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Configuring Virtual-Router Routing Instances in VPNs

A virtual-router routing instance, like a VRF routing instance, maintains separate routing and forwarding tables for each instance. However, many of the configuration steps required for VRF routing instances are not required for virtual-router routing instances. Specifically, you do not need to configure a route distinguisher, a routing table policy (the vrf-export, vrf-import, and route-distinguisher statements), or MPLS between the service provider routers.

Configure a virtual-router routing instance by including the following statements:

You can include these statements at the following hierarchy levels:

  • [edit routing-instances routing-instance-name]

  • [edit logical-systems logical-system-name routing-instances routing-instance-name]

The following sections explain how to configure a virtual-router routing instance:

Configuring a Routing Protocol Between the Service Provider Routers

The service provider routers need to be able to exchange routing information. You can configure the following protocols for the virtual-router routing instance protocols statement configuration at the [edit routing-instances routing-instance-name] hierarchy level:

  • BGP

  • IS-IS

  • LDP

  • OSPF

  • Protocol Independent Multicast (PIM)

  • RIP

You can also configure static routes.

IBGP route reflection is not supported for virtual-router routing instances.

If you configure LDP under a virtual-router instance, LDP routes are placed by default in the routing instance’s inet.0 and inet.3 routing tables (for example, sample.inet.0 and sample.inet.3). To restrict LDP routes to only the routing instance’s inet.3 table, include the no-forwarding statement:

You can include this statement at the following hierarchy levels:

  • [edit routing-instances routing-instance-name protocols ldp]

  • [edit logical-systems logical-system-name routing-instances routing-instance-name protocols ldp]

When you restrict the LDP routes to only the inet.3 routing table, the corresponding IGP route in the inet.0 routing table can be redistributed and advertised into other routing protocols.

For information about routing tables, see Understanding Junos OS Routing Tables.

Configuring Logical Interfaces Between Participating Routers

You must configure an interface to each customer router participating in the routing instance and to each P router participating in the routing instance. Each virtual-router routing instance requires its own separate logical interfaces to all P routers participating in the instance. To configure interfaces for virtual-router instances, include the interface statement:

You can include this statement at the following hierarchy levels:

  • [edit routing-instances routing-instance-name]

  • [edit logical-systems logical-system-name routing-instances routing-instance-name]

Specify both the physical and logical portions of the interface name, in the following format:

For example, in at-1/2/1.2, at-1/2/1 is the physical portion of the interface name and 2 is the logical portion. If you do not specify the logical portion of the interface name, 0 is set by default.

You must also configure the interfaces at the [edit interfaces] hierarchy level.

One method of providing this logical interface between the provider routers is by configuring tunnels between them. You can configure IP Security (IPsec), generic routing encapsulation (GRE), or IP-IP tunnels between the provider routers, terminating the tunnels at the virtual-router instance.

For information about how to configure tunnels and interfaces, see the Junos OS Services Interfaces Library for Routing Devices.