Reference Guide

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The following shows the output of the show commands on Router 2.
Router 2
Route Leaking VRFs
Static routes can be used to redistribute routes between non-default to default/non-default VRF and
vice-versa.
You can configure route leaking between two VRFs using the following command: ip route vrf
x.x.x.x s.s.s.s nh.nh.nh.nh vrf default.
This command indicates that packets that are destined to x.x.x.x/s.s.s.s are reachable through
nh.nh.nh.nh in the default VRF table. Meaning, the routes to x.x.x.x/s.s.s.s are leaked from the
default VRF routing table into the non-default VRF routing table.
The following example illustrates how route leaking between two VRFs can be performed:
interface TenGigabitEthernet 1/9/1
ip vrf forwarding VRF1
ip address 120.0.0.1/24
interface TenGigabitEthernet 1/10/1
ip vrf forwarding VRF2
ip address 140.0.0.1/24
ip route vrf VRF1 20.0.0.0/16 140.0.0.2 vrf VRF2
ip route vrf VRF2 40.0.0.0/16 120.0.0.2 vrf VRF1
Dynamic Route Leaking
Route Leaking is a powerful feature that enables communication between isolated (virtual) routing
domains by segregating and sharing a set of services such as VOIP, Video, and so on that are available on
one routing domain with other virtual domains. Inter-VRF Route Leaking enables a VRF to leak or export
routes that are present in its RTM to one or more VRFs.
Dynamic Route Leaking enables a source VRF to share both its connected routes as well as dynamically
learnt routes from various protocols, such as ISIS, OSPF, BGP, and so on, with other default or non-
default VRFs.
You can also leak global routes to be made available to VRFs. As the global RTM usually contains a large
pool of routes, when the destination VRF imports global routes, these routes will be duplicated into the
VRF's RTM. As a result, it is mandatory to use route-maps to filter out leaked routes while sharing global
routes with VRFs.
Configuring Route Leaking without Filtering Criteria
You can use the ip route-export tag command to export all the IPv4 routes corresponding to a
source VRF. For leaking IPv6 routes, use the
ipv6 route-export tag command. This action exposes
source VRF's routes (IPv4 or IPv6 depending on the command that you use) to various other VRFs. The
Virtual Routing and Forwarding (VRF)
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