Advertisement of Segment Routing Policies Using BGP - Link State
RFC 9857, “Advertisement of Segment Routing Policies Using BGP - Link State”, is a Proposed Standard document published in October 2025 by S. Previdi, K. Talaulikar, J. Dong, H. Gredler, J. Tantsura. The canonical text is published by the RFC Editor.
Abstract
This document describes a mechanism used to collect Segment Routing (SR) Policy information that is locally available in a node and advertise it into BGP - Link State (BGP-LS) updates. Such information can be used by external components for path computation, reoptimization, service placement, network visualization, etc.
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
The canonical text of RFC 9857 is hosted at rfc-editor.org. Available in HTML,TXT,PDF,XML.
- RFC 9856 Multicast Source Redundancy in EVPNs
- RFC 9858 Additional Parameter Sets for HSS/LMS Hash-Based Signatures
- RFC 9855 Topology Independent Fast Reroute Using Segment Routing
- RFC 9859 Generalized DNS Notifications
- RFC 9854 AODV-RPL: The Routing Protocol for Low-Power and Lossy Networks Based on Ad Hoc On-Demand Distance Vector Routing
- RFC 9860 Multicast-Only Fast Reroute Based on Topology Independent Loop-Free Alternate Fast Reroute
- RFC 9861 KangarooTwelve and TurboSHAKE
- RFC 9862 Path Computation Element Communication Protocol Extensions for Segment Routing Policy Candidate Paths