Multicast and Routing Guide K/KA/KB.15.15

CAUTION:
• The maximum keepalive interval should be one third of the holdtime and no less than 1 second.
The holdtime is no less than 3 seconds unless it is set to 0.
• Intervals set with the neighbor timers command are preferred to those set with the timers
command.
• If the router has established a neighbor relationship with a peer, you need to reset the BGP
connection to validate the new set timers.
Configuring a large scale BGP network
In a large-scale BGP network, configuration and maintenance become difficult due to large numbers
of BGP peers. To facilitate configuration in this case, you can configure community or route reflector
as needed.
Prerequisites
A BGP community must be configured. Follow these steps.
RemarksUse the command...To do...
configurationEnter the global configuration context
bgp as-numberEnter the BGP context
Enabled by defaultneighbor {ip-address}
send-community
Advertise the community attribute to a
peer
CAUTION: When configuring the BGP community, you must configure a routing policy to define
the community attribute, and then apply the routing policy to the route advertisement.
Configuring a BGP route reflector
Follow these steps to configure a BGP route reflector:
RemarksUse the command...To do...
configurationEnterthe global configuration context
bgp as-numberEnter the BGP context
Enabled by defaultclient-to-client-reflectionConfigure the router as a route
reflector and specify a peer as its
client
Optional. Enabled by default.neighbor {ip-address}
route-reflector-client
Enable route reflection between clients
CAUTION: It is not required to make clients of a route reflector fully meshed. The route reflector
forwards routing information between clients. If clients are fully meshed, you can disable route
reflection between clients to reduce routing costs.
A cluster has only one route reflector, and the router ID is used to identify the cluster. You can
configure multiple route reflectors to improve network stability. In this case, you must specify the
same cluster ID for these route reflectors to avoid routing loops.
Configuring BGP graceful restart (GR)
Perform the following configuration on the GR Restarter and GR Helper respectively.
BGP basic configuration 315