Anycast Segments in MPLS based Segment Routing

Document Type Expired Internet-Draft (spring WG)
Authors Pushpasis Sarkar  , Hannes Gredler  , Clarence Filsfils  , Stefano Previdi  , Bruno Decraene  , Martin Horneffer 
Last updated 2020-10-29 (latest revision 2020-04-27)
Replaces draft-psarkar-spring-mpls-anycast-segments
Stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
Expired & archived
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Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Yes
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


Instead of forwarding to a specific device or to all devices in a group, anycast addresses, let network devices forward a packet to (or steer it through) one or more topologically nearest devices in a specific group of network devices. The use of anycast addresses has been extended to the Segment Routing (SR) network, wherein a group of SR-capable devices can represent a anycast address, by having the same Segment Routing Global Block (SRGB) provisioned on all the devices and each one of them advertising the same anycast prefix segment (or Anycast SID). This document describes a proposal for implementing anycast prefix segments in a MPLS-based SR network, without the need to have the same SRGB block (label ranges) provisioned across all the member devices in the group. Each node can be provisioned with a separate SRGB from the label range supported by the specfic hardware platform.


Pushpasis Sarkar (
Hannes Gredler (
Clarence Filsfils (
Stefano Previdi (
Bruno Decraene (
Martin Horneffer (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)