Cisco Systems 3750E manual Configuring Aggregate Addresses, 38-60

Chapter 38 Configuring IP Unicast Routing

Configuring BGP

	Command	Purpose
Step 23
	neighbor {ip-address peer-group-name}	(Optional) Configure the software to start storing received
	soft-reconfiguration inbound	updates.
Step 24
	end	Return to privileged EXEC mode.
Step 25
	show ip bgp neighbors	Verify the configuration.
Step 26
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To disable an existing BGP neighbor or neighbor peer group, use the neighbor shutdown router configuration command. To enable a previously existing neighbor or neighbor peer group that had been disabled, use the no neighbor shutdown router configuration command.

Configuring Aggregate Addresses

Classless interdomain routing (CIDR) enables you to create aggregate routes (or supernets) to minimize the size of routing tables. You can configure aggregate routes in BGP either by redistributing an aggregate route into BGP or by creating an aggregate entry in the BGP routing table. An aggregate address is added to the BGP table when there is at least one more specific entry in the BGP table.

Beginning in privileged EXEC mode, use these commands to create an aggregate address in the routing table:

	Command		Purpose
Step 1	configure terminal		Enter global configuration mode.
Step 2	router bgp autonomous-system		Enter BGP router configuration mode.
Step 3	aggregate-address address mask		Create an aggregate entry in the BGP routing table. The aggregate
			route is advertised as coming from the AS, and the atomic aggregate
			attribute is set to indicate that information might be missing.
Step 4	aggregate-address address mask as-set		(Optional) Generate AS set path information. This command
			creates an aggregate entry following the same rules as the previous
			command, but the advertised path will be an AS_SET consisting of
			all elements contained in all paths. Do not use this keyword when
			aggregating many paths because this route must be continually
			withdrawn and updated.
Step 5	aggregate-address address-mask		(Optional) Advertise summary addresses only.
	summary-only
Step 6	aggregate-address address mask		(Optional) Suppress selected, more specific routes.
	suppress-map map-name
Step 7	aggregate-address address mask		(Optional) Generate an aggregate based on conditions specified by
	advertise-map map-name		the route map.
Step 8	aggregate-address address mask		(Optional) Generate an aggregate with attributes specified in the
	attribute-map map-name		route map.
Step 9	end		Return to privileged EXEC mode.
Step 10	show ip bgp neighbors [advertised-routes]		Verify the configuration.
Step 11	copy running-config startup-config		(Optional) Save your entries in the configuration file.
		Catalyst 3750-E and 3560-E Switch Software Configuration Guide
38-60			OL-9775-02