• Author : Denis Evoy

 
 

The BGP best-path selection algorithm

Description BGP routing information often contains more than one path to the same destination network. The BGP best-path selection algorithm determines which of these paths should be considered as the best path to that network. The best BGP path (as chosen by the algorithm) is then used as follows: If it is also chosen as the RIB winner (i.e. the winning path from among any other non-BGP paths), it will be installed in the RIB and used to forward traffic to that network. With the multi-agent routing protocol model since EOS-4.23.2, RIB installation can be skipped by using the “bgp...
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Discard unimportable VPN paths

Description In a Service Provider network, a Provider Edge (PE) device learns VPN paths from remote PEs and uses the Route Target extended communities carried by those paths to determine which customer VRF(s) the paths should be imported into (from where they can be subsequently advertised to Customer Edge (CE) devices). In large Service Provider networks, each PE device may learn a significant number of VPN paths even though it might only handle a relatively small number of customer VRFs. As a result, such PE devices are really only interested in a subset of the VPN paths that they receive...
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The BGP best-path selection algorithm

Description BGP routing information often contains more than one path to the same destination network. The BGP best-path selection algorithm determines which of these paths should be considered as the best path to that network. If the best BGP path (as chosen by the algorithm) is also chosen as the winning path from among the other non-BGP paths (if any), it will be installed in the RIB and used to forward traffic to that network. The best BGP path will also be the path that is subsequently advertised to any BGP neighbors. BGP best-path steps When comparing any two paths...
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