Segment Routing v6 Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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Segment Routing v6 Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

Dual-stack with SRv6 unicast and IPv4 multicast core

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Explains how a dual-stack core uses SRv6 for unicast traffic and IPv4 for multicast traffic and describes the interoperability benefits, limitations, and configuration requirements.


Dual-stack with SRv6 unicast and IPv4 multicast core is an SRv6 core feature that

  • uses SRv6 for unicast traffic and IPv4 for multicast communication

  • enables a device to simultaneously support multiple Internet Protocol (IP) versions within a network stack, typically IPv4 and IPv6, and

  • allows devices to support both IPv4 and IPv6 unicast addresses concurrently, facilitating the transition to IPv6 while maintaining compatibility with existing IPv4 networks and applications.

Table 1. Feature History Table

Feature Name

Release Information

Feature Description

Dual-stack with SRv6 unicast and IPv4 multicast core

Release 25.4.1

Introduced in this release on: Fixed Systems (8700 [ASIC: K100])(select variants only*)

*This feature is supported on Cisco 8711-48Z-M routers.

Dual-stack with SRv6 unicast and IPv4 multicast core

Release 25.2.1

Introduced in this release on: Fixed Systems (8700 [ASIC: K100]) (select variants only*)

This feature introduces dual-stack support, enabling SRv6 for unicast traffic and IPv4 for multicast communication.

The dual-stack approach combines the strengths of both IPv4 and SRv6 protocols to simplify routing, enhance interoperability, and improve overall network efficiency. SRv6 provides precise control over unicast traffic paths, while IPv4 ensures reliable support for multicast traffic.

*This feature is supported on 8712-MOD-M.

Traffic distribution in dual-stack environments using SRv6 and IPv4

In a dual-stack environment with SRv6 and IPv4 configuration, SRv6 is utilized for unicast traffic, where packets are sent from a single sender to a single receiver. On the other hand, IPv4 is used for multicast communication, which involves sending packets from one sender to multiple receivers.

Benefits of dual-stack with SRv6 unicast and IPv4 multicast

The key benefits of the feature are:

  • Combines the benefits of both IPv4 and SRv6 protocols, by providing a streamlined and optimized network experience for both unicast and multicast communication.

  • Facilitates seamless interoperability between IPv4 and IPv6 protocols.

  • Enables devices to use the optimal protocol for a specific network scenario based on the availability and performance of IPv4 and IPv6 services.

  • Provides a simple solution for data transfer from IPv4 to SRv6 without requiring complex tunneling or translation mechanisms.

  • Preserves the end-to-end connectivity and security of IPv6 while ensuring compatibility with the existing IPv4 infrastructure and applications.


Limitations for dual-stack with SRv6 and IPv4

  • The dual-stack support is available on MVPN GRE-based profiles such as profile 0 and profile 11.

  • The dual-stack supports only SRv6 micro-segments (uSIDs).

  • The dual-stack uses Customer Edge (CE) label allocation for SRv6.


Enable dual-stack with SRv6 unicast and IPv4 multicast core

This section includes only the BGP configuration that is required to enable dual-stack with SRv6 unicast and an IPv4 multicast core.

Procedure

  1. Run the router bgp as-number segment-routing srv6 command to enable SRv6 globally.

    The as-number range is 1–65535.

    Example:

    Router(config)#router bgp 101
    Router(config-bgp)#nsr
    Router(config-bgp)#mvpn
    Router(config-bgp)#bgp router-id 10.10.10.1
    Router(config-bgp)#bgp graceful-restart
    Router(config-bgp)#segment-routing srv6
  2. Run the router bgp command to configure IPv4 for multicast communication.

    Example:

    Router(config-bgp)#address-family ipv4 multicast
    Router(config-bgp-af)#redistribute connected
  3. Run the router bgp command to configure SRv6 for unicast communication.

    The address-family ipv6 unicast and segment-routing srv6 configurations indicate that SRv6 is used for unicast communication.

    Example:

    Router(config-bgp)#address-family ipv6 unicast
    Router(config-bgp-af)#segment-routing srv6
    Router(config-bgp-af)#redistribute connected
    Router(config-bgp-af)#exit
    Router(config-bgp)#address-family ipv6 mvpn
    Router(config-bgp)#address-family ipv4 mvpn
  4. Run the show running-config command to verify the running configuration.

    Example:

    router bgp 101
     nsr
     mvpn
     bgp router-id 10.10.10.1
     bgp graceful-restart
     segment-routing srv6
     !
     address-family ipv4 multicast
      redistribute connected
     !
     address-family ipv6 unicast
      segment-routing srv6
      !
      redistribute connected
     !
     address-family ipv4 mvpn
     !
     address-family ipv6 mvpn
     !
    !