Cisco Systems 3750E manual Configuring VRFs, Route-target export import both, Import map route-map

Chapter 38 Configuring IP Unicast Routing

Configuring Multi-VRF CE

•A customer can use multiple VLANs as long as they do not overlap with those of other customers. A customer’s VLANs are mapped to a specific routing table ID that is used to identify the appropriate routing tables stored on the switch.

•A Catalyst 3750-E or 3560-E switch supports one global network and up to 26 VRFs.

•Most routing protocols (BGP, OSPF, RIP, and static routing) can be used between the CE and the PE. However, we recommend using external BGP (EBGP) for these reasons:

–BGP does not require multiple algorithms to communicate with multiple CEs.

–BGP is designed for passing routing information between systems run by different administrations.

–BGP makes it easy to pass attributes of the routes to the CE.

•Multi-VRF CE does not affect the packet switching rate.

•VPN multicast is not supported.

•You can configure 104 policies whether or not VRFs are configured on the switch or switch stack.

•You can enable VRF on a private VLAN, and the reverse.

•You cannot enable VRF when policy-based routing (PBR) is enabled on an interface, and the reverse.

•You cannot enable VRF when Web Cache Communication Protocol (WCCP) is enabled on an interface, and the reverse.

Configuring VRFs

Beginning in privileged EXEC mode, follow these steps to configure one or more VRFs. For complete syntax and usage information for the commands, see the switch command reference for this release and the Cisco IOS Switching Services Command Reference, Release 12.2.

		Command	Purpose
	Step 1
		configure terminal	Enter global configuration mode.
	Step 2
		ip routing	Enable IP routing.
	Step 3
		ip vrf vrf-name	Name the VRF, and enter VRF configuration mode.
	Step 4
		rd route-distinguisher	Create a VRF table by specifying a route distinguisher.
			Enter either an AS number and an arbitrary number
			(xxx:y) or an IP address and arbitrary number (A.B.C.D:y)
	Step 5 route-target {export import both}		Create a list of import, export, or import and export route
		route-target-ext-community	target communities for the specified VRF. Enter either an
			AS system number and an arbitrary number (xxx:y) or an
			IP address and an arbitrary number (A.B.C.D:y). The
			route-target-ext-community should be the same as the
			route-distinguisher entered in Step 4.
	Step 6
		import map route-map	(Optional) Associate a route map with the VRF.
	Step 7
		interface interface-id	Specify the Layer 3 interface to be associated with the
			VRF, and enter interface configuration mode. The
			interface can be a routed port or SVI.
	Step 8
		ip vrf forwarding vrf-name	Associate the VRF with the Layer 3 interface.
	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
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