Configuring Vrfs - Cisco Catalyst 3120 Software Manual

Chapter 38 Configuring IP Unicast Routing
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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
Step 1
configure terminal
Step 2
ip routing
Step 3 ip vrf vrf-name
Step 4
rd route-distinguisher
Step 5
route-target {export | import | both}
route-target-ext-community
Step 6 import map route-map
Step 7 interface interface-id
Step 8
ip vrf forwarding vrf-name
OL-12247-01
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 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.
Purpose
Enter global configuration mode.
Enable IP routing.
Name the VRF, and enter VRF configuration mode.
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)
Create a list of import, export, or import and export route
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.
(Optional) Associate a route map with the VRF.
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.
Associate the VRF with the Layer 3 interface.
Cisco Catalyst Blade Switch 3120 for HP Software Configuration Guide
Configuring Multi-VRF CE
38-69