Reference Guide

1. Assign an AS number in CONFIGURATION mode.
router bgp as-number
2. Enter Address Family mode in ROUTER-BGP mode.
address-family {[ipv4 | ipv6] [unicast]}
3. to aggregate in ROUTER-BGPv4-AF mode.
aggregate-address ip-address mask
Configure aggregate routes
OS10(config)# router bgp 105
OS10(conf-router-bgp-105)# address-family ipv4 unicast
OS10(conf-router-bgpv4-af)# aggregate-address 3.3.0.0/16
View running configuration
OS10(conf-router-bgpv4-af)# do show running-configuration bgp
! Version
! Last configuration change at Jul 27 06:51:17 2016
!
!
router bgp 105
!
address-family ipv4 unicast
aggregate-address 3.3.0.0/16
!
neighbor 32.1.1.2
remote-as 104
no shutdown
!
address-family ipv4 unicast
Confederations
Another way to organize routers within an AS and reduce the mesh for IBGP peers is to configure BGP confederations. As with
route reflectors, Dell EMC recommends BGP confederations only for IBGP peering involving many IBGP peering sessions per
router.
When you configure BGP confederations, you break the AS into smaller sub-ASs. To devices outside your network, the
confederations appear as one AS. Within the confederation sub-AS, the IBGP neighbors are fully meshed and the MED,
NEXT_HOP, and LOCAL_PREF attributes maintain between confederations.
1. Enter the confederation ID AS number in ROUTER-BGP mode (1 to 65535 for 2–byte, 1 to 4294967295 for 4–byte).
confederation identifier as-number
2. Enter which confederation sub-AS are peers in ROUTER-BGP mode, from 1 to 65535 for 2–byte, 1 to 4294967295 for
4–byte. All Confederation routers must be either 4 bytes or 2 bytes. You cannot have a mix of router ASN support.
confederation peers as-number [... as-number]
Configure BGP confederations
OS10(config)# router bgp 65501
OS10(conf-router-bgp-65501)# confederation identifier 100
OS10(conf-router-bgp-65501)# confederation peers 65502 65503 65504
OS10(conf-router-bgp-65501)# neighbor 1.1.1.2
OS10(conf-router-neighbor)# remote-as 65502
OS10(conf-router-neighbor)# no shutdown
OS10(conf-router-neighbor)# exit
OS10(conf-router-bgp-65501)# neighbor 2.1.1.2
OS10(conf-router-neighbor)# remote-as 65503
OS10(conf-router-neighbor)# no shutdown
Layer 3
303