• Author : Ajay Kini

 
 

Ordered Next Hops in FEC Support

Description In a symmetric network topology, for the same ECMP (Equal Cost Multi Path) route programmed at different devices in a switch layer, the various devices can program ECMP next hops in the FEC (Forwarding Equivalence Class) for that route in varying orders. This could result in inconsistent hashing of traffic for those destination routes at the same layer of switches in the network and could be undesired behavior for certain classes of applications. Ordered FEC is an approach to order the next hops in the FEC of a route on the basis of a network-wide device identifier for each...
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Accumulated IGP Metric (AIGP)

Description Accumulated IGP Metric (AIGP) is an optional non-transitive BGP attribute used to carry an IGP metric with BGP route advertisements. The AIGP attribute is useful for tie-breaking in BGP bestpath selection so that routing decisions can be made on the basis of shortest path/lowest IGP cost path amongst multiple BGP paths. This is particularly applicable in scenarios where a single administration is subdivided into multiple Autonomous Systems (AS) each with similar routing policies and the same IGP in use such that the IGP metric for a route can be propagated usefully between the ASes so as to let receiving...
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