Segment Routing Configuration Guide, Cisco IOS XE 17 - Cisco

• Skip to content
• Skip to search
• Skip to footer

• Cisco.com Worldwide
• Products and Services
• Solutions
• Support
• Learn
• Explore Cisco
• How to Buy
• Partners Home
• Partner Program
• Support
• Tools
• Find a Cisco Partner
• Meet our Partners
• Become a Cisco Partner

• Home
• Support
• Product Support
• Cisco IOS and NX-OS Software
• Cisco IOS XE 17
• Configuration Guides

Segment Routing Configuration Guide, Cisco IOS XE 17 | Access and Edge Routers Bias-Free Language

Bias-Free Language

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.

Book Contents Book Contents

• Read Me First
• Introduction to Segment Routing for the MPLS Dataplane
• Segment Routing with IS-IS v4 Node SID
• IS-IS Link-protection Topology Independent Loop Free Alternate Fast Reroute
• Segment Routing Traffic Engineering With IS-IS
• Segment Routing With OSPFv2 Node SID
• OSPFv2 Link-protection Topology Independent Loop Free Alternate Fast Reroute
• Segment Routing Traffic Engineering With OSPF
• BGP Dynamic Segment Routing Traffic Engineering
• Segment Routing On Demand Next Hop for L3/L3VPN
• Segment Routing On Demand for L2VPN/VPWS
• Fast Convergence Default Optimize
• Routing Information Base Support
• SR-TE On Demand LSP
• Segment Routing MPLS OAM Support
• Using Seamless BFD with Segment Routing
• Using SSPF with Segment Routing
• Dynamic PCC
• SR: PCE Initiated LSPs
• ISIS - SR: uLoop Avoidance
• BGP - SR: BGP Prefix SID Redistribution
• Advertise Maximum SID Depth by IS-IS and OSPF to BGP-LS
• RSVP-TE Protection using Segment Routing Traffic Engineering AutoTunnel
• ISIS Manual Adjacency SID
• OSPF Manual Adjacency SID
• OSPFv2 Segment Routing Strict SPF
• Segment Routing OSPFv2 Microloop Avoidance
• Performance Measurement for Traffic Engineering
• Configure Performance Measurement
• IP Endpoint Delay Measurement and Liveness Monitoring
• SR-TE Per-Flow (Class) ODN and Automated Steering (PCE Delegated)
• Advertisement of Loopback Prefix SIDs of a Border Router in Multiple ISIS Domains
• Traffic Steering by Dropping Invalid Paths
• Configuring the Cisco ISIS Local Unequal Cost Multipath (UCMP)
• Enabling Segment Routing Flexible Algorithm
• L2VPN over SR-TE Preferred Path
• COE-PCE Initiated SR Policy with IGP Autoroute Announce
• DC-PE Router in Cisco ACI to SR-MPLS Hand-off
• Segment Routing over IPv6
• ISIS - SRv6: uLoop Avoidance
• IPv6 Loop-Free Alternate Fast Reroute
• IS-IS SRv6 Link-protection Topology Independent Loop Free Alternate Fast Reroute
• SRv6 Flex-Algo with TI-LFA and uLoop Avoidance
• SRv6 Path MTU Discovery on IOS XE devices
• MVPN ingress replication over SRv6

Search Find Matches in This Book Save Log in to Save Content Translations Available Languages Download Download Options Print

Results

Updated: August 26, 2024

Chapter: L2VPN over SR-TE Preferred Path

Chapter Contents

• L2VPN over SR-TE Preferred Path
• Restrictions
• Configuring L2VPN Traffic Steering Using SR-TE Preferred Path with Flexible Algorithm
• Configuration Example 1: VPWS Psuedowire over SR-TE Preferred Path
• Configuration Example 2: VPWS Psuedowire over SR-TE Preferred Path
• Configuration Example 3: VPLS Psuedowire over SR-TE Preferred Path
• Verification of L2VPN over SR-TE Preferred Path Configuration

Close L2VPN over SR-TE Preferred Path Table 1. Feature History

Feature Name	Release Information	Description
L2VPN Traffic Steering Using SR-TE Preferred Path with Flexible Algorithm	Cisco IOS XE Bengaluru 17.6.1	This feature allows you to configure an SR policy with as the preferred path for a VPWS or VPLS pseudowire, with Flexible Algorithm. VPWS or VPLS pseudowires between same PEs can be routed over different SR policies based on the requirements. Prior to this release, you could only steer the traffic using the SR policy for routing IPv4 traffic to a destination pseudowire (over IGP or BGP-LU).

Virtual Private LAN Services (VPLS) enables enterprises to link together multiple Ethernet-based LANs via the infrastructure provided by their service provider.

VPLS uses the service provider core to join multiple attachment circuits of an enterprise to simulate a virtual bridge. From the enterprise point of view, there is no topology for VPLS. All customer edge (CE) devices appear to connect to a logical bridge emulated by the service provider core.

Prior to Cisco IOS XE Bengaluru Release 17.6.1, L2VPN (VPLS or VPWS) traffic over SR policies could not be steered. You could only steer IPv4 traffic using the SR policy for routing IPv4 traffic to a destination pseudowire (over IGP or BGP-LU).

Now you configure an SR policy as the preferred path for a VPWS or VPLS pseudowire, with Flexible Algorithm. VPWS or VPLS pseudowires between same PEs can also be routed over different SR policies.

Disable Fallback Option

The disable fallback option disables the router from using the default path when the preferred path SR policy goes down.

• Restrictions
• Configuring L2VPN Traffic Steering Using SR-TE Preferred Path with Flexible Algorithm
• Configuration Example 1: VPWS Psuedowire over SR-TE Preferred Path
• Configuration Example 2: VPWS Psuedowire over SR-TE Preferred Path
• Configuration Example 3: VPLS Psuedowire over SR-TE Preferred Path
• Verification of L2VPN over SR-TE Preferred Path Configuration

Restrictions

• You cannot add On-Demand (ODN) policies to the preferred path.

• L2VPN over SR-TE preferred path is only supported on SR Per Destination Policy (PDP); and not on the SR Per-Flow Policy (PFP).

• L2VPN over SR-TE preferred path can only be configured using the pseudowire interface.

• This feature is supported only on IS-IS protocol

Configuring L2VPN Traffic Steering Using SR-TE Preferred Path with Flexible Algorithm

To configure IS-IS with Flex Algo:router isis 1 affinity-map green bit-position 0 affinity-map red bit-position 1 affinity-map yello bit-position 2 flex-algo 128 advertise-definition metric-type delay priority 200 affinity exclude-any name red name yellow ! flex-algo 129 advertise-definition priority 200 affinity exclude-any name green name red interface Tunnel100 isis affinity flex-algo name green ! interface Tunnel101 isis affinity flex-algo name yellow ! interface Tunnel102 isis affinity flex-algo name red segment-routing traffic-eng policy p-2000 color 2000 end-point 10.4.4.4 performance-measurement delay-measurement candidate-paths preference 10 constraints segments dataplane mpls algorithm 128 ! ! ! dynamic To create SR static policy for MPLS label:configure terminal segment-routing traffic-eng segment-list name segment-name index 1 mpls label first hop label index 2 mpls label second hop label ! policy policy-name color color-code end-point destination IP Address candidate-paths preference preference explicit segment-list segment-name constraints segments dataplane mpls You can also create SR static policy for the following:

• MPLS adjacency

• MPLS prefix

L2VPN over SR-TE preferred path can be configured in the following ways:

• Non-Template based Configuration

• Template-based Configuration

Non-template Based Configuration:

• Create Pseudowire

  To create pseudowire:interface pseudowire 1 encapsulation mpls neighbor peer-address vc-id

• Attach Policy Using Preferred Path

  To attach a policy using the preferred path:interface pseudowire1 preferred-path segment-routing traffic-eng policy policy-name [disable-fallback]

Template-based Configuration:

• Create Template Type Pseudowire

  To create template type pseudowire:template type pseudowire name encapsulation mpls preferred-path segment-routing traffic-eng policy name [disable-fallback]

• Attach Policy Using Preferred Path

  To attach a policy using the preferred path:interface pseudowire 1 source template type pseudowire name

Configuration Example 1: VPWS Psuedowire over SR-TE Preferred Path

! interface gi0/0/1 service instance 1000 ethernet encapsulation dot1q 1000 ! template type pseudowire l2vpntest encapsulation mpls preferred-path Segment-Routing traffic-eng policy p106 l2vpn xconnect context l2vpn-test member 10.6.6.6 1000 template l2vpntest member gi0/0/1 service-instance 1000 !

Configuration Example 2: VPWS Psuedowire over SR-TE Preferred Path

! ! interface gi0/0/1 service instance 1000 ethernet encapsulation dot1q 1000 ! template type pseudowire l2vpntest encapsulation mpls preferred-path Segment-Routing traffic-eng policy p106 ! interface pseudowire1000 source template type pseudowire l2vpntest encapsulation mpls neighbor 10.1.1.1 1000 ! l2vpn xconnect context l2vpn-test member pseudowire 1000 member gi0/0/1 service-instance 1000

Configuration Example 3: VPLS Psuedowire over SR-TE Preferred Path

interface gi0/0/1 service instance 1000 ethernet encapsulation dot1q 1000 ! interface pseudowire106 encapsulation mpls neighbor 10.6.6.6 1000 preferred-path Segment-Routing traffic-eng policy p106 ! interface pseudowire104 encapsulation mpls neighbor 10.4.4.4 1000 preferred-path Segment-Routing traffic-eng policy p104 ! l2vpn vfi context VC_1000 vpn id 1000 member pseudowire106 member pseudowire104 ! bridge-domain 1000 member gi0/0/1 service-instance 1000 member vfi VC_1000

Verification of L2VPN over SR-TE Preferred Path Configuration

Use the show segment-routing traffic-eng policy name policy name detail command to verify the policy configuration:Router#show segment-routing traffic-eng policy name CE11-PE12 detail Name: CE11-PE12 (Color: 50 End-point: 10.12.12.12) Owners : CLI Status: Admin: up, Operational: up for 70:04:00 (since 08-17 07:55:36.536) Candidate-paths: Preference 100 (CLI): Explicit: segment-list IntraDomain (active) Weight: 1, Metric Type: TE 16005 16008 16010 Attributes: Binding SID: 20 Allocation mode: dynamic State: Programmed Tunnel ID: 65538 (Interface Handle: 0x20) Per owner configs: CLI Binding SID: dynamic Stats: Packets: 0 Bytes: 0 Event history: Timestamp Client Event type Context: Value ---------------- ------ -------------- ---------: --------- 10-28 04:05:37.028 L2VPN Policy created Name: L2VPN 10-28 04:05:37.048 L2VPN BSID allocated FWD: label 20 10-28 04:05:37.494 L2VPN Client removed Owner: Destroyed 10-28 04:05:37.494 CLI Set colour Colour: 230 10-28 04:05:37.494 CLI Set end point End-point: 12.12.12.12 10-28 04:05:37.496 CLI Set explicit path Path option: IntraDomain 10-28 04:08:22.873 FH Resolution Policy state UP Status: PATH RESOLVED 10-28 04:08:45.630 FH Resolution REOPT triggered Status: REOPTIMIZED Use show mpls l2transport vc 1000 detail command to verify the L2VPN over SR-TE preferred path:Router#show mpls l2transport vc 1000 detail Local interface: VFI VC_1000 vfi up Interworking type is Ethernet Destination address: 10.12.12.12, VC ID: 1000, VC status: up Output interface: tu65538, imposed label stack {16005 16008 16010 32} Preferred path: not configured Default path: active Next hop: 10.168.1.1 Create time: 1w4d, last status change time: 22:50:57 Last label FSM state change time: 22:51:46 Signaling protocol: LDP, peer 10.1.1.1:0 up Targeted Hello: 10.2.2.2(LDP Id) -> 10.1.1.1, LDP is UP Graceful restart: not configured and not enabled Non stop routing: not configured and not enabled Status TLV support (local/remote) : enabled/supported LDP route watch : enabled Label/status state machine : established, LruRru Last local dataplane status rcvd: No fault Last BFD dataplane status rcvd: Not sent Last BFD peer monitor status rcvd: No fault Last local AC circuit status rcvd: No fault Last local AC circuit status sent: No fault Last local PW i/f circ status rcvd: No fault Last local LDP TLV status sent: No fault Last remote LDP TLV status rcvd: No fault Last remote LDP ADJ status rcvd: No fault MPLS VC labels: local 26, remote 21 Group ID: local n/a, remote 16 MTU: local 9000, remote 9000 Remote interface description: MAC Withdraw: sent:0, received:301 Sequencing: receive disabled, send disabled Control Word: On (configured: autosense

Was this Document Helpful?

Yes No Feedback

Contact Cisco

• Open a Support Case
• (Requires a Cisco Service Contract)