Concept Guide
reducing the convergence time. You can congure BGP to congure and advertise aggregated routes. At least one specic route of the
aggregate must be in the routing table for the congured aggregate to become active.
To aggregate routes, use the following command.
AS_SET includes AS_PATH and community information from the routes included in the aggregated route.
• Assign the IP address and mask of the prex to be aggregated.
CONFIG-ROUTER-BGP mode
aggregate-address ip-address mask [advertise-map map-name] [as-set] [attribute-map map-name]
[summary-only] [suppress-map map-name]
– as-set- Specify that the advertised path of this route is an AS_SET.
– summary-only-Create aggregate route and suppress advertisements of specic routes to all neighbors.
– suppress-map map-name-Create aggregate route by suppressing the advertisements of specic routes.
– advertise-map map-name-Create aggregate route by advertising specic routes.
Conguring 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 conguration mode and the AS number for the specic 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 specic BGP routes are available
in the specied range.
Example of conguring aggregate routes using BGP
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BGP local RIB : Routes to be Added 0, Replaced 0, Withdrawn 0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 ?
220
Border Gateway Protocol (BGP)