Setup Guide
Conguring BGP Route Reectors
BGP route reectors are intended for ASs with a large mesh; they reduce the amount of BGP control trac.
NOTE: Dell EMC Networking recommends
not
using multipath and add path simultaneously in a route reector.
With route reection congured properly, IBGP routers are not fully meshed within a cluster but all receive routing information.
Congure clusters of routers where one router is a concentration router and the others are clients who receive their updates from the
concentration router.
To congure a route reector, use the following commands.
• Assign a cluster ID or an IP address to a router reector cluster.
CONFIG-ROUTER-BGP mode
bgp cluster-id ip-address | number
– ip-address: IP address as the route reector cluster ID.
– number: A route reector cluster ID as a number from 1 to 4294967295.
You can have multiple clusters in an AS. When a BGP cluster contains only one route reector, the cluster ID is the route reector’s
router ID. For redundancy, a BGP cluster may contain two or more route reectors. Without a cluster ID, the route reector cannot
recognize route updates from the other routes reector within the cluster.
• Congure the local router as a route reector and the specied neighbors or peer group as members of the cluster.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | ipv6-address | peer-group-name} route-reflector-client
When you enter this command for the rst time, the router congures as a route reector and the specied BGP neighbors congure as
clients in the route reector cluster. When you remove all clients of a route reector using the no neighbor route-reflector-
client
command, the router no longer functions as a route reector. When you enable a route reector, Dell EMC Networking OS
automatically enables route reection to all clients. To disable route reection between all clients in this reector, use the no bgp
client-to-client reflection
command in CONFIGURATION ROUTER BGP mode. All clients must be fully meshed before you
disable route reection.
To view a route reector conguration, use the show config command in CONFIGURATION ROUTER BGP mode or the show
running-config bgp
in EXEC Privilege mode.
Enabling Route Flap Dampening
When EBGP routes become unavailable, they “ap” and the router issues both WITHDRAWN and UPDATE notices.
A ap is when a route:
• is withdrawn
• is readvertised after being withdrawn
• has an attribute change
The constant router reaction to the WITHDRAWN and UPDATE notices causes instability in the BGP process. To minimize this instability,
you may congure penalties (a numeric value) for routes that ap. When that penalty value reaches a congured limit, the route is not
advertised, even if the route is up. In Dell EMC Networking OS, that penalty value is 1024. As time passes and the route does not ap, the
penalty value decrements or is decayed. However, if the route aps again, it is assigned another penalty.
The penalty value is cumulative and penalty is added under following cases:
Border Gateway Protocol (BGP)
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