Configuring Route Leaking With Filtering - Dell Z9500 Configuration Manual

• The leaked route points to the next-hop of the source routes. You cannot do any modifications to the next-hop of the
leaked route in the destination VRF.
• IPv6 link local routes will never be leaked from one VRF to another.

Configuring Route Leaking with Filtering

When you initalize route leaking from one VRF to another, all the routes are exposed to the target VRF. If the size of the source
VRF's RTM is considerablly large, an import operation results in the duplication of the target VRF's RTM with the source RTM
entries. To mitigate this issue, you can use route-maps to filter the routes that are exported and imported into the route targets
based on certain matching criteria. These match criteria include, prefix matches and portocol matches.
You can use the match source-protocol or match ip-address commands to specify matching criteria for importing or
exporting routes between VRFs.
NOTE: You must use the match source-protocol or match ip-address commands in conjunction with the route-map
command to be able to define the match criteria for route leaking.
Consider a scenario where you have created two VRF tables VRF-red and VRF-blue. VRF-red exports routes with the
export_ospfbgp_protocol route-map to VRF-blue. VRF-blue imports these routes into its RTM.
For leaking these routes from VRF-red to VRF-blue, you can use the ip route-export route-map command on VRF-red (source
VRF, that is exporting the routes); you must also specify a match criteria for these routes using the match source-protocol
command. When you leak these routes into VRF-blue, only the routes (OSPF and BGP) that satisfy the matching criteria defined
in route-map export_ospfbgp_protocol are exposed to VRF-blue.
While importing these routes into VRF-blue, you can further specify match conditions at the import end to define the filtering
criteria based on which the routes are imported into VRF-blue. You can define a route-map import_ospf_protocol and then
specify the match criteria as OSPF using the match source-protocol ospf command.
You can then use the ip route-import route-map command to import routes matching the filtering criteria defined in the
import_ospf_protocol route-map. For a reply communication, VRF-blue is configured with a route-export tag. This value is
then configured as route-import tag on the VRF-Red.
To configure route leaking using filtering criteria, perform the following steps:
1 Configure VRF-red:
ip vrf vrf-red
interface-type slot/port
ip vrf forwarding VRF-red
ip address ip—address mask
A non-default VRF named VRF-red is created and the interface is assigned to this VRF.
2 Define a route-map export_ospfbgp_protocol.
Dell(config)route-map export_ospfbgp_protocol permit 10
3 Define the matching criteria for the exported routes.
Dell(config-route-map)match source-protocol ospf
Dell(config-route-map)match source-protocol bgp
This action specifies that the route-map contains OSPF and BGP as the matching criteria for exporting routes from vrf-red.
4 Configure the export target in the source VRF with route-map export_ospfbgp_protocol.
ip route-export 1:1 export_ospfbgp_protocol
5 Configure VRF-blue.
ip vrf vrf-blue
Virtual Routing and Forwarding (VRF) 868