1-17

Cisco IP Solution Center, 3.0: MPLS VPN Management User Guide, 3.0
OL-4344-01
Chapter1 About Cisco IP Solution Center
About MPLS VPNs
Figure 1-9 VRFs for Sites in Multiple VPNs
VRF Implementation Considerations

When implementing VPNs and VRFs, Cisco recommends you keep the following considerations in

mind:

•A local VRF interface on a PE is not considered a directly-connected inter face in a traditional sense.

When you configure, for example, a Fast Ethernet interface on a PE to participate in a particular

VRF/VPN, the interface no longer shows up as a directly-connected interface when you issue a show

ip route command. To see that interface in a routing table, you must issue a show ip route

vrf vrf_name command.

•The global routing table and the per-VRF routing table are independent entities. Cisco IOS

commands apply to IP routing in a global routing table context. For example, show ip route, and

other EXEC-level show commands—as well as utilities such as ping, traceroute, and telnet—all

invoke the services of the Cisco IOS routines that deal with the global IP routing table.

•You can issue a standard Telnet command from a CE router to connect to a PE router. However, from

that PE, you must issue the following command to connect from the PE to the CE:

telnet CE_RouterName /vrf vrf_name

Similarly, you can utilize the Traceroute and Ping commands in a VRF context.

28558
Multihop MP-iBGP
PP
PE2PE1
ip vrf site1
rd 100:1
route-target export 100:1
route-target import 100:1
ip vrf site2
rd 100:2
route-target export 100:2
route-target import 100:2
route-target import 100:1
route-target export 100:1
ip vrf site3
rd 100:3
route-target export 100:2
route-target import 100:2
route-target import 100:3
route-target export 100:3
ip vrf site4
rd 100:4
route-target export 100:3
route-target import 100:3
Site 1
Site 1 Site 2 Site 3
VPN A Site 2
Site 4
VPN C
VPN B Site 3
VRF
for site 1
(100:1)
Site 1 routes
Site 2 routes
VRF
for site 2
(100:2)
Site 1 routes
Site 2 routes
Site 3 routes
Site 4
VRF
for site 4
(100:4)
Site 3 routes
Site 4 routes
VRF
for site 3
(100:3)
Site 2 routes
Site 3 routes
Site 4 routes