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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter38 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 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.
•Line-rate multicast forwarding within a multi-VRF CE is supported.
•A multicast VRF cannot coexist with private VLANs on the same interface.
•A maximum of 1000 multicast routes is supported and can be shared on all VRFs.
•If no VRFs are configured, 105 policies can be configured.
•If even one VRF is configured, 41 policies can be configured.
•If more than 41 policies are configured, VRF cannot be configured.
•VRF and private VLANs are mutually exclusive. You cannot enable VRF on a private VLAN.
Similarly, you cannot enable a private VLAN on a VLAN with VRF configured on the VLAN
interface.
•VRF and policy-based routing (PBR) are mutually exclusive on a switch interface. You cannot
enable VRF when PBR is enabled on an interface. The reverse is also true; you cannot enable PBR
when VRF is enabled on an interface.
•VRF and Web Cache Communication Protocol (WCCP) are mutually exclusive on a switch
interface. You cannot enable VRF when WCCP is enabled on an interface. The reverse is also true;
you cannot enable WCCP when VRF is enabled on an interface.
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, refer to the switch command reference for this release
and the Cisco IOS Switching Services Command Reference, Release 12.2.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 ip routing Enable IP routing.
Step3 ip vrf vrf-name Name the VRF, and enter VRF configuration mode.
Step4 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 an
arbitrary number (A.B.C.D:y)