Dell S3048-ON - Aggregating Routes; Configuring BGP Confederations

To view a route reector conguration, 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 specic route of the aggregate must
be in the routing table for the congured 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 prex 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 rst column (shown in bold) and routes suppressed by the aggregate
contain an ‘s’ in the rst 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 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#
Conguring BGP Confederations
Another way to organize routers within an AS and reduce the mesh for IBGP peers is to congure BGP confederations.
As with route reectors, BGP confederations are recommended only for IBGP peering involving many IBGP peering sessions per router.
Basically, when you congure 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 congure BGP confederations, use the following commands.
• Species 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).
• Species 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.
Border Gateway Protocol IPv4 (BGPv4)
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