Extended Encoding Scheme for Shared List Link Group (SRLG)

Document Type Expired Internet-Draft (individual)
Authors Zafar Ali  , George Swallow  , Clarence Filsfils  , Ori Gerstel  , Stewart Bryant  , Matt Hartley 
Last updated 2013-08-22 (latest revision 2013-02-18)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


SRLGs play a key role in routing resiliency and capacity planning of multi-domain and multi-layer networks. Notion of SRLG are used to select a backup path that is disjoint from the primary path, to ensure disjointness of circuits and to avoid catastrophic partitioning outages. In the current specifications, SRLG is identified as a 32 bit number that is unique within an IGP domain [RFC4202]. There are many limitations to this approach of encoding SRLGs, especially in a multi-layer network. This draft outlines these limitations and suggests components of extended SRLG encoding scheme to address them.


Zafar Ali (zali@cisco.com)
George Swallow (swallow@cisco.com)
Clarence Filsfils (cfilsfil@cisco.com)
Ori Gerstel (ogerstel@cisco.com)
Stewart Bryant (stbryant@cisco.com)
Matt Hartley (mhartley@cisco.com)

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