Concept Guide

you use) to various other VRFs. The destinations or target VRFs then import these IPv4 or IPv6 routes using the ip route-import
tag or the ipv6 route-import tag command respectively.
NOTE: In Dell Networking OS, you can congure at most one route-export per VRF as only one set of routes can be exposed for
leaking. However, you can congure multiple route-import targets because a VRF can accept routes from multiple VRFs.
After the target VRF learns routes that are leaked by the source VRF, the source VRF in turn can leak the export target corresponding to
the destination VRFs that have imported its routes. The source VRF learns the export target corresponding to the destinations VRF using
the
ip route-import tag or ipv6 route-import tag command. This mechanism enables reverse communication between
destination VRF and the source VRF.
If the target VRF contains the same prex (either sourced or Leaked route from some other VRF), then the Leak for that particular prex
will fail and an error-log will be thrown. Manual intervention is required to clear the unneeded prexes. The source route will take priority
over the leaked route and the leaked route is deleted.
Consider a scenario where you have created four VRF tables VRF-red, VRF-blue, VRF-Green, and VRF-shared. The VRF-shared table
belongs to a particular service that should be made available only to VRF-Red and VRF-Blue but not VRF-Green. For this purpose, routes
corresponding VRF-Shared routes are leaked to only VRF-Red and VRF-Blue. And for reply, routes corresponding to VRF-Red and VRF-
Blue are leaked to VRF-Shared.
For leaking the routes from VRF-Shared to VRF-Red and VRF-Blue, you can congure route-export tag on VRF-shared (source VRF, who
is exporting the routes); the same route-export tag value should be congured on VRF-Red and VRF-blue as route-import tag (target VRF,
that is importing the routes). For a reply communication, VRF-red and VRF-blue are congured with two dierent route-export tags, one
for each, and those two values are congured as route-import tags on VRF-shared.
To congure route leaking, perform the following steps:
1 Congure VRF-shared using the following command:ip vrf vrf-sharedip vrf forwarding vrf-sharedip address
x.x.x.x 255.x.x.x
A non-default VRF named VRF-Shared is created and the interface 1/4 is assigned to this VRF.
2 Congure the export target in the source VRF:.ip route-export 1:1
3 Congure VRF-red.ip vrf vrf-red ip vrf forwarding VRF-red ip address x.x.x.x 255.x.x.x
A non-default VRF named VRF-red is created and the interface 1/11 is assigned to this VRF.
4 Congure the import target in VRF-red.ip route-import 1:1
5 Congure the export target in VRF-red.ip route-export 2:2
6 Congure VRF-blue.ip vrf vrf-blue ip vrf forwarding vrf-blue ip address x.x.x.x 255.x.x.x
A non-default VRF named VRF-blue is created and the interface 1/12 is assigned to it.
7 Congure the import target in VRF-blue.ip route-import 1:1
8 Congure the export target in VRF-blue.ip route-export 3:3
9 Congure VRF-green.ip vrf vrf-green ip vrf forwarding VRF-green ip address x.x.x.x 255.x.x.x
A non-default VRF named VRF-green is created and the interface 1/13 is assigned to it.
10 Congure the import target in the source VRF VRF-Shared for reverse communication with VRF-red and VRF-blue.ip vrf vrf-
sharedip route—import 2:2ip route-import 3:3
The show run output for the above conguration is as follows:
ip vrf VRF-Red
ip route-export 2:2
ip route-import 1:1
!
ip vrf VRF-Blue
ip route-export 3:3
ip route-import 1:1
!
ip vrf VRF-Green
!
ip vrf VRF-shared
ip route-export 1:1
1096
Virtual Routing and Forwarding (VRF)