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Configuring Routing Instances for VPNs on the PE Routers

Both PE routers service VPN-A and VPN-B, so you must configure two routing instances on each router, one for each VPN. For each VPN, you must define the following in the routing instance:

Route distinguisher, which must be unique for each routing instance on the PE router.
It is used to distinguish the addresses in one VPN from those in another VPN.
Instance type of vrf, which creates the VRF table on the PE router.
Interfaces connected to the CE routers.

VRF import and export policies, which must be the same on each PE router that services the same VPN. Unless an import policy contains only a then reject statement, it must include reference to a community. Otherwise, when you try to commit the configuration, the commit fails.

Note: In this example, a private AS number is used for the route distinguisher. This number is used for illustration only. When you are configuring VPNs, you should use an assigned AS number.

Routing between the PE and CE routers, which is required for the PE router to distribute VPN-related routes to and from connected CE routers. You can configure a routing protocol—BGP, OSPF, or Routing Information Protocol (RIP)—or you can configure static routing.

On PE Router A, configure the following routing instance for VPN-A. In this example, Router A uses static routes to distribute routes to and from the two CE routers to which it is connected.



[edit]
routing-instance {


VPN-A-Paris-Munich {
instance-type vrf;
interface so-6/0/0.0;
interface so-6/0/1.0;
route-distinguisher 65535:0;
vrf-import VPN-A-import;
vrf-export VPN-A-export;


routing-options {


static {
route 172.16.0.0/16 next-hop so-0/0/0.0;
route 172.17.0.0/16 next-hop so-6/0/1.0;
}


}


}


}

On PE Router C, configure the following routing instance for VPN-A. In this example, Router C uses BGP to distribute routes to and from the CE router to which it is connected.



[edit]
routing-instance {


VPN-A-Tokyo {
instance-type vrf;
interface ge-1/0/0.0;
route-distinguisher 65535:1;
vrf-import VPN-A-import;
vrf-export VPN-A-export;


protocols {


bgp {


group VPN-A-Site2 {
peer-as 1;
neighbor 10.12.1.2;
}


}


}


}


}

On PE Router A, configure the following routing instance for VPN-B. In this example, Router A uses OSPF to distribute routes to and from the CE router to which it is connected.



[edit]
routing-instance {


VPN-B-Madrid {
instance-type vrf;
interface ge-0/3/0.0;
route-distinguisher 65535:2;
vrf-import VPN-B-import;
vrf-export VPN-B-export;


protocols {


ospf {
export bgp-to-ospf;


area 0.0.0.0 {
interface ge-0/3/0;
}


}


}


}


}

On PE Router C, configure the following routing instance for VPN-B. In this example, Router C uses RIP to distribute routes to and from the CE router to which it is connected.



[edit]
routing-instance {


VPN-B-Osaka {
instance-type vrf;
interface at-1/2/0.0;
route-distinguisher 65535:3;
vrf-import VPN-B-import;
vrf-export VPN-B-export;


protocols {


rip {


group PE-C-to-VPN-B {
export bgp-to-rip;
neighbor at-1/2/0;
}


}


}


}


}

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