• Author : Paulo Panhoto


BGP multicluster route-reflector

Description The route reflector, as described in RFC 4456, is a router allowed to advertise (reflect) iBGP learned routes to other iBGP peers. The peers to a route-reflector can be qualified as clients (whose learned routes can be reflected to all peers) and non-clients (whose learned routes are only reflected to clients). The route reflector and its clients constitute a cluster. To prevent network loops, each cluster is assigned an identifier, namely, the cluster-ID. The cluster-ID is prepended to the path attribute cluster-list whenever a route is reflected. When a path is received and the cluster-list is present, the route...
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RFC 6368 – iBGP as PE-CE Protocol for BGP/MPLS L3 VPNs

Description This is an extension to BGP MPLS VPNs that allows us to use iBGP as the PE-CE protocol. This feature also provides a way to isolate the customer’s network BGP attributes from the SP backbone’s attributes, by saving them into a special attribute called ATTR_SET, code 128. This separation introduces a “route server” model that allows the customer’s BGP path attributes to be stored in the SP backbone along with the VPN-IPv4/v6 paths. This feature is enabled by configuring the AS number of the PE’s VRF to match the CE’s AS number. This will cause the exported paths by...
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Show bgp neighbors history

Description This command stores and displays a list of failed BGP connection attempts for each peer. This may be particularly useful while troubleshooting flappy connections. If dynamic peering is enabled, the failure history will be remembered even after the peers are no longer present. Platform compatibility This feature is supported on all platforms. Configuration Relevant error messages are recorded by default, without any configuration. To clear all messages for a peer or group of peers, though, it is necessary to use the command “clear bgp history”. The syntax for this command is described as: switch#clear bgp [ PEER | PREFIX...
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