User's Manual

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(11) Use the following router configuration command to disable nexthop treatment and use the
local IP address of this BGP connection to replace the nexthop address of the outcoming
routes.
Command Purpose
neighbor
{ip-address | peer-group-name}
next-
hop-self
Disable the nexthop treatment while carrying out
BGP neighbour update.
Using this command to configure will enable the current router to inform itself to be the nexthop of the route.
So, other BGP neighbours will forward packets to this network to the current router. This is very useful in non-
broadcasting network environment, because there exists a path from the current router to the designated
neighbor. But it is not the case in broadcasting network environment, because this will induce unnecessary
extra hops.
61.3.2 Configuring advanced BGP features
1. Use route-map to filter and modify route update
You can use route-map to filter route update and modify parameter attribute based on each neighbour. Route-
map can be applied both on incoming update and outcoming update. Only the routes passing route-map can
be processed while sending or accepting route update.
Route-map supports incoming and outcoming update to match with AS path, community and network number.
AS matching demands the using of command “aspath-list”; the matching based on community demands the
using of command “community-list”, the matching based on the network demands the use of command “ip
access-list”.
Use the following BGP configuration command to configure route-map for filtration and modification of route
update:
Command Purpose
neighbor
{ip-address | peer-group-name}
route-
map
route-map-name
{in | out}
Apply route-map on incoming or outcoming
routes.
For examples of using route-map to filter and modify the route update, please refer to “Examples of BGP route-
map”.
2. Configure aggregate address
Classless inter-domain routing can create aggregate routing (and super network) to minimize the routing table.
You can configure aggregate routing in BGP through redistributing aggregate routes to BGP or through using
conditional aggregate attributes described in the following task list. If there is at least one more detailed record
in BGP routing table, add the aggregate address to the BGP routing table.
Use one or more router configuration commands in the following to create an aggregate address in the routing
table:
Command Purpose
aggregate
network/len
Create aggregate address in BGP routing table.
aggregate
network/len
summary-only
Broadcast summary address only.
aggregate
network/len
route-map
map-name Generate aggregate address according to
conditions designated by route-map.