BGP Link-State Extensions for BGP-only Networks#

Ketan Talaulikar (independent), Aravind Babu MahendraBabu, Clarence Filsfils, Krishna Swamy (Cisco), Shawn Zandi (LinkedIn), Gaurav Dawra, Muhammad Durrani (Equinix)

• Why: In BGP-only DC/AI fabrics, nodes have no visibility beyond direct neighbors — which blocks LFA/TI-LFA computation, remote protection, and controller TE. This draft is the enabler several other RTGWG/IDR drafts depend on, including the IPFRR-for-AI/ML draft below.
• What: A WG draft (draft-ietf-idr-bgp-ls-bgp-only-fabric-04, adopted by IDR) that lets each BGP speaker advertise its local topology via existing BGP-LS NLRI types (Node, Link, Prefix), giving controllers a full underlay link-state and TE view in networks with no IGP.
• How: Reuses existing BGP-LS descriptors and attribute TLVs (link bandwidth, SR adjacency SIDs, affinities, TE metric, SR prefix SIDs); adds one new BGP Route Type TLV in the Prefix Descriptor. Works via route-reflector distribution to controllers or a centralized BGP-LS collector; the base eBGP underlay is untouched.
• Where applicable: BGP-only fabrics — DC/MSDN per RFC 7938 and emerging AI DC networks. The draft focuses on eBGP single-hop peering; other models not precluded. Implementations in progress; code-point allocation requested. Directly feeds draft-clad-rtgwg-ipfrr-aiml and efficient-remote-protection.