Routing MPLS configuration

key chain ISIS-KEY key 1 key-string cisco accept-lifetime 00:00:00 Jan 1 2018 infinite send-lifetime 00:00:00 Jan 1 2018 infinite!router isis ACCESS net 49.0001.0102.0000.0254.00 is-type level-2-only authentication mode md5 authentication key-chain ISIS-KEY metric-style wide fast-flood 10 set-overload-bit on-startup 120 max-lsp-lifetime 65535 lsp-refresh-interval 65000 spf-interval 5 50 200 prc-interval 5 50 200 lsp-gen-interval 5 5 200 log-adjacency-changes segment-routing mpls segment-routing prefix-sid-map advertise-local

TI-LFA FRR configuration

 fast-reroute per-prefix level-2 all fast-reroute ti-lfa level-2 microloop avoidance protected!interface Loopback0 ip address 100.0.1.51 255.255.255.255 ip router isis ACCESS isis circuit-type level-2-onlyend

IS-IS and MPLS interface configuration

interface TenGigabitEthernet0/0/12 mtu 9216 ip address 10.117.151.1 255.255.255.254 ip router isis ACCESS mpls ip isis circuit-type level-2-only isis network point-to-point isis metric 100end

MPLS Segment Routing Traffic Engineering (SR-TE)

router isis ACCESS mpls traffic-eng router-id Loopback0 mpls traffic-eng level-2

Area Border Routers (ABRs) IPv4/IPv6 route distribution using BGP

The ABR nodes must provide IP reachability for RRs, SR-PCEs and NSO between ISIS-ACCESS and ISIS-CORE IGP domains. One use case is SR Tree-SID, which requires all nodes have a PCEP session to a single SR-PCE.

The recommended method to achieve reachability to nodes in the Core domain from access domain routers is to utilize BGP to advertise the Loopback addresses of specific nodes to the ABR nodes, and use either BGP to IGP redistribution or IPv4/IPv6 Unicast BGP between ABR and access nodes to distribute those routes. If unicast BGP is used, the ABR nodes will act as inline Route Reflectors.

Reachability to the access routers from the core routes is provided by advertising access domain aggregate routes from each access domain via BGP to core nodes requiring them. If the core element such as SR-PCE is a router, SR-MPLS and BGP can enabled, with the ABRs advertising the aggregates directly. If the element is not a router, then the router it is connected to will receive and advertise BGP prefixes to establish end to end connectivity.

The following is an example from one ABR node and one SR-PCE node.

Core SR-PCE BGP Configuration

The following configuration is for SR-PCE with Loopback 101.0.0.100. 101.0.0.3 and 101.0.0.4 are ABRs for one access domain, 101.0.1.1 and 101.0.1.2 the other. The optional route policies are used as a strict check to make sure only the proper routes are being received.

route-policy access1-in if destination in (101.0.1.0/24) then pass else drop endifend-policy!route-policy access2-in if destination in (101.0.2.0/24) then pass else drop endifend-policyrouter bgp 100 nsr bgp router-id 101.0.0.100 bgp redistribute-internal bgp graceful-restart nexthop validation color-extcomm sr-policy nexthop validation color-extcomm disable ibgp policy out enforce-modifications address-family ipv4 unicast network 101.0.0.100/32 ! neighbor 101.0.0.3 remote-as 100 update-source Loopback0 address-family ipv4 unicast route-policy access1-in in ! ! neighbor 101.0.0.4 remote-as 100 update-source Loopback0 address-family ipv4 unicast route-policy access1-in in ! ! neighbor 101.0.1.1 remote-as 100 update-source Loopback0 address-family ipv4 unicast route-policy access2-in in ! ! neighbor 101.0.1.2 remote-as 100 update-source Loopback0 address-family ipv4 unicast route-policy access2-in in ! !

ABR BGP Configuration

In this example the ABR node advertises the aggregate 100.0.1.0/24 covering A-PE loopback addresses in the Access-1 IGP domain to the core SR-PCE node. It uses the IPv4 unicast AFI to advertise the SR-PCE Loopback prefix to the A-PE nodes. Route policies are used to restrict the prefixes advertised in both directions.

router staticaddress-family ipv4 unicast 100.0.1.0/24 Null0prefix-set ACCESS-PE-PREFIX 100.0.1.0/24end-setprefix-set SRPCE-PREFIX 100.0.0.100/32end-setroute-policy ABR-to-SRPCE if destination in ACCESS-PE-PREFIX then pass else drop endifend-policy!route-policy ABR-to-APE if destination in SRPCE-PREFIX then pass else drop endifend-policy!router bgp 100 nsr bgp router-id 101.0.0.3 bgp redistribute-internal bgp graceful-restart nexthop validation color-extcomm sr-policy nexthop validation color-extcomm disable ibgp policy out enforce-modifications address-family ipv4 unicast network 100.0.1.0/24 ! address-family ipv6 unicast ! neighbor-group BGP-APE remote-as 100 update-source Loopback0 ! address-family ipv4 unicast route-reflector-client route-policy ABR-to-APE out next-hop-self ! address-family ipv6 unicast route-reflector-client next-hop-self ! ! neighbor 101.0.2.52 use neighbor-group BGP-APE ! neighbor 101.0.2.53 use neighbor-group BGP-APE ! neighbor 101.0.0.100 description SR-PCE remote-as 100 update-source Loopback0 address-family ipv4 unicast route-policy ABR-to-SRPCE out next-hop-self ! !

Deprecated Area Border Routers (ABRs) IGP-ISIS Redistribution configuration (IOS-XR)

Note the following is for historical reference and has been deprecated, IGP redistribution is not recommended for production deployments

The ABR nodes must provide IP reachability for RRs, SR-PCEs and NSO between ISIS-ACCESS and ISIS-CORE IGP domains. This is done by IP prefix redistribution. The ABR nodes have static hold-down routes for the block of IP space used in each domain across the network, those static routes are then redistributed into the domains using the redistribute static command with a route-policy. The distance command is used to ensure redistributed routes are not preferred over local IS-IS routes on the opposite ABR. The distance command must be applied to both ABR nodes.

router staticaddress-family ipv4 unicast 100.0.0.0/24 Null0 100.0.1.0/24 Null0 100.1.0.0/24 Null0 100.1.1.0/24 Null0prefix-set ACCESS-PCE_SvRR-LOOPBACKS 100.0.1.0/24, 100.1.1.0/24end-setprefix-set RR-LOOPBACKS 100.0.0.0/24, 100.1.0.0/24end-set

Redistribute Core SvRR and TvRR loopback into Access domain

route-policy CORE-TO-ACCESS1 if destination in RR-LOOPBACKS then pass else drop endifend-policy!router isis ACCESS address-family ipv4 unicast distance 254 0.0.0.0/0 RR-LOOPBACKS redistribute static route-policy CORE-TO-ACCESS1 

Redistribute Access SR-PCE and SvRR loopbacks into CORE domain

route-policy ACCESS1-TO-CORE if destination in ACCESS-PCE_SvRR-LOOPBACKS then pass else drop endif end-policy ! router isis CORE address-family ipv4 unicast distance 254 0.0.0.0/0 ACCESS-PCE_SvRR-LOOPBACKS redistribute static route-policy CORE-TO-ACCESS1

Multicast transport using mLDP

Overview

This portion of the implementation guide instructs the user how to configure mLDP end to end across the multi-domain network. Multicast service examples are given in the “Services” section of the implementation guide.

mLDP core configuration

In order to use mLDP across the Converged SDN Transport network LDP must first be enabled. There are two mechanisms to enable LDP on physical interfaces across the network, LDP auto-configuration or manually under the MPLS LDP configuration context. The capabilities statement will ensure LDP unicast FECs are not advertised, only mLDP FECs. Recursive forwarding is required in a multi-domain network. mLDP must be enabled on all participating A-PE, PE, AG, PA, and P routers.

LDP base configuration with defined interfaces

mpls ldp capabilities sac mldp-only mldp logging notifications address-family ipv4 make-before-break delay 30 forwarding recursive recursive-fec ! ! router-id 100.0.2.53 session protection address-family ipv4 ! interface TenGigE0/0/0/6 ! interface TenGigE0/0/0/7

LDP auto-configuration

LDP can automatically be enabled on all IS-IS interfaces with the following configuration in the IS-IS configuration. It is recommended to do this only after configuring all MPLS LDP properties.

router isis ACCESS address-family ipv4 unicast segment-routing mpls sr-prefer mpls ldp auto-config

G.8275.1 and G.8275.2 PTP (1588v2) timing configuration

Summary

This section contains the base configurations used for both G.8275.1 and G.8275.2 timing. Please see the CST HLD for an overview on timing in general. G.8275.1 is the preferred method for end to end timing if possible since it provides the most accurate clock and has no limitations on interface type used for PTP peers. G.8275.1 to G.8275.2 interworking can be used on edge nodes to provide timing to devices requiring G.8275.2.

Enable frequency synchronization

In order to lock the internal oscillator to a PTP source, frequency synchronization must first be enabled globally.

frequency synchronization quality itu-t option 1 clock-interface timing-mode system log selection changes!

Optional Synchronous Ethernet configuration (PTP hybrid mode)

If the end-to-end devices support SyncE it should be enabled. SyncE will allow much faster frequency sync and maintain integrity for long periods of time during holdover events. Using SyncE for frequency and PTP for phase is known as “Hybrid” mode. A lower priority is used on the SyncE input (50 for SyncE vs. 100 for PTP).

interface TenGigE0/0/0/10 frequency synchronization selection input priority 50 !!

PTP G.8275.2 global timing configuration

As of CST 3.0, IOS-XR supports a single PTP timing profile and single clock type in the global PTP configuration. The clock domain should follow the ITU-T guidelines for specific profiles using a domain >44 for G.8275.2 clocks.

ptp clock domain 60 profile g.8275.2 clock-type T-BC ! frequency priority 100 time-of-day priority 50 log servo events best-master-clock changes !

PTP G.8275.2 interface profile definitions

It is recommended to use “profiles” defined globally which are then applied to interfaces participating in timing. This helps minimize per-interface timing configuration. It is also recommended to define different profiles for “master” and “slave” interfaces.

IPv4 G.8275.2 master profile

The master profile is assigned to interfaces for which the router is acting as a boundary clock

ptp profile g82752_master_v4 transport ipv4 port state master-only sync frequency 16 clock operation one-step <-- Note the NCS series should be configured with one-step, ASR9000 with two-step announce timeout 5 announce interval 1 unicast-grant invalid-request deny delay-request frequency 16 !!

IPv6 G.8275.2 master profile

The master profile is assigned to interfaces for which the router is acting as a boundary clock

ptp profile g82752_master_v6 transport ipv6 port state master-only sync frequency 16 clock operation one-step announce timeout 10 announce interval 1 unicast-grant invalid-request deny delay-request frequency 16 !!

IPv4 G.8275.2 slave profile

The slave profile is assigned to interfaces for which the router is acting as a slave to another master clock

ptp profile g82752_master_v4 transport ipv4 port state slave-only sync frequency 16 clock operation one-step <-- Note the NCS series should be configured with one-step, ASR9000 with two-step announce timeout 10 announce interval 1 unicast-grant invalid-request deny delay-request frequency 16 !!

IPv6 G.8275.2 slave profile

The slave profile is assigned to interfaces for which the router is acting as a slave to another master clock

ptp profile g82752_master_v6 transport ipv6 port state slave-only sync frequency 16 clock operation one-step <-- Note the NCS series should be configured with one-step, ASR9000 with two-step announce timeout 10 announce interval 1 unicast-grant invalid-request deny delay-request frequency 16 !!

PTP G.8275.1 global timing configuration

As of CST 3.0, IOS-XR supports a single PTP timing profile and single clock type in the global PTP configuration. The clock domain should follow the ITU-T guidelines for specific profiles using a domain <44 for G.8275.1 clocks.

ptpclock domain 24 operation one-step Use one-step for NCS series, two-step for ASR 9000 physical-layer-frequency frequency priority 100 profile g.8275.1 clock-type T-BClog servo events best-master-clock changes

IPv6 G.8275.1 slave profile

The slave profile is assigned to interfaces for which the router is acting as a slave to another master clock

ptp profile g82751_slave port state slave-only clock operation one-step <-- Note the NCS series should be configured with one-step, ASR9000 with two-step announce timeout 10 announce interval 1 delay-request frequency 16 multicast transport ethernet !!

IPv6 G.8275.1 master profile

The master profile is assigned to interfaces for which the router is acting as a master to slave devices

ptp profile g82751_slave port state master-only clock operation one-step <-- Note the NCS series should be configured with one-step, ASR9000 with two-step sync frequency 16 announce timeout 10 announce interval 1 delay-request frequency 16 multicast transport ethernet !!

Application of PTP profile to physical interface

Note: In CST 3.0 PTP may only be enabled on physical interfaces. G.8275.1 operates at L2 and supports PTP across Bundle member links and interfaces part of a bridge domain. G.8275.2 operates at L3 and does not support Bundle interfaces.

G.8275.2 interface configuration

This example is of a slave device using a master of 2405:10:23:253::0.

interface TenGigE0/0/0/6 ptp profile g82752_slave_v6 master ipv6 2405:10:23:253:: ! !

G.8275.1 interface configuration

interface TenGigE0/0/0/6 ptp profile g82751_slave ! !

G.8275.1 and G.8275.2 Multi-Profile and Interworking

In CST 4.0 and IOS-XR 7.2.2 PTP Multi-Profile is supported, along with the ability to interwork between G.8275.1 and G.8275.2 on the same router. This allows a node to run one timing profile to its upstream GM peer and supply a timing reference to downstream peers using different profiles. It is recommended to use G.8275.1 as the primary profile across the network, and G.8275.2 to peers who only support the G.8275.2 profile, such as Remote PHY Devices.

The interworking feature is enabled on the client interface which has a different profile from the primary node profile. The domain must be specified along with the interop mode.

G.8275.1 Primary to G.8275.2 Configuration

interface TenGigE0/0/0/5 ptp  interop g.8275.2 domain 60  ! transport ipv4 port state master-only 

G.8275.2 Primary to G.8275.1 Configuration

interface TenGigE0/0/0/5 ptp  interop g.8275.1 domain 24  ! transport ethernet port state master-only 

Segment Routing Path Computation Element (SR-PCE) configuration

router static address-family ipv4 unicast 0.0.0.0/1 Null0router bgp 100 nsr bgp router-id 100.0.0.100 bgp graceful-restart graceful-reset bgp graceful-restart ibgp policy out enforce-modifications address-family link-state link-state ! neighbor-group TvRR remote-as 100 update-source Loopback0 address-family link-state link-state ! ! neighbor 100.0.0.10 use neighbor-group TvRR ! neighbor 100.1.0.10 use neighbor-group TvRR !!pce address ipv4 100.100.100.1 rest user rest_user password encrypted 00141215174C04140B ! authentication basic ! state-sync ipv4 100.100.100.2 peer-filter ipv4 access-list pe-routers!

BGP - Services (sRR) and Transport (tRR) route reflector configuration

Services Route Reflector (sRR) configuration

In the CST validation a sRR is used to reflect all service routes. In a production network each service could be allocated its own sRR based on resiliency and scale demands. In CST 5.0 (XR 7.5.2) and higher versions we will utilize the BGP soft next-hop validation feature to accept service prefixes without a BGP next-hop residing in the RIB.

router bgp 100 nsr bgp router-id 100.0.0.200 bgp graceful-restart nexthop validation color-extcomm disable ibgp policy out enforce-modifications address-family vpnv4 unicast nexthop trigger-delay critical 10 additional-paths receive additional-paths send ! address-family vpnv6 unicast nexthop trigger-delay critical 10 additional-paths receive additional-paths send retain route-target all ! address-family l2vpn evpn additional-paths receive additional-paths send ! address-family ipv4 mvpn nexthop trigger-delay critical 10 soft-reconfiguration inbound always ! address-family ipv6 mvpn nexthop trigger-delay critical 10 soft-reconfiguration inbound always ! neighbor-group SvRR-Client remote-as 100 bfd fast-detect bfd minimum-interval 3 update-source Loopback0 address-family l2vpn evpn route-reflector-client ! address-family vpnv4 unicast route-reflector-client ! address-family vpnv6 unicast route-reflector-client ! address-family ipv4 mvpn route-reflector-client ! address-family ipv6 mvpn route-reflector-client ! ! neighbor 100.0.0.1 use neighbor-group SvRR-Client !!

Transport Route Reflector (tRR) configuration

In CST 5.0 (XR 7.5.2) and higher versions we will utilize the BGP soft next-hop validation feature to accept BGP-LS prefixes without a BGP next-hop residing in the RIB.

router bgp 100 nsr bgp router-id 100.0.0.10 bgp graceful-restart nexthop validation color-extcomm disable ibgp policy out enforce-modifications address-family link-state link-state additional-paths receive additional-paths send ! neighbor-group RRC remote-as 100 update-source Loopback0 address-family link-state link-state route-reflector-client ! ! neighbor 100.0.0.1 use neighbor-group RRC ! neighbor 100.0.0.2 use neighbor-group RRC!

BGP – Provider Edge Routers (A-PEx and PEx) to service RR

Each PE router is configured with BGP sessions to service route-reflectors for advertising VPN service routes across the inter-domain network.

IOS-XR configuration

In CST 5.0 (XR 7.5.2) and higher versions we will utilize the BGP soft next-hop validation feature. PE nodes will use the computed ODN SR-TE Policy as a validation criteria for the BGP path. If a SR-TE Policy can be computed either locally or by SR-PCE, the path will be active, otherwise the path will not be installed.

router bgp 100 nsr bgp router-id 100.0.1.50 bgp graceful-restart graceful-reset bgp graceful-restart nexthop validation color-extcomm sr-policy ibgp policy out enforce-modifications address-family vpnv4 unicast ! address-family vpnv6 unicast ! address-family ipv4 mvpn ! address-family ipv6 mvpn ! address-family l2vpn evpn ! neighbor-group SvRR remote-as 100 bfd fast-detect bfd minimum-interval 3 update-source Loopback0 address-family vpnv4 unicast soft-reconfiguration inbound always ! address-family vpnv6 unicast soft-reconfiguration inbound always ! address-family ipv4 mvpn soft-reconfiguration inbound always ! address-family ipv6 mvpn soft-reconfiguration inbound always ! address-family l2vpn evpn soft-reconfiguration inbound always ! ! neighbor 100.0.1.201 use neighbor-group SvRR ! ! 

IOS-XE configuration

router bgp 100 bgp router-id 100.0.1.51 bgp log-neighbor-changes no bgp default ipv4-unicast neighbor SvRR peer-group neighbor SvRR remote-as 100 neighbor SvRR update-source Loopback0 neighbor 100.0.1.201 peer-group SvRR ! address-family ipv4 exit-address-family ! address-family vpnv4 neighbor SvRR send-community both neighbor SvRR next-hop-self neighbor 100.0.1.201 activate exit-address-family ! address-family l2vpn evpn neighbor SvRR send-community both neighbor SvRR next-hop-self neighbor 100.0.1.201 activate exit-address-family !

BGP-LU co-existence BGP configuration

CST 3.0 introduced co-existence between services using BGP-LU and SR endpoints. If you are using SR and BGP-LU within the same domain it requires using BGP-SR in order to resolve prefixes correctly on the each ABR. BGP-SR uses a new BGP attribute attached to the BGP-LU prefix to convey the SR prefix-sid index end to end across the network. Using the same prefix-sid index both within the SR-MPLS IGP domain and across the BGP-LU network simplifies the network from an operational perspective since the path to an end node can always be identified by that SID.

It is recommended to enable the BGP-SR configuration when enabling SR on the PE node. See the PE configuration below for an example of this configuration.

Segment Routing Global Block Configuration

The BGP process must know about the SRGB in order to properly allocate local BGP-SR labels when receiving a BGP-LU prefix with a BGP-SR index community. This is done via the following configuration. If a SRGB is defined under the IGP it must match the global SRGB value. The IGP will inherit this SRGB value if none is previously defined.

segment-routing global-block 32000 64000 !! 

Boundary node configuration

The following configuration is necessary on all domain boundary nodes. Note the ibgp policy out enforce-modifications command is required to change the next-hop on reflected IBGP routes.

router bgp 100 ibgp policy out enforce-modifications neighbor-group BGP-LU-PE remote-as 100 update-source Loopback0 address-family ipv4 labeled-unicast soft-reconfiguration inbound always route-reflector-client next-hop-self ! ! neighbor-group BGP-LU-BORDER remote-as 100 update-source Loopback0 address-family ipv4 labeled-unicast soft-reconfiguration inbound always route-reflector-client next-hop-self ! ! neighbor 100.0.2.53 use neighbor-group BGP-LU-PE ! neighbor 100.0.2.52 use neighbor-group BGP-LU-PE ! neighbor 100.0.0.1 use neighbor-group BGP-LU-BORDER ! neighbor 100.0.0.2 use neighbor-group BGP-LU-BORDER ! ! 

PE node configuration

The following configuration is necessary on all domain PE nodes participating in BGP-LU/BGP-SR. The label-index set must match the index of the Loopback addresses being advertised into BGP. This example shows a single Loopback address being advertised into BGP.

route-policy LOOPBACK-INTO-BGP-LU($SID-LOOPBACK0) set label-index $SID-LOOPBACK0 set aigp-metric igp-costend-policy!router bgp 100 address-family ipv4 unicast network 100.0.2.53/32 route-policy LOOPBACK-INTO-BGP-LU(153) ! neighbor-group BGP-LU-BORDER remote-as 100 update-source Loopback0 address-family ipv4 labeled-unicast ! ! neighbor 100.0.0.3 use neighbor-group BGP-LU-BORDER ! neighbor 100.0.0.4 use neighbor-group BGP-LU-BORDER !

Area Border Routers (ABRs) IGP topology distribution

Next network diagram: “BGP-LS Topology Distribution” shows how Area Border Routers (ABRs) distribute IGP network topology from ISIS ACCESS and ISIS CORE to Transport Route-Reflectors (tRRs). tRRs then reflect topology to Segment Routing Path Computation Element (SR-PCEs). Each SR-PCE has full visibility of the entire inter-domain network.

Note: Each IS-IS process in the network requires a unique instance-id to identify itself to the PCE.

Figure 5: BGP-LS Topology Distribution

router isis ACCESS **distribute link-state instance-id 101** net 49.0001.0101.0000.0001.00 address-family ipv4 unicast mpls traffic-eng router-id Loopback0 !! router isis CORE **distribute link-state instance-id 100** net 49.0001.0100.0000.0001.00 address-family ipv4 unicast mpls traffic-eng router-id Loopback0 !! router bgp 100 **address-family link-state link-state** ! neighbor-group TvRR remote-as 100 update-source Loopback0 address-family link-state link-state ! neighbor 100.0.0.10 use neighbor-group TvRR ! neighbor 100.1.0.10 use neighbor-group TvRR !

Segment Routing Traffic Engineering (SR-TE) and Services Integration

This section shows how to integrate Traffic Engineering (SR-TE) with services. ODN is configured by first defining a global ODN color associated with specific SR Policy constraints. The color and BGP next-hop address on the service route will be used to dynamically instantiate a SR Policy to the remote VPN endpoint.

On Demand Next-Hop (ODN) configuration – IOS-XR

The following is an example of the elements needed in addition to the base SR configuration. An on-demand policy must be created matching the a color to set the attributes of the SR-TE Policy. ODN does not require PCEP, but for inter-domain path computation is required.

On-Demand Route Policies

Coloring service routes requires routing policies to set a specific extended community on those routes and apply the policy during the import and export of the routes. Coloring can be performed in a policy at the BGP neighbor level or at the individual service level. The following example shows global level coloring, however it is recommended for granularity and ease of management to color routes at the service level.

In CST 5.0 (XR 7.5.2) or higher ODN policies can be applied on import or export for L3VPN prefixes. EVPN Type1/3 prefixes must be applied on export.

Community Set and Routing Policy Definition

extcommunity-set opaque BLUE 100end-setroute-policy ODN set extcommunity color BLUEend-policyroute-policy c2001 if evpn-route-type is 1 then set extcommunity color c2001 elseif evpn-route-type is 3 then set extcommunity color c2002 endifend-policy

Neighbor level application

router bgp 100 neighbor-group SVRR-EVPN address-family l2vpn evpn route-policy ODN_EVPN out

Service level application

vrf ODN-L3VPN rd 100:1 address-family ipv4 unicast import route-target 100:1 ! export route-target export route-policy ODN-L3VPN-OUT 100:1!evpn evi 2001 bgp route-policy export c2001

segment-routing traffic-eng logging policy status ! on-demand color 100 dynamic pce ! metric type igp ! ! ! pcc source-address ipv4 100.0.1.50 pce address ipv4 100.0.1.101 ! pce address ipv4 100.1.1.101

On Demand Next-Hop (ODN) configuration – IOS-XE

mpls traffic-eng tunnelsmpls traffic-eng pcc peer 100.0.1.101 source 100.0.1.51mpls traffic-eng pcc peer 100.0.1.111 source 100.0.1.51mpls traffic-eng pcc report-allmpls traffic-eng auto-tunnel p2p config unnumbered-interface Loopback0mpls traffic-eng auto-tunnel p2p tunnel-num min 1000 max 5000!mpls traffic-eng lsp attributes L3VPN-SRTE path-selection metric igp pce!ip community-list 1 permit 9999!route-map L3VPN-ODN-TE-INIT permit 10 match community 1 set attribute-set L3VPN-SRTE!route-map L3VPN-SR-ODN-Mark-Comm permit 10 match ip address L3VPN-ODN-Prefixes set community 9999 !!router bgp 100 address-family vpnv4 neighbor SvRR send-community both neighbor SvRR route-map L3VPN-ODN-TE-INIT in neighbor SvRR route-map L3VPN-SR-ODN-Mark-Comm out

SR-PCE configuration – IOS-XR

segment-routing traffic-eng pcc source-address ipv4 100.0.1.50 pce address ipv4 100.0.1.101 precedence 100 ! pce address ipv4 100.1.1.101 precedence 200 ! report-all timers delegation-timeout 10 timers deadtimer 60 timers initiated state 15 timers initiated orphan 10 ! !

SR-PCE configuration – IOS-XE

mpls traffic-eng tunnelsmpls traffic-eng pcc peer 100.0.1.101 source 100.0.1.51mpls traffic-eng pcc peer 100.0.1.111 source 100.0.1.51mpls traffic-eng pcc report-all

SR-TE Policy Configuration

At the foundation of CST is the use of Segment Routing Traffic Engineering Policies. SR-TE allow providers to create end to end traffic paths with engineered constraints to achieve a SLA objective. SR-TE Policies are either dynamically created by ODN (see ODN section) or users can configure SR-TE Policies on the head-end node.

SR-TE Color and Endpoint

The components uniquely identifying a SR-TE Policy to a destination PE node are its endpoint and color.

• The endpoint is the destination node loopback address. Note the endpoint address should not be an anycast address.
• The color is a 32-bit value which should have a SLA meaning to the network. The color allows for multiple SR-TE Policies to exist between a pair of nodes, each one with its own set of metrics and constraints.

SR-TE Candidate Paths

• Each SR-TE Policy configured on a node must have at least one candidate path defined.
• If multiple candidate paths are defined, only one is active at any one time.
• The candidate path with the higher preference value is preferred over candidate paths with a lower preference value.
• The candidate path configuration specifies whether the path is dynamic or uses an explicit segment list.
• Within the dynamic configuration one can specify whether to use a PCE or not, the metric type used in the path computation (IGP metric, latency, TE metric, hop count), and the additional constraints placed on the path (link affinities, flex-algo constraints, or a cumulative metric of type IGP metric, latency, TE Metric, or hop count)
• There is a default candidate path with a preference of 200 using head-end IGP path computation
• Each candidate path can have multiple explicit segment lists defined with a bandwidth weight value to load balance traffic across multiple explicit paths

Service to SR-TE Policy Forwarding - Per-Destination

Service traffic can be forwarded over SR-TE Policies in the CST design using per-destination automated steering. Per-destination steering utilizes two BGP components of the service route to forward traffic to a matching SR Policy

• A color extended community attached to the service route matching the SR Policy color
• The BGP next-hop address of the service route to match the endpoint of the SR Policy

Service to SR-TE Policy Forwarding - Per-Flow

Service traffic can also be forwarded over SR-TE Policies in the CST design using per-flow automated steering.
Per-flow automated steering uses the same BGP criteria as per-destination steering but also uses the CoS of the ingress packet to determine the proper SR Policy to steer traffic over.

SR-TE and ODN Configuration Examples

The following examples show SR-TE policies using persistent device configuration and the ODN policies to dynamic create the same SR Policies.

SR Policy using IGP metric, head-end computation

The local PE device will compute a path using the lowest cumulative IGP metric path to 100.0.1.50. Note in the multi-domain CST design, this computation will fail to nodes not found within the same IS-IS domain as the PE.

segment-routing traffic-eng policy GREEN-PE3-24 color 1024 end-point ipv4 100.0.1.50 candidate-paths preference 1 dynamic ! metric type igp

segment-routing traffic-eng on-demand color 1024 dynamic pcep ! anycast-sid-inclusion ! sid-algorithm 128 !

PCE delegated SR Policy using lowest IGP metric

This policy will request a path from the configured primary PCE with the lowest cumulative IGP metric to the endpoint 100.0.1.50

segment-routing traffic-eng policy GREEN-PE3-24 color 1024 end-point ipv4 100.0.1.50 candidate-paths preference 1 dynamic pcep ! metric type igp

PCE delegated SR Policy using lowest latency metric

This policy will request a path from the configured primary PCE with the lowest cumulative latency to the endpoint 100.0.1.50. As covered in the performance-measurement section, the per-link latency metric value used will be the dynamic/static PM value, a configured TE metric value, or the IGP metric.

segment-routing traffic-eng policy GREEN-PE3-24 color 1024 end-point ipv4 100.0.1.50 candidate-paths preference 1 dynamic pcep ! metric type latency 

segment-routing traffic-eng on-demand color 1024 dynamic pcep ! metric type latency !

PCE delegated SR Policy including Anycast SIDs

Anycast SIDs provide redundancy to hops in the SR-TE path. 1+N nodes share the same Loopback address and Node-SID. Traffic with the Anycast SID in the SID list will route to the closest node with the SID assigned based on IGP cost. The “anycast-sid-inclusion” command is required for the PCE or local computation to prefer Anycast SIDs when computing the end to end path.

policy Anycast-APE3-1 color 30001 end-point ipv4 101.0.1.50 candidate-paths preference 1 dynamic pcep ! metric type igp ! anycast-sid-inclusion

segment-routing traffic-eng on-demand color 30001 dynamic pcep ! anycast-sid-inclusion !

PCE delegated SR Policy using specific Flexible Algorithm

Please see the Flex-Algo section for more details on SR Flexible Algorithms. The following SR-TE policy will restrict path computation to links and nodes belonging to algo 128, using the lowest IGP metric to compute the path.

policy FA128-APE3-1 color 77801 end-point ipv4 101.0.1.50 candidate-paths preference 1 dynamic pcep ! metric type igp ! ! constraints segments sid-algorithm 128

on-demand color 77801 dynamic pcep ! metric type igp ! ! constraints segments sid-algorithm 128

SR Policy using explicit segment list

This policy does not perform any path computation, it will utilize the statically defined segment lists as the forwarding path across the network. The node does however check the validity of the node segments in the list. Each node SID in the segment list can be defined by either IP address or SID. The full path to the egress node must be defined in the list, but you do not need to define every node explicitly in the path. If you want the path to take a specific link the correct node and adjacency SID must be defined in the list. Multiple explicit paths can be defined with a weight assigned, the ratio of weights is used to balance traffic across each explicit path.

segment-routing traffic-eng segment-list anycast-path index 1 mpls label 17034 index 2 mpls label 16150 ! policy anycast-path-ape3 color 9999 end-point ipv4 100.0.1.50 candidate-paths preference 1 explicit segment-list anycast-path

Per-Flow Segment Routing Configuration (NCS Platforms)

The following configuration is required on the NCS 5500 / 5700 platforms to allocate the PFP Binding SID (BSID) from a specific label block.

mpls label blocks block name sample-pfp-bsid-block type pfp start 40000 end 41000 client any

Per-Flow QoS Configuration

The Forward Class must be set in the ingress QoS policy so traffic is steered into the correct child Per-Destination Policy.

policy-map per-flow-steering class MatchIPP1 set forward-class 1! class MatchIPP2 set forward-class 2! class MatchIPv4_SRC set forward-class 3 ! class MatchIPv6_SRC set forward-class 4 end-policy-map!class-map match-any MatchIPP1 match precedence 1end-class-map!class-map match-any MatchIPP2 match precedence 2end-class-map!class-map match-any MatchIPv4_SRC match access-group ipv4 ipv4_sourcesend-class-map!class-map match-any MatchIPv6_SRC match access-group ipv4 ipv6_sourcesend-class-mapipv4 access-list ipv4_sources 10 permit ipv4 100.0.0.0/24 any20 permit ipv4 100.0.1.0/24 any!ipv6 access-list ipv6_sources 10 permit ipv6 2001:100::/64 any 20 permit ipv6 2001:200::/64 any

Per-Flow Policy Configuration

This example shows both the child Per-Destination Policies as well as the parent Per-Flow Policy. Each Forward-Class is mapped to the color of the child policy. The default Forward Class is meant to catch traffic not matching a configured Forward Class.

segment-routing traffic-eng policy PERFLOW color 100 endpoint 1.1.1.4 candidate-paths preference 100 per-flow forward-class 0 color 10 forward-class 1 color 20 forward-class 2 color 30 forward-class 3 color 40 forward-class 4 color 50 forward-class default 0 ! policy pe1_fc0 color 10 end-point ipv4 192.168.11.1 candidate-paths preference 150 explicit segment-list PFL4-PE1-FC1 ! policy pe1_fc1 color 20 end-point ipv4 192.168.11.1 candidate-paths preference 150 dynamic ! policy pe1_fc2 color 30 end-point ipv4 192.168.11.1 candidate-paths preference 150 explicit segment-list PFL4-PE1-FC2 ! policy pe1_fc3 color 40 end-point ipv4 192.168.11.1 candidate-paths preference 150 dynamic 

On-Demand Next-Hop Per-Flow Configuration

The creation of the SR-TE Policies can be fully automated using ODN. ODN is used to create the child Per-Destination Policies as well as the Per-Flow Policy.

segment-routing traffic-eng on-demand color 10 dynamic metric type igp ! ! ! on-demand color 20 dynamic sid-algorithm 128 ! ! on-demand color 30 dynamic metric type te ! ! on-demand color 30 dynamic metric type igp ! ! on-demand color 50 dynamic metric type latency ! ! on-demand color 100 per-flow forward-class 0 color 10 forward-class 1 color 20 forward-class 2 color 30 forward-class 3 color 40 forward-class 4 color 50

QoS Implementation

Summary

Please see the CST 3.0 HLD for in-depth information on design choices.

Core QoS configuration

The core QoS policies defined for CST 3.0 utilize priority levels, with no bandwidth guarantees per traffic class. In a production network it is recommended to analyze traffic flows and determine an appropriate BW guarantee per traffic class. The core QoS uses four classes. Note the “video” class uses priority level 6 since only levels 6 and 7 are supported for high priority multicast.

Class maps used in QoS policies

Class maps are used within a policy map to match packet criteria or internal QoS markings like traffic-class or qos-group

class-map match-any match-ef-exp5 description High priority, EF match dscp 46 match mpls experimental topmost 5 end-class-map!class-map match-any match-cs5-exp4 description Second highest priority match dscp 40 match mpls experimental topmost 4 end-class-map!class-map match-any match-video-cs4-exp2 description Video match dscp 32 match mpls experimental topmost 2 end-class-map!class-map match-any match-cs6-exp6 description Highest priority control-plane traffic match dscp cs6 match mpls experimental topmost 6 end-class-map!class-map match-any match-qos-group-1 match qos-group 1 end-class-map!class-map match-any match-qos-group-2 match qos-group 2 end-class-map!class-map match-any match-qos-group-3 match qos-group 3 end-class-map!class-map match-any match-qos-group-6 match qos-group 3 end-class-map!class-map match-any match-traffic-class-1 description "Match highest priority traffic-class 1" match traffic-class 1 end-class-map!class-map match-any match-traffic-class-2 description "Match high priority traffic-class 2" match traffic-class 2 end-class-map!class-map match-any match-traffic-class-3 description "Match medium traffic-class 3" match traffic-class 3 end-class-map!class-map match-any match-traffic-class-6 description "Match video traffic-class 6" match traffic-class 6 end-class-map

Core ingress classifier policy

policy-map core-ingress-classifier class match-cs6-exp6 set traffic-class 1 ! class match-ef-exp5 set traffic-class 2 ! class match-cs5-exp4 set traffic-class 3 ! class match-video-cs4-exp2 set traffic-class 6 ! class class-default set mpls experimental topmost 0 set traffic-class 0 set dscp 0 ! end-policy-map!

Core egress queueing map

policy-map core-egress-queuing class match-traffic-class-2 priority level 2 queue-limit 100 us ! class match-traffic-class-3 priority level 3 queue-limit 500 us ! class match-traffic-class-6 priority level 6 queue-limit 500 us ! class match-traffic-class-1 priority level 1 queue-limit 500 us ! class class-default queue-limit 250 ms ! end-policy-map!

Core egress MPLS EXP marking map

The following policy must be applied for PE devices with MPLS-based VPN services in order for service traffic classified in a specific QoS Group to be marked. VLAN-based P2P L2VPN services will by default inspect the incoming 802.1p bits and copy those the egress MPLS EXP if no specific ingress policy overrides that behavior. Note the EXP can be set in either an ingress or egress QoS policy. This QoS example sets the EXP via the egress map.

policy-map core-egress-exp-marking class match-qos-group-1 set mpls experimental imposition 6 ! class match-qos-group-2 set mpls experimental imposition 5 ! class match-qos-group-3 set mpls experimental imposition 4 ! class match-qos-group-6 set mpls experimental imposition 2 ! class class-default set mpls experimental imposition 0 ! end-policy-map!

H-QoS configuration

Enabling H-QoS on NCS 540 and NCS 5500

Enabling H-QoS on the NCS platforms requires the following global command and requires a reload of the device.

hw-module profile qos hqos-enable

Example H-QoS policy for 5G services

The following H-QoS policy represents an example QoS policy reserving 5Gbps on a sub-interface. On ingress each child class is policed to a certain percentage of the 5Gbps policer. In the egress queuing policy, shaping is used with guaranteed each class a certain amount of egress bandwidth, with high priority traffic being serviced in a low-latency queue (LLQ).

Class maps used in ingress H-QoS policies

class-map match-any edge-hqos-2-in match dscp 46 end-class-map!class-map match-any edge-hqos-3-in match dscp 40 end-class-map!class-map match-any edge-hqos-6-in match dscp 32 end-class-map

Parent ingress QoS policy

policy-map hqos-ingress-parent-5g class class-default service-policy hqos-ingress-child-policer police rate 5 gbps ! ! end-policy-map

H-QoS ingress child policies

policy-map hqos-ingress-child-policer class edge-hqos-2-in set traffic-class 2 police rate percent 10 ! ! class edge-hqos-3-in set traffic-class 3 police rate percent 30 ! ! class edge-hqos-6-in set traffic-class 6 police rate percent 30 ! ! class class-default set traffic-class 0 set dscp 0 police rate percent 100 ! ! end-policy-map

Egress H-QoS parent policy (Priority levels)

policy-map hqos-egress-parent-4g-priority class class-default service-policy hqos-egress-child-priority shape average 4 gbps ! end-policy-map!

Egress H-QoS child using priority only

In this policy all classes can access 100% of the bandwidth, queues are services based on priority level. The lower priority level has preference.

policy-map hqos-egress-child-priority class match-traffic-class-2 shape average percent 100 priority level 2 ! class match-traffic-class-3 shape average percent 100 priority level 3 ! class match-traffic-class-6 priority level 4 shape average percent 100 ! class class-default ! end-policy-map

Egress H-QoS child using reserved bandwidth

In this policy each class is reserved a certain percentage of bandwidth. Each class may utilize up to 100% of the bandwidth, if traffic exceeds the guaranteed bandwidth it is eligible for drop.

policy-map hqos-egress-child-bw class match-traffic-class-2 bandwidth remaining percent 30 ! class match-traffic-class-3 bandwidth remaining percent 30 ! class match-traffic-class-6 bandwidth remaining percent 30 ! class class-default bandwidth remaining percent 10 ! end-policy-map

Egress H-QoS child using shaping

In this policy each class is shaped to a defined amount and cannot exceed the defined bandwidth.

policy-map hqos-egress-child-shaping class match-traffic-class-2 shape average percent 30 ! class match-traffic-class-3 shape average percent 30 ! class match-traffic-class-6 shape average percent 30 ! class class-default shape average percent 10 ! end-policy-map!

Support for Time Sensitive Networking in N540-FH-CSR-SYS and N540-FH-AGG-SYS

The Fronthaul family of NCS 540 routers support frame preemption based on the IEEE 802.1Qbu-2016 and Time Sensitive Networking (TSN) standards.

Time Sensitive Networking (TSN) is a set of IEEE standards that addresses the timing-critical aspect of signal flow in a packet switched Ethernet network to ensure deterministic operation. TSN operates at the Ethernet layer on physical interfaces. Frames are marked with a specific QoS class (typically 7 in a device with classes 0-7) qualify as express traffic, while other classes other than control plane traffic are marked as preemptable traffic.

This allows critical signaling traffic to traverse a device as quickly as possible without having to wait for lower priority frames before being transmitted on the wire.

Please see the TSN configuration guide for NCS 540 Fronthaul routers at https://www.cisco.com/c/en/us/td/docs/iosxr/ncs5xx/fronthaul/b-fronthaul-config-guide-ncs540-fh/m-fh-tsn-ncs540.pdf

Time Sensitive Networking Configuration

class-map match-any express-traffic match cos 7class-map match-any preemptable-traffic match cos 2class-map match-any express-class match traffic-class 7 class-map match-any preemptable-class match traffic-class 2 

policy-map mark-traffic class express-traffic set traffic-class 7 class preemptable-traffic set traffic-class 2

policy-map tsn-policy class express-class priority level 1 class preemptable-class priority level 2 class best-effort bandwidth percent 50

Ingress Interface

interface TenGigabitEthernet0/0/0/1 ip address 14.0.0.1 255.255.255.0 service-policy input mark-traffic 

Egress Interface

interface TenGigabitEthernet0/0/0/0 ip address 12.0.0.1 255.255.255.0 service-policy output tsn-policy frame-preemption

End-To-End VPN Services

Figure 6: End-To-End Services Table

End-To-End VPN Services Data Plane

Figure 10: End-To-End Services Data Plane

L3VPN MP-BGP VPNv4 On-Demand Next-Hop

Figure 7: L3VPN MP-BGP VPNv4 On-Demand Next-Hop Control Plane

Access Routers: Cisco ASR920 IOS-XE and NCS540 IOS-XR

1. Operator: New VPNv4 instance via CLI or NSO

2. Access Router: Advertises/receives VPNv4 routes to/from Services Route-Reflector (sRR)

3. Access Router: Request SR-PCE to provide path (shortest IGP metric) to remote access router

4. SR-PCE: Computes and provides the path to remote router(s)

5. Access Router: Programs Segment Routing Traffic Engineering (SRTE) Policy to reach remote access router

Please refer to “On Demand Next-Hop (ODN)” sections for initial ODN configuration.

Access Router Service Provisioning (IOS-XR)

ODN route-policy configuration

extcommunity-set opaque ODN-GREEN 100end-setroute-policy ODN-L3VPN-OUT set extcommunity color ODN-GREEN passend-policy

VRF definition configuration

vrf ODN-L3VPN rd 100:1 address-family ipv4 unicast import route-target 100:1 ! export route-target export route-policy ODN-L3VPN-OUT 100:1 ! ! address-family ipv6 unicast import route-target 100:1 ! export route-target export route-policy ODN-L3VPN-OUT 100:1 ! !

VRF Interface configuration

interface TenGigE0/0/0/23.2000 mtu 9216 vrf ODN-L3VPN ipv4 address 172.106.1.1 255.255.255.0 encapsulation dot1q 2000

BGP VRF configuration with static/connected only

router bgp 100 vrf VRF-MLDP rd auto address-family ipv4 unicast redistribute connected redistribute static ! address-family ipv6 unicast redistribute connected redistribute static !

Access Router Service Provisioning (IOS-XE)

VRF definition configuration

vrf definition L3VPN-SRODN-1 rd 100:100 route-target export 100:100 route-target import 100:100 address-family ipv4 exit-address-family

VRF Interface configuration

interface GigabitEthernet0/0/2 mtu 9216 vrf forwarding L3VPN-SRODN-1 ip address 10.5.1.1 255.255.255.0 negotiation autoend

BGP VRF configuration Static & BGP neighbor

Static routing configuration

router bgp 100 address-family ipv4 vrf L3VPN-SRODN-1 redistribute connected exit-address-family

BGP neighborconfiguration

router bgp 100 neighbor Customer-1 peer-group neighbor Customer-1 remote-as 200 neighbor 10.10.10.1 peer-group Customer-1 address-family ipv4 vrf L3VPN-SRODN-2 neighbor 10.10.10.1 activate exit-address-family

L2VPN Single-Homed EVPN-VPWS On-Demand Next-Hop

Figure 8: L2VPN Single-Homed EVPN-VPWS On-Demand Next-Hop Control Plane

Access Routers: Cisco NCS5501-SE IOS-XR

1. Operator: New EVPN-VPWS instance via CLI or NSO

2. Access Router: Advertises/receives EVPN-VPWS instance to/from Services Route-Reflector (sRR)

3. Access Router: Request SR-PCE to provide path (shortest IGP metric) to remote access router

4. SR-PCE: Computes and provides the path to remote router(s)

5. Access Router: Programs Segment Routing Traffic Engineering (SRTE) Policy to reach remote access router

Note: Please refer to On Demand Next-Hop (ODN) – IOS-XR section for initial ODN configuration. The correct EVPN L2VPN routes must be advertised with a specific color ext-community to trigger dynamic SR Policy instantiation.

Access Router Service Provisioning (IOS-XR):

Port based service configuration

l2vpn xconnect group evpn_vpws p2p odn-1 interface TenGigE0/0/0/5 neighbor evpn evi 1000 target 1 source 1 interface TenGigE0/0/0/5 l2transport

VLAN Based service configuration

l2vpn xconnect group evpn_vpws p2p odn-1 neighbor evpn evi 1000 target 1 source 1 !! interface TenGigE0/0/0/5.1 l2transport encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric!

L2VPN Static Pseudowire (PW) – Preferred Path (PCEP)

Figure 9: L2VPN Static Pseudowire (PW) – Preferred Path (PCEP) Control Plane

Access Routers: Cisco NCS5501-SE IOS-XR or Cisco ASR920 IOS-XE

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Access Router: Request SR-PCE to provide path (shortest IGP metric) to remote access router

3. SR-PCE: Computes and provides the path to remote router(s)

4. Access Router: Programs Segment Routing Traffic Engineering (SRTE) Policy to reach remote access router

Access Router Service Provisioning (IOS-XR):

Note: EVPN VPWS dual homing is not supported when using an SR-TE preferred path.

Note: In IOS-XR 6.6.3 the SR Policy used as the preferred path must be referenced by its generated name and not the configured policy name. This requires first issuing the command

Define SR Policy

 traffic-eng policy GREEN-PE3-1 color 1001 end-point ipv4 100.0.1.50 candidate-paths preference 1 dynamic pcep ! metric type igp

Determine auto-configured policy name The auto-configured policy name will be persistant and must be used as a reference in the L2VPN preferred-path configuration.

RP/0/RP0/CPU0:A-PE8#show segment-routing traffic-eng policy candidate-path name GREEN-PE3-1 SR-TE policy database Color: 1001, End-point: 100.0.1.50 Name: srte_c_1001_ep_100.0.1.50 

Port Based Service configuration

interface TenGigE0/0/0/15 l2transport ! ! l2vpn pw-class static-pw-class-PE3 encapsulation mpls control-word preferred-path sr-te policy srte_c_1001_ep_100.0.1.50 ! ! ! p2p Static-PW-to-PE3-1 interface TenGigE0/0/0/15 neighbor ipv4 100.0.0.3 pw-id 1000 mpls static label local 1000 remote 1000 pw-class static-pw-class-PE3 

VLAN Based Service configuration

interface TenGigE0/0/0/5.1001 l2transport encapsulation dot1q 1001 rewrite ingress tag pop 1 symmetric ! ! l2vpn pw-class static-pw-class-PE3 encapsulation mpls control-word preferred-path sr-te policy srte_c_1001_ep_100.0.1.50 p2p Static-PW-to-PE7-2 interface TenGigE0/0/0/5.1001 neighbor ipv4 100.0.0.3 pw-id 1001 mpls static label local 1001 remote 1001 pw-class static-pw-class-PE3 

Access Router Service Provisioning (IOS-XE):

Port Based service with Static OAM configuration

interface GigabitEthernet0/0/1 mtu 9216 no ip address negotiation auto no keepalive service instance 10 ethernet encapsulation default xconnect 100.0.2.54 100 encapsulation mpls manual pw-class mpls mpls label 100 100 no mpls control-word ! pseudowire-static-oam class static-oam timeout refresh send 10 ttl 255 ! ! ! pseudowire-class mpls encapsulation mpls no control-word protocol none preferred-path interface Tunnel1 status protocol notification static static-oam ! 

VLAN Based Service configuration

interface GigabitEthernet0/0/1 no ip address negotiation auto service instance 1 ethernet Static-VPWS-EVC encapsulation dot1q 10 rewrite ingress tag pop 1 symmetric xconnect 100.0.2.54 100 encapsulation mpls manual pw-class mpls mpls label 100 100 no mpls control-word ! ! ! pseudowire-class mpls encapsulation mpls no control-word protocol none preferred-path interface Tunnel1 

L2VPN EVPN E-Tree

Note: ODN support for EVPN E-Tree is supported on ASR9K only in CST 3.5. Support for E-Tree across all CST IOS-XR nodes will be covered in CST 4.0 based on IOS-XR 7.2.2. In CST 3.5, if using E-Tree across multiple IGP domains, SR-TE Policies must be configured between all Root nodes and between all Root and Leaf nodes.

IOS-XR Root Node Configuraiton

evpn evi 100 advertise-mac ! ! l2vpn bridge group etree bridge-domain etree-ftth interface TenGigE0/0/0/14.100 routed interface BVI100 ! evi 100 

IOS-XR Leaf Node Configuration

A single command is needed to enable leaf function for an EVI. Configuring “etree leaf” will signal to other nodes this is a leaf node. In this case we also have a L3 IRB configured within the EVI. In order to isolate the two ACs, each AC is configured with the “split-horizon group” configuration command. The BVI interface is configured with “local-proxy-arp” to intercept ARP requests between hosts on each AC. This is needed if hosts in two different ACs are using the same IP address subnet, since ARP traffic will be suppressed acrossed the ACs.

evpn evi 100 etree leaf ! advertise-mac ! ! l2vpn bridge group etree bridge-domain etree-ftth interface TenGigE0/0/0/23.1098 split-horizon-group interface TenGigE0/0/0/24.1098 split-horizon group routed interface BVI100 ! evi 100 

interface BVI11011 local-proxy-arp

Hierarchical Services

Figure 11: Hierarchical Services Table

L3VPN – Single-Homed EVPN-VPWS, MP-BGP VPNv4/6 with Pseudowire-Headend (PWHE)

Figure 12: L3VPN – Single-Homed EVPN-VPWS, MP-BGP VPNv4/6 with Pseudowire-Headend (PWHE) Control Plane

Access Routers: Cisco NCS5501-SE IOS-XR or Cisco ASR920 IOS-XE

1. Operator: New EVPN-VPWS instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR

1. Operator: New EVPN-VPWS instance via CLI or NSO

2. Provider Edge Router: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L3VPN instance (VPNv4/6) together with Pseudowire-Headend (PWHE) via CLI or NSO

4. Provider Edge Router: Path to remote PE is known via CORE-ISIS IGP.

Access Router Service Provisioning (IOS-XR):

VLAN based service configuration

l2vpn xconnect group evpn-vpws-l3vpn-PE1 p2p L3VPN-VRF1 interface TenGigE0/0/0/5.501 neighbor evpn evi 13 target 501 source 501 ! ! !interface TenGigE0/0/0/5.501 l2transport encapsulation dot1q 501 rewrite ingress tag pop 1 symmetric

Port based service configuration

l2vpn xconnect group evpn-vpws-l3vpn-PE1 p2p odn-1 interface TenGigE0/0/0/5 neighbor evpn evi 13 target 502 source 502 ! ! !! interface TenGigE0/0/0/5 l2transport

Access Router Service Provisioning (IOS-XE):

VLAN based service configuration

l2vpn evpn instance 14 point-to-point vpws context evpn-pe4-pe1 service target 501 source 501 member GigabitEthernet0/0/1 service-instance 501 !interface GigabitEthernet0/0/1 service instance 501 ethernet encapsulation dot1q 501 rewrite ingress tag pop 1 symmetric ! 

Port based service configuration

l2vpn evpn instance 14 point-to-point vpws context evpn-pe4-pe1 service target 501 source 501 member GigabitEthernet0/0/1 service-instance 501 !interface GigabitEthernet0/0/1 service instance 501 ethernet encapsulation default

Provider Edge Router Service Provisioning (IOS-XR):

VRF configuration

vrf L3VPN-ODNTE-VRF1 address-family ipv4 unicast import route-target 100:501 ! export route-target 100:501 ! ! address-family ipv6 unicast import route-target 100:501 ! export route-target 100:501 ! !

BGP configuration

router bgp 100 vrf L3VPN-ODNTE-VRF1 rd 100:501 address-family ipv4 unicast redistribute connected ! address-family ipv6 unicast redistribute connected ! !

PWHE configuration

interface PW-Ether1 vrf L3VPN-ODNTE-VRF1 ipv4 address 10.13.1.1 255.255.255.0 ipv6 address 1000:10:13::1/126 attach generic-interface-list PWHE!

EVPN VPWS configuration towards Access PE

l2vpn xconnect group evpn-vpws-l3vpn-A-PE3 p2p L3VPN-ODNTE-VRF1 interface PW-Ether1 neighbor evpn evi 13 target 501 source 501 !

Figure 13: L3VPN – Single-Homed EVPN-VPWS, MP-BGP VPNv4/6 with Pseudowire-Headend (PWHE) Data Plane

L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4 with Anycast IRB

Figure 14: L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4 with Anycast IRB Control Plane

Access Routers: Cisco NCS5501-SE IOS-XR or Cisco ASR920 IOS-XE

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR (Same on both PE routers in same location PE1/2 and PE3/4)

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Provider Edge Routers: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L3VPN instance (VPNv4/6) together with Anycast IRB via CLI or NSO

4. Provider Edge Routers: Path to remote PEs is known via CORE-ISIS IGP.

Access Router Service Provisioning (IOS-XR):

VLAN based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2.1 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !interface TenGigE0/0/0/2.1 l2transport encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric !! l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word !

Port based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !interface TenGigE0/0/0/2 l2transport !! l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word !

Access Router Service Provisioning (IOS-XE):

VLAN based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Port based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation default xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Provider Edge Routers Service Provisioning (IOS-XR):

cef adjacency route override rib

AnyCast Loopback configuration

interface Loopback100 description Anycast ipv4 address 100.100.100.12 255.255.255.255!router isis ACCESS interface Loopback100 address-family ipv4 unicast prefix-sid index 1012 n-flag-clear 

L2VPN configuration

l2vpn bridge group Static-VPWS-H-L3VPN-IRB bridge-domain VRF1 neighbor 100.0.1.50 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! neighbor 100.0.1.51 pw-id 4001 mpls static label local 4001 remote 4001 pw-class static-pw-h-l3vpn-class ! routed interface BVI1 split-horizon group core ! evi 12001 ! !

EVPN configuration

evpn evi 12001 ! advertise-mac ! virtual neighbor 100.0.1.50 pw-id 5001 ethernet-segment identifier type 0 12.00.00.00.00.00.50.00.01

Anycast IRB configuration

interface BVI1 host-routing vrf L3VPN-AnyCast-ODNTE-VRF1 ipv4 address 12.0.1.1 255.255.255.0 mac-address 12.0.1 load-interval 30

VRF configuration

vrf L3VPN-AnyCast-ODNTE-VRF1 address-family ipv4 unicast import route-target 100:10001 ! export route-target 100:10001 ! !!

BGP configuration

router bgp 100 vrf L3VPN-AnyCast-ODNTE-VRF1 rd auto address-family ipv4 unicast redistribute connected ! !

Figure 15: L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4/6 with Anycast IRB Datal Plane

L2/L3VPN – Anycast Static Pseudowire (PW), Multipoint EVPN with Anycast IRB

Figure 16: L2/L3VPN – Anycast Static Pseudowire (PW), Multipoint EVPN with Anycast IRB Control Plane

Access Routers: Cisco NCS5501-SE IOS-XR or Cisco ASR920 IOS-XE

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR (Same on both PE routers in same location PE1/2 and PE3/4)

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Provider Edge Routers: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L2VPN Multipoint EVPN instance together with Anycast IRB via CLI or NSO (Anycast IRB is optional when L2 and L3 is required in same service instance)

4. Provider Edge Routers: Path to remote PEs is known via CORE-ISIS IGP.

Please note that provisioning on Access and Provider Edge routers is same as in “L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4/6 with Anycast IRB”. In this use case there is BGP EVPN instead of MP-BGP VPNv4/6 in the core.

Access Router Service Provisioning (IOS-XR):

VLAN based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2.1 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !interface TenGigE0/0/0/2.1 l2transport encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric!l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word !

Port based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !!interface TenGigE0/0/0/2 l2transport!l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word

Access Router Service Provisioning (IOS-XE):

VLAN based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Port based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation default xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Provider Edge Routers Service Provisioning (IOS-XR):

cef adjacency route override rib

AnyCast Loopback configuration

interface Loopback100 description Anycast ipv4 address 100.100.100.12 255.255.255.255!router isis ACCESS interface Loopback100 address-family ipv4 unicast prefix-sid index 1012

L2VPN Configuration

l2vpn bridge group Static-VPWS-H-L3VPN-IRB bridge-domain VRF1 neighbor 100.0.1.50 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! neighbor 100.0.1.51 pw-id 4001 mpls static label local 4001 remote 4001 pw-class static-pw-h-l3vpn-class ! routed interface BVI1 split-horizon group core ! evi 12001 ! !

EVPN configuration

evpn evi 12001 ! advertise-mac ! ! virtual neighbor 100.0.1.50 pw-id 5001 ethernet-segment identifier type 0 12.00.00.00.00.00.50.00.01

Anycast IRB configuration

interface BVI1 host-routing vrf L3VPN-AnyCast-ODNTE-VRF1 ipv4 address 12.0.1.1 255.255.255.0 mac-address 12.0.1 load-interval 30!

VRF configuration

vrf L3VPN-AnyCast-ODNTE-VRF1 address-family ipv4 unicast import route-target 100:10001 ! export route-target 100:10001 ! !!

BGP configuration

router bgp 100 vrf L3VPN-AnyCast-ODNTE-VRF1 rd auto address-family ipv4 unicast redistribute connected ! ! 

Figure 17: L2/L3VPN – Anycast Static Pseudowire (PW), Multipoint EVPN with Anycast IRB Data Plane

L2/L3VPN – EVPN Head-End Configuration

Figure 16: L2/L3VPN – EVPN Head-End

Access Routers: Cisco NCS 540, 5500, 560 IOS-XR

1. Operator: New EVPN-VPWS Pseudowire (PW) instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR (Same on both PE routers in same location PE1/2 and PE3/4)

1. Operator: New EVPN-VPWS Pseudowire (PW) instance via CLI or NSO

2. Provider Edge Routers: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L2VPN Multipoint EVPN instance together with L3 PWHE interface via CLI or NSO

4. Provider Edge Routers: Path to remote PEs is known via CORE-ISIS IGP.

Access Router Service Provisioning (IOS-XR):

Interface Configuration

interface TenGigE0/0/0/5.2002 l2transport description EVPN-VPWS-PWHE-HEADEND encapsulation dot1q 2002!interface TenGigE0/0/0/5.2003 l2transport description EVPN-VPWS-PWHE-HEADEND encapsulation dot1q 2003!interface TenGigE0/0/0/5.2022 l2transport description EVPN-VPWS-PWHE-HEADEND encapsulation dot1q 2022

L2VPN Configuration In this example we use the NCS 540/5500 flexible xconnect service type to bundle multiple downstream interfaces into a single EVPN-VPWS to the EVPN Head End as a trunk. FXC can bundle VLANs from the same physical interface or different physical interfaces.

l2vpn flexible-xconnect-service vlan-unaware PWHE-Headend interface TenGigE0/0/0/5.2002 interface TenGigE0/0/0/5.2003 interface TenGigE0/0/0/5.2022 neighbor evpn evi 2002 target 2002

Provider Edge Routers Service Provisioning (IOS-XR):

A similar configuration is found on all PE routers. Each pair of EVPN-HE routers share the same IP addresses and EVPN ESI on their PW-Ether2002 interfaces.

cef adjacency route override rib

EVPN-HE L3 Interface Configuration The following shows an example of both untagged and taggged interfaces. The same EVPN-VPWS is used as a trunk to carry traffic between Access and Head-End PE.

interface PW-Ether2002 mtu 1518 ipv4 address 100.9.2.1 255.255.255.252 vrf L3VPN-AnyCast-ODNTE-VRF1 mac-address 0.1111.1 load-interval 30 attach generic-interface-list PWHE!interface PW-Ether2002.2002 vrf L3VPN-ODNTE-VRF1 ipv4 address 11.4.1.1 255.255.255.0 encapsulation dot1q 2002!interface PW-Ether2002.2003 ipv4 address 11.5.1.1 255.255.255.0 encapsulation dot1q 2003

EVPN Configuration

evpn interface PW-Ether2002 ethernet-segment identifier type 0 99.99.99.99.99.01.00.00.00 convergence nexthop-tracking

EVPN-VPWS to Access PE

xconnect group EVPN-HeadEnd p2p L3VPN-ODNTE-VRF11 interface PW-Ether2002 neighbor evpn evi 2002 target 2002 source 2002

VRF configuration

vrf L3VPN-AnyCast-ODNTE-VRF1 address-family ipv4 unicast import route-target 100:10001 ! export route-target 100:10001 !

L2/L3VPN – EVPN Centralized Gateway

Figure 16: L2/L3VPN – EVPN Centralized Gateway

Access Routers: Cisco NCS 540, 5500, 560 IOS-XR

1. Operator: New EVPN-ELAN or ETREE instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR (Same on both PE routers in same location PE1/2 and PE3/4)

1. Operator: New EVPN-ELAN or ETREE instance via CLI or NSO

2. Provider Edge Routers: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L3VPN Multipoint EVPN instance together with Anycast IRB interface via CLI or NSO

4. Provider Edge Routers: Path to remote PEs is known via CORE-ISIS IGP.

Access Router Service Provisioning (IOS-XR):

Interface Configuration

interface TenGigE0/0/0/5.2300 l2transport description EVPN-ELAN-CGW1-PE1/PE2 encapsulation dot1q 2300 rewrite ingress tag pop 1 symmetric

L2VPN and EVPN Configuration

l2vpn bridge group EVPN-ELAN-CGW1 bridge-domain ELAN-CGW1 interface TenGigE0/0/0/5.2300 ! evi 2400 ! !evpn evi 2400 advertise-mac

Provider Edge Routers Service Provisioning (IOS-XR):

A similar configuration is found on all PE routers. Each pair of EVPN-HE routers share the same IP addresses and MAC address providing a redundant Anycast IRB L3 gateway to L2 connected access devices.

EVPN CGW L3 BVI Interface Configuration In this example the interface is part of a core L3VPN, but the interface could reside in the global routing table (default VRF).

interface BVI100 vrf cgw ipv4 address 100.10.1.1 255.255.0.0 ipv6 address 100:10::1/64 mac-address 0.dc1.dc2

L2VPN Configuration Note the access-evi configuration used for the EVI connected to the A-PE access routers.

l2vpn bridge group EVPN-ELAN-CGW1 bridge-domain ELAN-CGW1 access-evi 2400 routed interface BVI100

EVPN Configuration In this case we are using ODN to create on-demand SR-TE policies between the core CGW PEs and access PEs.

evpn evi 2400 bgp route-policy export cgw_srte_odn route-policy import cgw_srte_odn ! advertise-mac bvi-mac ! virtual access-evi ethernet-segment identifier type 0 00.00.ac.ce.55.00.e1.00.00 ! core-isolation-group 1 !!

VRF configuration

vrf cgw address-family ipv4 unicast import route-target 10:10 ! export route-policy C1234 export route-target 10:10 ! ! address-family ipv6 unicast export route-policy C1234

Ethernet CFM for L2VPN service assurance

Ethernet Connectivity Fault Management is an Ethernet OAM component used to validate end-to-end connectivity between service endpoints. Ethernet CFM is defined by two standards, 802.1ag and Y.1731. Within an SP network, Maintenance Domains are created based on service scope. Domains are typically separated by operator boundaries and may be nested but cannot overlap. Within each service, maintenance points can be created to verify bi-directional end to end connectivity. These are known as MEPs (Maintenance End-Point) and MIPs (Maintenance Intermediate Points). These maintenance points process CFM messages. A MEP is configured at service endpoints and has directionality where an “up” MEP faces the core of the network and a “down” MEP faces a CE device or NNI port. MIPs are optional and are created dynamically. Detailed information on Ethernet CFM configuration and operation can be found at https://www.cisco.com/c/en/us/td/docs/iosxr/ncs5500/interfaces/75x/configuration/guide/b-interfaces-hardware-component-cg-ncs5500-75x/m-configuring-ethernet-oam.html

Maintenance Domain configuration

A Maintenance Domain is defined by a unique name and associated level. The level can be 0-7. The numerical identifier usually corresponds to the scope of the MD, where 7 is associated with CE endpoints, 6 associated with PE devices connected to a CE. Additional levels may be required based on the topology and service boundaries which occur along the end-to-end service. In this example we only a single domain and utilize level 0 for all MEPs.

ethernet cfm domain EVPN-VPWS-PE3-PE8 level 0

MEP configuration for EVPN-VPWS services

For L2VPN xconnect services, each service must have a MEP created on the end PE device. There are two components to defining a MEP, first defining the Ethernet CFM “service” and then defining the MEP on the physical or logical interface participating in the L2VPN xconnect service. In the following configuration the xconnect group “EVPN-VPWS-ODN-PE3” and P2P EVPN VPWS service odn-8 are already defined. The Ethernet CFM service of “odn-8” does NOT have to match the xconnect service name. The MEP crosscheck defines a remote MEP to listen for Continuity Check messages from. It does not have to be the same as the local MEP defined on the physical sub-interface (103), but for P2P services it is best practice to make them identical. This configuration will send Ethernet CFM Continuity Check (CC) messages every 1 minute to verify end to end reachability.

L2VPN configuration

l2vpn xconnect group EVPN-VPWS-ODN-PE3 p2p odn-8 interface TenGigE0/0/0/23.8 neighbor evpn evi 1318 target 8 source 8 ! ! !!

Physical sub-interface configuration

interface TenGigE0/0/0/23.8 l2transport encapsulation dot1q 8 rewrite ingress tag pop 1 symmetric ethernet cfm mep domain EVPN-VPWS-PE3-PE8 service odn-8 mep-id 103 ! !!

Ethernet CFM service configuration

ethernet cfm domain EVPN-VPWS-PE3-PE8 service odn-8 xconnect group EVPN-VPWS-ODN-PE3 p2p odn-8 mip auto-create all continuity-check interval 1m mep crosscheck mep-id 103 ! log crosscheck errors log continuity-check errors log continuity-check mep changes ! !!

Multicast Source Distribution using BGP Multicast AFI/SAFI

The Converged SDN Transport is inherently multi-domain to increase scalability. Multicast distribution trees built across the network using either native PIM, mLDP, or SR Tree-SID require the source be known to the receiver nodes to satisfy multicast’s RPF (Reverse Path Forwarding) check. The recommended way to distribute source addresses across the network is use the BGP IPv4/IPv6 multicast address family, utilizing the ABR nodes as inline RRs.

In the case of MVPN the sources are distributed inside the L3VPN as VPNV4 and VPNV6 prefixes.

Multicast BGP Configuration

router bgp 100 ! address-family ipv4 multicast redistribute connected route-policy mcast-sources ! address-family ipv6 multicast redistribute connected route-policy mcast-sources 

Multicast Profile 14 using mLDP and ODN L3VPN

In ths service example we will implement multicast delivery across the CST network using mLDP transport for multicast and SR-MPLS for unicast traffic. L3VPN SR paths will be dynamically created using ODN. Multicast profile 14 is the “Partitioned MDT - MLDP P2MP - BGP-AD - BGP C-Mcast Signaling” Using this profile each mVPN will use a dedicated P2MP tree, endpoints will be auto-discovered using NG-MVPN BGP NLRI, and customer multicast state such as source streams, PIM, and IGMP membership data will be signaled using BGP. Profile 14 is the recommended profile for high scale and utilizing label-switched multicast (LSM) across the core.

Please note that mLDP requires an IGP path to the source PE loopback address. The CST design utilizes a multi-domain approach which normally does not advertise IGP routes across domain boundaries. If mLDP is being utilized across domains, controlled redistribution should be used to advertise the source PE loopback addresses to receiver PEs

Multicast core configuration

The multicast “core” includes transit endpoints participating in mLDP only. See the mLDP core configuration section for details on end-to-end mLDP configuration.

Unicast L3VPN PE configuration

In order to complete an RPF check for SSM sources, unicast L3VPN configuration is required. Additionally the VRF must be defined under the BGP configuration with the NG-MVPN address families configured. In our use case we are utilizing ODN for creating the paths between L3VPN endpoints with a route-policy attached to the mVPN VRF to set a specific color on advertised routes.

ODN opaque ext-community set

extcommunity-set opaque MLDP 1000end-set

ODN route-policy

route-policy ODN-MVPN set extcommunity color MLDP passend-policy

Global L3VPN VRF definition

vrf VRF-MLDP address-family ipv4 unicast import route-target 100:38 ! export route-policy ODN-MVPN export route-target 100:38 ! ! address-family ipv6 unicast import route-target 100:38 ! export route-policy ODN-MVPN export route-target 100:38 ! !!

BGP configuration

router bgp 100 vrf VRF-MLDP rd auto address-family ipv4 unicast redistribute connected redistribute static ! address-family ipv6 unicast redistribute connected redistribute static ! address-family ipv4 mvpn ! address-family ipv6 mvpn ! !!

Multicast PE configuration

The multicast “edge” includes all endpoints connected to native multicast sources or receivers.

Define RPF policy

route-policy mldp-partitioned-p2mp set core-tree mldp-partitioned-p2mpend-policy!

Enable Multicast and define mVPN VRF

multicast-routing address-family ipv4 interface Loopback0 enable ! ! vrf VRF-MLDP address-family ipv4 mdt source Loopback0 rate-per-route interface all enable accounting per-prefix bgp auto-discovery mldp ! mdt partitioned mldp ipv4 p2mp mdt data 100 ! !!

Enable PIM for mVPN VRF In this instance there is an interface TenGigE0/0/0/23.2000 which is using PIM within the VRF

router pim address-family ipv4 rp-address 100.0.1.50 ! vrf VRF-MLDP address-family ipv4 rpf topology route-policy mldp-partitioned-p2mp mdt c-multicast-routing bgp ! interface TenGigE0/0/0/23.2000 enable ! !

Enable IGMP for mVPN VRF interface To discover listeners for a specific group, enable IGMP on interfaces within the VRF. These interested receivers will be advertised via BGP to establish end to end P2MP trees from the source.

router igmp vrf VRF-MLDP interface TenGigE0/0/0/23.2001 ! version 3 !!

Multicast distribution using Tree-SID with static S,G Mapping

Tree-SID utilizes only Segment Routing to create and forward multicast traffic across an optimized tree. The Tree-SID tree is configured on the SR-PCE for deployment to the network. PCEP is used to instantiate the correct computed segments end to end. On the head-end source node,

Note: Tree-SID requires all nodes in the multicast distribution network to have connections to the same SR-PCE instances, please see the PCEP configuration section of the Implmentation Guide

Tree-SID SR-PCE Configuration

Endpoint Set Configuration

The P2MP endpoint sets are defined outside of the SR Tree-SID Policy configuration in order to be reusaable across multiple trees. This is a required step in the configuration of Tree-SID.

pce address ipv4 100.0.1.101 timers reoptimization 600 ! segment-routing traffic-eng p2mp endpoint-set APE7-APE8 ipv4 100.0.2.57 ipv4 100.0.2.58 ! timers reoptimization 120 timers cleanup 30

P2MP Tree-SID SR Policy Configuration

This configuration defines the Tree-SID P2MP SR Policy to be used across the network. Note the name of the Tree-SID must be unique across the netowrk and referenced explicitly on all source and receiver nodes. Within the policy configuration, supported constraints can be applied during path computation of the optimized P2MP tree. Note the source address must be specified and the MPLS label used must be within the SRLB for all nodes across the network.

pce segment-routing traffic-eng policy treesid-1 source ipv4 100.0.0.1 color 100 endpoint-set APE7-APE8 treesid mpls 18600 candidate-paths constraints affinity include-any color1 ! ! ! preference 100 dynamic metric type igp ! ! !

Tree-SID Common Config on All Nodes

Segment Routing Local Block

While the SRLB config is covered elsewhere in this guide, it is recommended to set the values the same across the Tree-SID domain. The values shown are for demonstration only.

segment-routing local-block 18000 19000 !!

PCEP Configuration

Tree-SID relies on PCE initiated segments to the node, so a session to the PCE is required for all nodes in the domain.

segment-routing traffic-eng pcc source-address ipv4 100.0.2.53 pce address ipv4 100.0.1.101 precedence 200 ! pce address ipv4 100.0.2.101 precedence 100 ! pce address ipv4 100.0.2.102 precedence 100 ! report-all timers delegation-timeout 10 timers deadtimer 60 timers initiated state 15 timers initiated orphan 10 ! !!

Static Tree-SID Source Node Multicast Configuration

PIM Configuration

In this configuration a single S,G of 232.0.0.20 with a source of 104.14.1.2 is mapped to Tree-SID treesid-1 for distribution across the network.

router pim address-family ipv4 interface Loopback0 enable ! interface Bundle-Ether111 enable ! interface Bundle-Ether112 enable ! interface TenGigE0/0/0/16 enable ! sr-p2mp-policy treesid-1 static-group 232.0.0.20 104.14.1.2 !!

Multicast Routing Configuration

multicast-routing address-family ipv4 interface all enable mdt static segment-routing ! address-family ipv6 mdt static segment-routing ! !

Static Tree-SID Receiver Node Multicast Configuration

Global Routing Table Multicast

PIM Configuration

router pim address-family ipv4 rp-address 100.0.0.1 ! !!

On the router connected to the receivers, configure the address family to use the Tree-SID for static S,G mapping.

multicast-routing address-family ipv4 mdt source Loopback0 rate-per-route interface all enable static sr-policy Tree-SID-GRT mdt static segment-routing accounting per-prefix address-family ipv6 mdt source Loopback0 rate-per-route interface all enable static sr-policy Tree-SID-GRT mdt static segment-routing account per-prefix !!

Multicast Routing Configuration

multicast-routing address-family ipv4 interface all enable static sr-policy treesid-1 ! address-family ipv6 static sr-policy treesid-1 ! !

mVPN Multicast Configuration

PIM Configuration

In this configuration, we are mapping the PIM RP to the TREESID source

router pim vrf TREESID address-family ipv4 rp-address 100.0.0.1 ! !!

Multicast Routing Configuration

On the PE connected to the receivers, within the VRF associated with the Tree-SID SR Policy, enable the Tree-SID for static mapping of S,G multicast.

multicast-routing vrf TREESID address-family ipv4 interface all enable static sr-policy treesid-1 ! address-family ipv6 static sr-policy treesid-1 ! !

Tree-SID Verification on PCE

You can view the end to end path using the “show pce lsp p2mp” command.

RP/0/RP0/CPU0:XTC-ACCESS1-PHY#show pce lsp p2mpWed Sep 2 19:31:50.745 UTCTree: treesid-1 Label: 18600 Operational: up Admin: up Transition count: 1 Uptime: 00:06:39 (since Wed Sep 02 19:25:11 UTC 2020) Source: 100.0.0.1 Destinations: 100.0.2.53, 100.0.2.52 Nodes: Node[0]: 100.0.2.3 (AG3) Role: Transit Hops: Incoming: 18600 CC-ID: 1 Outgoing: 18600 CC-ID: 1 (10.23.253.1) Outgoing: 18600 CC-ID: 1 (10.23.252.0) Node[1]: 100.0.2.1 (PA3) Role: Transit Hops: Incoming: 18600 CC-ID: 2 Outgoing: 18600 CC-ID: 2 (10.21.23.1) Node[2]: 100.0.0.3 (PE3) Role: Transit Hops: Incoming: 18600 CC-ID: 3 Outgoing: 18600 CC-ID: 3 (10.3.21.1) Node[3]: 100.0.0.5 (P1) Role: Transit Hops: Incoming: 18600 CC-ID: 4 Outgoing: 18600 CC-ID: 4 (10.3.5.0) Node[4]: 100.0.0.7 (P3) Role: Transit Hops: Incoming: 18600 CC-ID: 5 Outgoing: 18600 CC-ID: 5 (10.5.7.0) Node[5]: 100.0.1.1 (NCS540-PA1) Role: Transit Hops: Incoming: 18600 CC-ID: 6 Outgoing: 18600 CC-ID: 6 (10.1.7.1) Node[6]: 100.0.0.1 (PE1) Role: Ingress Hops: Incoming: 18600 CC-ID: 7 Outgoing: 18600 CC-ID: 7 (10.1.11.1) Node[7]: 100.0.2.53 (A-PE8) Role: Egress Hops: Incoming: 18600 CC-ID: 8 Node[8]: 100.0.2.52 (A-PE7) Role: Egress Hops: Incoming: 18600 CC-ID: 9

Multicast distribution using fully dynamic Tree-SID

In this example we will use dynamic source/receiver discovery using BGP and PCEP signaling to create the SR Tree-SID multicast distribution trees.

Please see https://www.cisco.com/c/en/us/td/docs/routers/asr9000/software/asr9k-r7-5/segment-routing/configuration/guide/b-segment-routing-cg-asr9000-75x/configure-sr-tree-sid.html for for full descriptions of configuration and optional parameters.

Note: There MUST be a BGP route to the source PE to satisfy the Tree-SID RPF check on receiver nodes. It is recommended for multicast to use the IPv4/IPv6 Multicast address family to distribute source information. Please see the section Multicast Source Distribution using BGP Multicast AFI/SAFI

PE BGP Configuration

The following is used to enable the IPv4/IPV6 MVPN AFI/SAFI globally. They address families are also added to the SvRR neighbor group.

router bgp 100 address-family ipv4 mvpn ! address-family ipv6 mvpn !neighbor-group SvRR remote-as 100 update-source Loopback0 address-family ipv4 unicast ! address-family vpnv4 unicast soft-reconfiguration inbound always ! address-family vpnv6 unicast soft-reconfiguration inbound always ! address-family ipv4 mvpn soft-reconfiguration inbound always ! address-family ipv6 mvpn soft-reconfiguration inbound always ! address-family l2vpn evpn soft-reconfiguration inbound always ! !

PE Multicast Routing Configuration

Note the new configuration specific to SR auto-discovery and the color specified for the default MDT. The same configuration is used on both source and receiver PE routers.

div class="highlighter-rouge">multicast-routing address-family ipv4 interface Loopback0 enable ! mdt source Loopback0 interface all enable ! address-family ipv6 interface all enable ! vrf tree-sid address-family ipv4 mdt source Loopback0 interface all enable bgp auto-discovery segment-routing ! mdt default segment-routing mpls color 80 ! !

PE PIM Configuration

The PIM configuration requires the following route-policy be defined.

route-policy sr-p2mp-core-tree set core-tree sr-p2mpend-policy

router pim address-family ipv4 interface Loopback0 enable ! ! vrf tree-sid address-family ipv4 rpf topology route-policy sr-p2mp-core-tree mdt c-multicast-routing bgp ! multipath ssm range ssm

Hierarchical Services Examples

Figure 11: Hierarchical Services Table

L3VPN – Single-Homed EVPN-VPWS, MP-BGP VPNv4/6 with Pseudowire-Headend (PWHE)

Figure 12: L3VPN – Single-Homed EVPN-VPWS, MP-BGP VPNv4/6 with Pseudowire-Headend (PWHE) Control Plane

Access Routers: Cisco NCS 540, 5500, 560 IOS-XR, ASR 920 IOS-XE

1. Operator: New EVPN-VPWS instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR

1. Operator: New EVPN-VPWS instance via CLI or NSO

2. Provider Edge Router: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L3VPN instance (VPNv4/6) together with Pseudowire-Headend (PWHE) via CLI or NSO

4. Provider Edge Router: Path to remote PE is known via CORE-ISIS IGP.

Access Router Service Provisioning (IOS-XR):

VLAN based service configuration

l2vpn xconnect group evpn-vpws-l3vpn-PE1 p2p L3VPN-VRF1 interface TenGigE0/0/0/5.501 neighbor evpn evi 13 target 501 source 501 ! ! !interface TenGigE0/0/0/5.501 l2transport encapsulation dot1q 501 rewrite ingress tag pop 1 symmetric

Port based service configuration

l2vpn xconnect group evpn-vpws-l3vpn-PE1 p2p odn-1 interface TenGigE0/0/0/5 neighbor evpn evi 13 target 502 source 502 ! ! !! interface TenGigE0/0/0/5 l2transport

Access Router Service Provisioning (IOS-XE):

VLAN based service configuration

l2vpn evpn instance 14 point-to-point vpws context evpn-pe4-pe1 service target 501 source 501 member GigabitEthernet0/0/1 service-instance 501 !interface GigabitEthernet0/0/1 service instance 501 ethernet encapsulation dot1q 501 rewrite ingress tag pop 1 symmetric ! 

Port based service configuration

l2vpn evpn instance 14 point-to-point vpws context evpn-pe4-pe1 service target 501 source 501 member GigabitEthernet0/0/1 service-instance 501 !interface GigabitEthernet0/0/1 service instance 501 ethernet encapsulation default

Provider Edge Router Service Provisioning (IOS-XR):

VRF configuration

vrf L3VPN-ODNTE-VRF1 address-family ipv4 unicast import route-target 100:501 ! export route-target 100:501 ! ! address-family ipv6 unicast import route-target 100:501 ! export route-target 100:501 ! !

BGP configuration

router bgp 100 vrf L3VPN-ODNTE-VRF1 rd 100:501 address-family ipv4 unicast redistribute connected ! address-family ipv6 unicast redistribute connected ! !

PWHE configuration

interface PW-Ether1 vrf L3VPN-ODNTE-VRF1 ipv4 address 10.13.1.1 255.255.255.0 ipv6 address 1000:10:13::1/126 attach generic-interface-list PWHE!

EVPN VPWS configuration towards Access PE

l2vpn xconnect group evpn-vpws-l3vpn-A-PE3 p2p L3VPN-ODNTE-VRF1 interface PW-Ether1 neighbor evpn evi 13 target 501 source 501 !

Figure 13: L3VPN – Single-Homed EVPN-VPWS, MP-BGP VPNv4/6 with Pseudowire-Headend (PWHE) Data Plane

L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4 with Anycast IRB

Figure 14: L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4 with Anycast IRB Control Plane

Access Routers: Cisco NCS5501-SE IOS-XR or Cisco ASR920 IOS-XE

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR (Same on both PE routers in same location PE1/2 and PE3/4)

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Provider Edge Routers: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L3VPN instance (VPNv4/6) together with Anycast IRB via CLI or NSO

4. Provider Edge Routers: Path to remote PEs is known via CORE-ISIS IGP.

Access Router Service Provisioning (IOS-XR):

VLAN based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2.1 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !interface TenGigE0/0/0/2.1 l2transport encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric !! l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word !

Port based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !interface TenGigE0/0/0/2 l2transport !! l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word !

Access Router Service Provisioning (IOS-XE):

VLAN based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Port based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation default xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Provider Edge Routers Service Provisioning (IOS-XR):

cef adjacency route override rib

AnyCast Loopback configuration

interface Loopback100 description Anycast ipv4 address 100.100.100.12 255.255.255.255!router isis ACCESS interface Loopback100 address-family ipv4 unicast prefix-sid index 1012 n-flag-clear 

L2VPN configuration

l2vpn bridge group Static-VPWS-H-L3VPN-IRB bridge-domain VRF1 neighbor 100.0.1.50 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! neighbor 100.0.1.51 pw-id 4001 mpls static label local 4001 remote 4001 pw-class static-pw-h-l3vpn-class ! routed interface BVI1 split-horizon group core ! evi 12001 ! !

EVPN configuration

evpn evi 12001 ! advertise-mac ! virtual neighbor 100.0.1.50 pw-id 5001 ethernet-segment identifier type 0 12.00.00.00.00.00.50.00.01

Anycast IRB configuration

interface BVI1 host-routing vrf L3VPN-AnyCast-ODNTE-VRF1 ipv4 address 12.0.1.1 255.255.255.0 mac-address 12.0.1 load-interval 30

VRF configuration

vrf L3VPN-AnyCast-ODNTE-VRF1 address-family ipv4 unicast import route-target 100:10001 ! export route-target 100:10001 ! !!

BGP configuration

router bgp 100 vrf L3VPN-AnyCast-ODNTE-VRF1 rd auto address-family ipv4 unicast redistribute connected ! !

Figure 15: L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4/6 with Anycast IRB Datal Plane

L2/L3VPN – Anycast Static Pseudowire (PW), Multipoint EVPN with Anycast IRB

Figure 16: L2/L3VPN – Anycast Static Pseudowire (PW), Multipoint EVPN with Anycast IRB Control Plane

Access Routers: Cisco NCS 540, 560, 5500 IOS-XR or Cisco ASR920 IOS-XE

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Access Router: Path to PE Router is known via ACCESS-ISIS IGP.

Provider Edge Routers: Cisco ASR9000 IOS-XR (Same on both PE routers in same location PE1/2 and PE3/4)

1. Operator: New Static Pseudowire (PW) instance via CLI or NSO

2. Provider Edge Routers: Path to Access Router is known via ACCESS-ISIS IGP.

3. Operator: New L2VPN Multipoint EVPN instance together with Anycast IRB via CLI or NSO (Anycast IRB is optional when L2 and L3 is required in same service instance)

4. Provider Edge Routers: Path to remote PEs is known via CORE-ISIS IGP.

Please note that provisioning on Access and Provider Edge routers is same as in “L3VPN – Anycast Static Pseudowire (PW), MP-BGP VPNv4/6 with Anycast IRB”. In this use case there is BGP EVPN instead of MP-BGP VPNv4/6 in the core.

Access Router Service Provisioning (IOS-XR):

VLAN based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2.1 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !interface TenGigE0/0/0/2.1 l2transport encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric!l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word !

Port based service configuration

l2vpn xconnect group Static-VPWS-PE12-H-L3VPN-AnyCast p2p L3VPN-VRF1 interface TenGigE0/0/0/2 neighbor ipv4 100.100.100.12 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! !!interface TenGigE0/0/0/2 l2transport!l2vpn pw-class static-pw-h-l3vpn-class encapsulation mpls control-word

Access Router Service Provisioning (IOS-XE):

VLAN based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation dot1q 1 rewrite ingress tag pop 1 symmetric xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Port based service configuration

interface GigabitEthernet0/0/5 no ip address media-type auto-select negotiation auto service instance 1 ethernet encapsulation default xconnect 100.100.100.12 4001 encapsulation mpls manual mpls label 4001 4001 mpls control-word !

Provider Edge Routers Service Provisioning (IOS-XR):

cef adjacency route override rib

AnyCast Loopback configuration

interface Loopback100 description Anycast ipv4 address 100.100.100.12 255.255.255.255!router isis ACCESS interface Loopback100 address-family ipv4 unicast prefix-sid index 1012

L2VPN Configuration

l2vpn bridge group Static-VPWS-H-L3VPN-IRB bridge-domain VRF1 neighbor 100.0.1.50 pw-id 5001 mpls static label local 5001 remote 5001 pw-class static-pw-h-l3vpn-class ! neighbor 100.0.1.51 pw-id 4001 mpls static label local 4001 remote 4001 pw-class static-pw-h-l3vpn-class ! routed interface BVI1 split-horizon group core ! evi 12001 ! !

EVPN configuration

evpn evi 12001 ! advertise-mac ! ! virtual neighbor 100.0.1.50 pw-id 5001 ethernet-segment identifier type 0 12.00.00.00.00.00.50.00.01

Anycast IRB configuration

interface BVI1 host-routing vrf L3VPN-AnyCast-ODNTE-VRF1 ipv4 address 12.0.1.1 255.255.255.0 mac-address 12.0.1 load-interval 30!

VRF configuration

vrf L3VPN-AnyCast-ODNTE-VRF1 address-family ipv4 unicast import route-target 100:10001 ! export route-target 100:10001 ! !!

BGP configuration

router bgp 100 vrf L3VPN-AnyCast-ODNTE-VRF1 rd auto address-family ipv4 unicast redistribute connected ! ! 

Figure 17: L2/L3VPN – Anycast Static Pseudowire (PW), Multipoint EVPN with Anycast IRB Data Plane

Remote PHY CIN Implementation

Summary

Detail can be found in the CST high-level design guide for design decisions, this section will provide sample configurations.

Sample QoS Policies

The following are usable policies but policies should be tailored for specific network deployments.

Class maps

Class maps are used within a policy map to match packet criteria for further treatment

class-map match-any match-ef-exp5 description High priority, EF match dscp 46 match mpls experimental topmost 5 end-class-map!class-map match-any match-cs5-exp4 description Second highest priority match dscp 40 match mpls experimental topmost 4 end-class-map!class-map match-any match-video-cs4-exp2 description Video match dscp 32 match mpls experimental topmost 2 end-class-map!class-map match-any match-cs6-exp6 description Highest priority control-plane traffic match dscp cs6 match mpls experimental topmost 6 end-class-map!class-map match-any match-qos-group-1 match qos-group 1 end-class-map!class-map match-any match-qos-group-2 match qos-group 2 end-class-map!class-map match-any match-qos-group-3 match qos-group 3 end-class-map!class-map match-any match-qos-group-6 match qos-group 3 end-class-map!class-map match-any match-traffic-class-1 description "Match highest priority traffic-class 1" match traffic-class 1 end-class-map!class-map match-any match-traffic-class-2 description "Match high priority traffic-class 2" match traffic-class 2 end-class-map!class-map match-any match-traffic-class-3 description "Match medium traffic-class 3" match traffic-class 3 end-class-map!class-map match-any match-traffic-class-6 description "Match video traffic-class 6" match traffic-class 6 end-class-map

RPD and DPIC interface policy maps

These are applied to all interfaces connected to cBR-8 DPIC and RPD devices.

Note: Egress queueing maps are not supported on L3 BVI interfaces

RPD/DPIC ingress classifier policy map

policy-map rpd-dpic-ingress-classifier class match-cs6-exp6 set traffic-class 1 set qos-group 1 ! class match-ef-exp5 set traffic-class 2 set qos-group 2 ! class match-cs5-exp4 set traffic-class 3 set qos-group 3 ! class match-video-cs4-exp2 set traffic-class 6 set qos-group 6 ! class class-default set traffic-class 0 set dscp 0 set qos-group 0 ! end-policy-map!

P2P RPD and DPIC egress queueing policy map

policy-map rpd-dpic-egress-queuing class match-traffic-class-1 priority level 1 queue-limit 500 us ! class match-traffic-class-2 priority level 2 queue-limit 100 us ! class match-traffic-class-3 priority level 3 queue-limit 500 us ! class match-traffic-class-6 priority level 6 queue-limit 500 us ! class class-default queue-limit 250 ms ! end-policy-map!

Core QoS

Please see the general QoS section for core-facing QoS configuration

CIN Timing Configuration

Please see the G.8275.1 and G.8275.2 timing configuration guides in this document for configuring G.8275.2 on downstream RPD interfaces. Starting in CST 4.0, PTP can be enabled on either physical L3 interfaces or BVI interfaces. PTP is not supported on Bundle Ethernet interfaces.
Starting in CST 4.0 it is recommended to use G.8275.1 end to end across the timing domain, and utilize G.8275.2 on specific interfaces using the PTP Multi-Profile configuration outlined in this document. G.8275.1 allows the use of Bundle Ethernet interfaces within the CIN network.

PTP Messaging Rates

The following are recommended rate values to be used for PTP messaging.

Example CBR-8 RPD DTI Profile

ptp r-dti 4 profile G.8275.2 ptp-domain 60 clock-port 1 clock source ip 192.168.3.1 sync interval -4 announce timeout 5 delay-req interval -4

Multicast configuration

Summary

We present two different configuration options based on either native multicast deployment or the use of a L3VPN to carry Remote PHY traffic. The L3VPN option shown uses Label Switched Multicast profile 14 (partitioned mLDP) however profile 6 could also be utilized.

Global multicast configuration - Native multicast

On CIN aggregation nodes all interfaces should have multicast enabled.

multicast-routing address-family ipv4 interface all enable ! address-family ipv6 interface all enable enable !

Global multicast configuration - LSM using profile 14

On CIN aggregation nodes all interfaces should have multicast enabled.

vrf VRF-MLDP address-family ipv4 mdt source Loopback0 rate-per-route interface all enable accounting per-prefix bgp auto-discovery mldp ! mdt partitioned mldp ipv4 p2mp mdt data 100 ! !

PIM configuration - Native multicast

PIM should be enabled for IPv4/IPv6 on all core facing interfaces

router pim address-family ipv4 interface Loopback0 enable ! interface TenGigE0/0/0/6 enable ! interface TenGigE0/0/0/7 enable ! !

PIM configuration - LSM using profile 14

The PIM configuration is utilized even though no PIM neighbors may be connected.

route-policy mldp-partitioned-p2mp set core-tree mldp-partitioned-p2mpend-policy!router pim address-family ipv4 interface Loopback0 enable vrf rphy-vrf address-family ipv4 rpf topology route-policy mldp-partitioned-p2mp mdt c-multicast-routing bgp ! !

IGMPv3/MLDv2 configuration - Native multicast

Interfaces connected to RPD and DPIC interfaces should have IGMPv3 and MLDv2 enabled

router igmp interface BVI100 version 3 ! interface TenGigE0/0/0/25 version 3 !!router mld interface BVI100 version 2 interface TenGigE0/0/0/25 version 3 ! !

IGMPv3/MLDv2 configuration - LSM profile 14

Interfaces connected to RPD and DPIC interfaces should have IGMPv3 and MLDv2 enabled as needed

router igmp vrf rphy-vrf interface BVI101 version 3 ! interface TenGigE0/0/0/15 ! !!router mld vrf rphy-vrf interface TenGigE0/0/0/15 version 2 ! !!

IGMPv3 / MLDv2 snooping profile configuration (BVI aggregation)

In order to limit L2 multicast replication for specific groups to only interfaces with interested receivers, IGMP and MLD snooping must be enabled.

igmp snooping profile igmp-snoop-1!mld snooping profile mld-snoop-1!

RPD DHCPv4/v6 relay configuration

In order for RPDs to self-provision DHCP relay must be enabled on all RPD-facing L3 interfaces. In IOS-XR the DHCP relay configuration is done in its own configuration context without any configuration on the interface itself.

Native IP / Default VRF

dhcp ipv4 profile rpd-dhcpv4 relay helper-address vrf default 10.0.2.3 ! interface BVI100 relay profile rpd-dhcpv4!dhcp ipv6 profile rpd-dhcpv6 relay helper-address vrf default 2001:10:0:2::3 iana-route-add source-interface BVI100 ! interface BVI100 relay profile rpd-dhcpv6

RPHY L3VPN

In this example it is assumed the DHCP server exists within the rphy-vrf VRF, if it does not then additional routing may be necessary to forward packets between VRFs.

dhcp ipv4 vrf rphy-vrf relay profile rpd-dhcpv4-vrf profile rpd-dhcpv4-vrf relay helper-address vrf rphy-vrf 10.0.2.3 relay information option allow-untrusted ! inner-cos 5 outer-cos 5 interface BVI101 relay profile rpd-dhcpv4-vrf interface TenGigE0/0/0/15 relay profile rpd-dhcpv4-vrf!

cBR-8 DPIC interface configuration without Link HA

Without link HA the DPIC port is configured as a normal physical interface

interface TenGigE0/0/0/25 description .. Connected to cbr8 port te1/1/0 service-policy input rpd-dpic-ingress-classifier service-policy output rpd-dpic-egress-queuing ipv4 address 4.4.9.101 255.255.255.0 ipv6 address 2001:4:4:9::101/64 carrier-delay up 0 down 0 load-interval 30

cBR-8 DPIC interface configuration with Link HA

When using Link HA faster convergence is achieved when each DPIC interface is placed into a BVI with a statically assigned MAC address. Each DPIC interface is placed into a separate bridge-domain with a unique BVI L3 interface. The same MAC address should be utilized on all BVI interfaces. Convergence using BVI interfaces is <50ms, L3 physical interfaces is 1-2s.

Even DPIC port CIN interface configuration

interface TenGigE0/0/0/25 description "Connected to cBR8 port Te1/1/0" lldp ! carrier-delay up 0 down 0 load-interval 30 l2transport !!l2vpn bridge group cbr8 bridge-domain port-ha-0 interface TenGigE0/0/0/25 ! routed interface BVI500 ! ! ! interface BVI500 description "BVI for cBR8 port HA, requires static MAC" service-policy input rpd-dpic-ingress-classifier ipv4 address 4.4.9.101 255.255.255.0 ipv6 address 2001:4:4:9::101/64 mac-address 8a.9698.64 load-interval 30!

Odd DPIC port CIN interface configuration

interface TenGigE0/0/0/26 description "Connected to cBR8 port Te1/1/1" lldp ! carrier-delay up 0 down 0 load-interval 30 l2transport !!l2vpn bridge group cbr8 bridge-domain port-ha-1 interface TenGigE0/0/0/26 ! routed interface BVI501 ! ! ! interface BVI501 description "BVI for cBR8 port HA, requires static MAC" service-policy input rpd-dpic-ingress-classifier ipv4 address 4.4.9.101 255.255.255.0 ipv6 address 2001:4:4:9::101/64 mac-address 8a.9698.64 load-interval 30!

cBR-8 Digital PIC Interface Configuration

interface TenGigE0/0/0/25 description .. Connected to cbr8 port te1/1/0 service-policy input rpd-dpic-ingress-classifier service-policy output rpd-dpic-egress-queuing ipv4 address 4.4.9.101 255.255.255.0 ipv6 address 2001:4:4:9::101/64 carrier-delay up 0 down 0 load-interval 30

RPD interface configuration

P2P L3

In this example the interface has PTP enabled towards the RPD

interface TeGigE0/0/0/15 description To RPD-1 mtu 9200 ptp profile g82752_master_v4 ! service-policy input rpd-dpic-ingress-classifier service-policy output rpd-dpic-egress-queuing ipv4 address 192.168.2.0 255.255.255.254 ipv6 address 2001:192:168:2::0/127 ipv6 enable !

BVI

l2vpn bridge group rpd bridge-domain rpd-1 mld snooping profile mld-snoop-1 igmp snooping profile igmp-snoop-1 interface TenGigE0/0/0/15 ! interface TenGigE0/0/0/16 ! interface TenGigE0/0/0/17 ! routed interface BVI100 ! ! ! !!interface BVI100 description ... to downstream RPD hosts ptp profile g82752_master_v4 ! service-policy input rpd-dpic-ingress-classifier ipv4 address 192.168.2.1 255.255.255.0 ipv6 address 2001:192:168:2::1/64 ipv6 enable !

RPD/DPIC agg device IS-IS configuration

The standard IS-IS configuration should be used on all core interfaces with the addition of specifying all DPIC and RPD connected as IS-IS passive interfaces. Using passive interfaces is preferred over redistributing connected routes. This configuration is needed for reachability between DPIC and RPDs across the CIN network.

router isis ACCESS interface TenGigE0/0/0/25 passive address-family ipv4 unicast ! address-family ipv6 unicast

Additional configuration for L3VPN Design

Global VRF Configuration

This configuration is required on all DPIC and RPD connected routers as well as ancillary elements communicating with Remote PHY elements

vrf rphy-vrf address-family ipv4 unicast import route-target 100:5000 ! export route-target 100:5000 ! ! address-family ipv6 unicast import route-target 100:5000 ! export route-target 100:5000 ! !

BGP Configuration

This configuration is required on all DPIC and RPD connected routers as well as ancillary elements communicating with Remote PHY elements

router bgp 100 vrf rphy-vrf rd auto address-family ipv4 unicast label mode per-vrf redistribute connected ! address-family ipv6 unicast label mode per-vrf redistribute connected ! address-family ipv4 mvpn ! address-family ipv6 mvpn ! !

cBR-8 Segment Routing Configuration

In the CST 4.0 design we introduce Segment Routing on the cBR-8. Configuration of SR on the cBR-8 follows the configuration on other IOS-XE devices. This configuration guide covers only IGP SR-MPLS, and not SR-TE configuration. This allows the cBR-8 to send/receive traffic from other SR-MPLS nodes within the same IGP domain. The cBR-8 can also utilize these paths for BGP next-hop resolution for Global Routing Table (GRT) and BSOD L2VPN/L3VPN services. The following example configuration is for the SUP connection via IS-IS to the provider network, SR is not supported on DPIC interfaces.

IS-IS Configuration

router isis access net 49.0001.0010.0000.0013.00 is-type level-2-only router-id Loopback0 authentication mode md5 level-1 authentication mode md5 level-2 authentication key-chain ISIS-KEY level-1 authentication key-chain ISIS-KEY level-2 metric-style wide fast-flood 10 set-overload-bit on-startup 120 max-lsp-lifetime 65535 lsp-refresh-interval 65000 spf-interval 5 50 200 prc-interval 5 50 200 lsp-gen-interval 5 5 200 log-adjacency-changes segment-routing mpls segment-routing prefix-sid-map advertise-local fast-reroute per-prefix level-2 all fast-reroute ti-lfa level-2 passive-interface Bundle1 passive-interface Loopback0 ! address-family ipv6 multi-topology exit-address-family mpls traffic-eng router-id Loopback0 mpls traffic-eng level-2

Segment Routing Configuration

segment-routing mpls ! set-attributes address-family ipv4 sr-label-preferred exit-address-family ! global-block 16000 32000 ! connected-prefix-sid-map address-family ipv4 1.0.0.13/32 index 213 range 1 exit-address-family !!

Interface Configuration

The connected prefix map is used to advetise the Loopback0 interface as a SR Node SID.

interface TenGigabitEthernet4/1/6 description "Connected to PE4 TenGigE 0/0/0/19" ip address 4.1.6.1 255.255.255.0 ip router isis access load-interval 30 cdp enable ipv6 address 2001:4:1:6::1/64 ipv6 router isis access mpls ip mpls traffic-eng tunnels isis circuit-type level-2-only isis network point-to-point isis authentication mode md5 isis authentication key-chain ISIS-NCS isis csnp-interval 10 level-1 isis csnp-interval 10 level-2 hold-queue 400 in

Cloud Native Broadband Network Gateway (cnBNG)

See the high level design for more information on Cisco cnBNG solution. The following covers the configuration of the User Plane router, in this case an ASR 9000 router.

The following configuring is used for a deployment using IPoE subscriber sessions. The configuration of some external elements such as the RADIUS authentication server are outside the scope of this document. The cnBNG control plane software deployment is also out of scope for this document, please see the cnBNG documentation located at:

interface Loopback10 ipv6 enable !cnbng-nal location 0/RSP0/CPU0 hostidentifier ASR9k-1 !! up-server ip should be the ip of UP interface which will be used as source for SCi communication up-server ipv4 113.1.1.1 vrf default !! cp-server ip is the IP of UDP Proxy configuration cp-server primary ipv4 113.1.1.2 auto-loopback vrf default interface Loopback10 primary-address 1.1.1.1 ! ! !! retry-count specifies how many times UP should retry the connection with CP before declaring CP as dead cp-association retry-count 10 secondary-address-update enable!dhcp ipv4 profile cnbng_v4 cnbng ! interface Bundle-Ether12.101 cnbng profile cnbng_v4!dhcp ipv6 profile cnbng_v6 cnbng ! interface Bundle-Ether12.101 cnbng profile cnbng_v6! interface Bundle-Ether12.101 ipv4 point-to-point ipv4 unnumbered Loopback10 ipv6 address 2001::1/64 ipv6 enable load-interval 30 encapsulation dot1q 101 ipsubscriber ipv4 l2-connected initiator dhcp ! ipv6 l2-connected initiator dhcp

Pseudowire Headend Configuration In this use case subscribers are tunneled to the User Plane using EVPN-VPWS from a remote access node.

interface PW-Ether2000 mtu 1518 ipv4 address 17.1.1.1 255.255.255.0 attach generic-interface-list PWHE!interface PW-Ether2000.2000 ipv4 address 182.168.10.1 255.255.255.252 ipv6 address 2000:111:1::1:1/64 ipv6 enable service-policy type control subscriber IPoE_PWHE1 encapsulation dot1q 2000 ipsubscriber ipv4 l2-connected initiator dhcp ! ipsubscriber ipv6 l2-connected initiator dhcp !!dhcp ipv6 profile ipoev6_proxy proxy helper-address vrf default 2001:12:3::2 source-interface Loopback0 ! interface PW-Ether2000.2000 proxy profile ipoev6_proxy !!l2vpn logging pseudowire ! xconnect group pwhe-bng p2p pwhe-bng1 interface PW-Ether2000 neighbor evpn evi 40 target 900 source 900

Summary

This is not an exhaustive list of IOS-XR model-driven telemetry sensor paths, but gives some basic paths used to monitor a Converged SDN Transport deployment. Each sensor path may have its own cadence of collection and transmission, but it’s recommended to not use values less than 60s when using many sensor paths.

Device inventory and monitoring

Interface Data

LLDP Monitoring

Aggregate bundle information (use interface models for interface counters)

PTP and SyncE Information

BGP Information

IS-IS Information

Routing protocol RIB information

BGP RIB information

It is not recommended to monitor these paths using MDT with large tables

Routing policy Information

Ethernet CFM

EVPN Information

Per-Interface QoS Statistics Information

Per-Policy, Per-Interface, Per-Class statistics

See sensor path name for detailed information on data leafs

L2VPN Information

L3VPN Information

SR-PCE PCC and SR Policy Information

MPLS performance measurement

mLDP Information

ACL Information