Vrf And Mpls - HP 7102dl - ProCurve Secure Router Configuration Manual

VRF and MPLS

An ISP uses Virtual Routing and Forwarding (VRF) to separate one customer's
routes from another's and Multiprotocol Label Switching (MPLS) to ensure
that the routes reach only the authorized remote sites. Without VRF, customers
could not transmit private network routes between remote sites: the ISP
routers would have no way of knowing which route belonged to which
customer.
For example, in Figure 15-15 an ISP router connects to Customer A and
Customer B, both of whom use the network address 10.1.1.0 /24. The ISP
router must be able to associate one 10.1.1.0 /24 with the public address for
Customer A and the other with Customer B.
On the ISP edge router, routes are first separated by the physical or logical
interface on which they arrive. The router then stores routes from each
customer in a separate VFR routing table. Different customers' routing tables
cannot mix.
Customer A
Network
10.1.1.0 /24
Figure 15-15. VFR
IP Routing—Configuring RIP, OSPF, BGP, and PBR
Routing table A
10.1.1.0 /24 1.1.1.2
Router A
1.1.1.2/30
Customer B
Configuring BGP
Routing table B
10.1.1.0 /24 2.2.2.2
ISP
2.2.2.2
Router B
Network
10.1.1.0 /24
15-69