To view a route reflector configuration, use the show config command in CONFIGURATION ROUTER BGP mode or the showrunning-config bgp in EXEC Privilege mode.Aggregating RoutesDell Networking OS provides multiple ways to aggregate routes in the BGP routing table. At least one specific route of the aggregate mustbe 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 modeaggregate-address ip-address mask [advertise-map map-name] [as-set] [attribute-map map-name][summary-only] [suppress-map map-name]Example of Viewing Aggregated RoutesIn the show ip bgp command, aggregates contain an ‘a’ in the first column (shown in bold) and routes suppressed by the aggregatecontain an ‘s’ in the first column.Dell#show ip bgpBGP table version is 0, local router ID is 10.101.15.13Status codes: s suppressed, d damped, h history, * valid, > bestPath source: I - internal, a - aggregate, c - confed-external, r - redistributed, n - networkOrigin codes: i - IGP, e - EGP, ? - incompleteNetwork 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 ConfederationsAnother 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, theconfederations appear as one AS. Within the confederation sub-AS, the IBGP neighbors are fully meshed and the MED, NEXT_HOP, andLOCAL_PREF attributes are maintained between confederations.To configure BGP confederations, use the following commands.• Specifies the confederation ID.CONFIG-ROUTER-BGP modebgp 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 modebgp 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.218 Border Gateway Protocol IPv4 (BGPv4)
