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

PDF

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

IPv4 BGP Global SRv6 services

Want to summarize with AI?

Log in

Explains how SRv6 provides IPv4 global BGP services and describes the endpoint behaviors used to decapsulate and forward IPv4 traffic.


IPv4 BGP global is a BGP service that operates within an IPv4 network, and is supported by SRv6-based services through the implementation of uDX4, uDT4, and uDT46 SRv6 functions at the PE node.

Key concepts

  • IPv4 global BGP: Refers to BGP routing specifically for IPv4 addresses within the global routing table, typically used for internet-wide connectivity rather than within a Virtual Routing and Forwarding (VRF) instance.

  • uDX4, uDT4, and uDT46 SRv6 Functions: These are specific SRv6 Segment Identifiers (SIDs) or behaviors that define how a packet is processed at an SRv6-enabled node.

    • uDX4 (Endpoint with decapsulation and IPv4 lookup): This behavior indicates that the PE node decapsulates the SRv6 header and then performs an IPv4 lookup in its routing table to forward the packet.

    • uDT4 (Endpoint with decapsulation and IPv4 table lookup): This behavior is similar to uDX4, specifically indicating a lookup in an IPv4 routing table.

    • uDT46 (Endpoint with decapsulation and IPv4/IPv6 table lookup): This behavior supports decapsulation and a lookup in either an IPv4 or IPv6 routing table, enabling dual-stack forwarding.


Restrictions of IPv4 BGP Global SRv6 Services

  • SRv6 locator can be assigned globally or under IPv4 unicast address family

  • Equal-Cost Multi-path (ECMP) and Unequal Cost Multipath (UCMP) are supported.

  • BGP, OSPF, Static are supported as PE-CE protocol.

  • BGP route leaking between BGP Global and L3VPN is supported.

  • Starting from Release 7.8.1, Dual-Stack L3 Services (IPv4 BGP global, IPv6 BGP global) are supported.