White Papers

To view a route reflector configuration, use the show config command in CONFIGURATION ROUTER BGP mode or the
show running-config bgp in EXEC Privilege mode.
Aggregating Routes
Dell Networking OS provides multiple ways to aggregate routes in the BGP routing table. At least one specific route of the
aggregate must be in the routing table for the configured 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 prefix to aggregate.
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]
In the show ip bgp command, aggregates contain an ‘a’ in the first column and routes the aggregate suppresses contain an
‘s’ in the first column. Aggregate route indicator examples are shown in bold.
Dell#show ip bgp
BGP table version is 0, local router ID is 10.101.15.13
Status codes: s suppressed, d damped, h history, * valid, > best
Path source: I - internal, a - aggregate, c - confed-external, r - redistributed, n -
network
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 7.0.0.0/29 10.114.8.33 0 0 18508 ?
*> 7.0.0.0/30 10.114.8.33 0 0 18508 ?
*>a 9.0.0.0/8 192.0.0.0 32768 18508 701 {7018 2686 3786} ?
*> 9.2.0.0/16 10.114.8.33 0 18508 701 i
*> 9.141.128.0/24 10.114.8.33 0 18508 701 7018 2686 ?
Dell#
Configuring BGP 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, BGP confederations are recommended only for IBGP peering involving many IBGP peering sessions
per router. Basically, when you configure BGP confederations, you break the AS into smaller sub-AS, and to those 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 are maintained between confederations.
To configure BGP confederations, use the following commands.
● Specifies the confederation ID.
CONFIG-ROUTER-BGP mode
bgp confederation identifier as-number
○ as-number: from 0 to 65535 (2 Byte) or from 1 to 4294967295 (4 Byte).
● Specifies which confederation sub-AS are peers.
CONFIG-ROUTER-BGP mode
bgp confederation peers as-number [... as-number]
○ as-number: from 0 to 65535 (2 Byte) or from 1 to 4294967295 (4 Byte).
All Confederation routers must be either 4 Byte or 2 Byte. You cannot have a mix of router ASN support.
To view the configuration, use the show config command in CONFIGURATION ROUTER BGP mode.
Border Gateway Protocol IPv4 (BGPv4)
193