Administrator Guide

Configuring BGP aggregate routes
To create an aggregate route entry in the BGP routing table, use the following commands.
The aggregate route is advertised from the autonomous system.
• Enter the router configuration mode and the AS number for the specific BGP routing process.
CONFIG mode
router bgp as-number
• Create an aggregate entry in the BGP routing table.
CONFIG-ROUTER-BGP mode
aggregate—address address-mask
Use the aggregate-address command without any keywords to create an aggregate entry if any specific BGP routes are available
in the specified range.
DellEMC# configure terminal
DellEMC(conf)# router bgp 100
DellEMC(conf-router_bgp)# aggregate-address 10.1.1.0/24
DellEMC(conf-router_bgp)# exit
DellEMC(conf)#
Following is the sample output of show ip bgp command.
DellEMC# show ip bgp
BGP local RIB : Routes to be Added 0, Replaced 0, Withdrawn 0
BGP local router ID is 30.30.30.30
Status codes: s suppressed, S stale, d dampened, h history, * valid, > best
Path source: I - internal, a - aggregate, c - confed-external, r - redistributed
n - network, D - denied, S - stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>r 3.3.3.0/24 0.0.0.0 0 32768 ?
s>r 10.1.1.0/30 0.0.0.0 0 32768 ?
*>r 30.30.30.30/32 0.0.0.0 0 32768 ?
*>a 10.1.1.0/24 0.0.0.0 32768 ?
Suppressing BGP aggregate routes
The routes that are suppressed are not advertised to any of the BGP neighbors. You can suppress the aggregate routes using the
suppress-map or summary-only options in the aggregate-address configuration. To suppress the advertisement of the
aggregate routes using BGP, use the following commands.
• Create an aggregate entry and suppress the advertisement of specific routes to all neighbors.
CONFIG-ROUTER-BGP mode
aggregate—address address-mask summary-only
• Create an aggregate entry and suppress the advertisement of specific routes.
CONFIG-ROUTER-BGP mode
aggregate—address address-mask suppress-map map-name
The suppress-map keyword creates the aggregate route but suppress the advertisement of specified routes. The routes that are
suppressed are not advertised to the neighbors. You can use match clause of route maps to selectively suppress the specific route
from the aggregate routes.
Following is the sample configuration to suppress the advertisement of specific aggregate routes.
DellEMC# configure terminal
DellEMC(conf)# router bgp 100
DellEMC(conf-router_bgp)# aggregate-address 10.1.1.0/24 suppress-map map1
DellEMC(conf-router_bgp)# exit
DellEMC(conf)#
The route-map named map1 can have any action such as permit and sequence number configured, so that the advertisement of
aggregate routes can be suppressed based on the set action in the route-map.
Border Gateway Protocol (BGP)
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