Cisco Systems 3750E manual 38-53

Chapter 38 Configuring IP Unicast Routing

Configuring BGP

Beginning in privileged EXEC mode, follow these steps to configure some decision attributes:

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	router bgp autonomous-system	Enable a BGP routing process, assign it an AS number,
		and enter router configuration mode.
Step 3
	bgp best-path as-path ignore	(Optional) Configure the router to ignore AS path length
		in selecting a route.
Step 4
	neighbor {ip-address peer-group-name}next-hop-self	(Optional) Disable next-hop processing on BGP updates
		to a neighbor by entering a specific IP address to be used
		instead of the next-hop address.
Step 5
	neighbor {ip-address peer-group-name}weight	(Optional) Assign a weight to a neighbor connection.
	weight	Acceptable values are from 0 to 65535; the largest weight
		is the preferred route. Routes learned through another
		BGP peer have a default weight of 0; routes sourced by the
		local router have a default weight of 32768.
Step 6
	default-metric number	(Optional) Set a MED metric to set preferred paths to
		external neighbors. All routes without a MED will also be
		set to this value. The range is 1 to 4294967295. The lowest
		value is the most desirable.
Step 7
	bgp bestpath med missing-as-worst	(Optional) Configure the switch to consider a missing
		MED as having a value of infinity, making the path
		without a MED value the least desirable path.
Step 8
	bgp always-compare med	(Optional) Configure the switch to compare MEDs for
		paths from neighbors in different autonomous systems. By
		default, MED comparison is only done among paths in the
		same AS.
Step 9
	bgp bestpath med confed	(Optional) Configure the switch to consider the MED in
		choosing a path from among those advertised by different
		subautonomous systems within a confederation.
Step 10
	bgp deterministic med	(Optional) Configure the switch to consider the MED
		variable when choosing among routes advertised by
		different peers in the same AS.
Step 11
	bgp default local-preference value	(Optional) Change the default local preference value. The
		range is 0 to 4294967295; the default value is 100. The
		highest local preference value is preferred.
Step 12
	maximum-paths number	(Optional) Configure the number of paths to be added to
		the IP routing table. The default is to only enter the best
		path in the routing table. The range is from 1 to 16. Having
		multiple paths allows load-balancing among the paths.
		(Although the switch software allows a maximum of
		32 equal-cost routes, the switch hardware will never use
		more than 16 paths per route.)
Step 13
	end	Return to privileged EXEC mode.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		38-53