Aggregating Routes; Configuring Bgp Confederations - Dell Force10 Z9000 Configuration Manual

With route reflection configured properly, IBGP routers are not fully meshed within a cluster but all receive routing information.
Configure clusters of routers where one router is a concentration router and the others are clients who receive their updates from
the concentration router.
To configure a route reflector, use the following commands.
• Assign an ID to a router reflector cluster.
CONFIG-ROUTER-BGP mode
bgp cluster-id cluster-id
You can have multiple clusters in an AS.
• Configure the local router as a route reflector and the neighbor or peer group identified is the route reflector client.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | peer-group-name} route-reflector-client
When you enable a route reflector, Dell Networking OS automatically enables route reflection to all clients. To disable route reflection
between all clients in this reflector, use the no bgp client-to-client reflection command in CONFIGURATION
ROUTER BGP mode. All clients must be fully meshed before you disable route reflection.
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 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]
Example of Viewing Aggregated Routes
In the show ip bgp command, aggregates contain an 'a' in the first column (shown in bold) and routes suppressed by the
aggregate contain an 's' in the first column.
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
*> 7.0.0.0/29 10.114.8.33
*> 7.0.0.0/30 10.114.8.33
*>a 9.0.0.0/8 192.0.0.0
*> 9.2.0.0/16 10.114.8.33
*> 9.141.128.0/24 10.114.8.33
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,
188
Border Gateway Protocol IPv4 (BGPv4)
Metric LocPrf Weight Path
0 0 18508 ?
0 0 18508 ?
32768 18508 701 {7018 2686 3786} ?
0 18508 701 i
0 18508 701 7018 2686 ?