Users Guide

O 22.2.2.2/32 via 122.2.2.2 110/0
00:00:11
C 122.2.2.0/24 Direct, Te 1/12 0/0 22:39:61
O 44.4.4.4/32 via vrf-shared:144.4.4.4 0/0 00:32:36
C 144.4.4.0/24 Direct, vrf-shared:Te 1/4 0/0 00:32:36
Dell# show ip route vrf VRF-Green
O 33.3.3.3/32 via 133.3.3.3 110/0
00:00:11
C 133.3.3.0/24 Direct, Te 1/13 0/0 22:39:61
Dell# show ip route vrf VRF-Shared
O 11.1.1.1/32 via VRF-Red:111.1.1.1 110/0 00:00:10
C 111.1.1.0/24 Direct, VRF-Red:Te 1/11 0/0 22:39:59
O 22.2.2.2/32 via VRF-Blue:122.2.2.2 110/0 00:00:11
C 122.2.2.0/24 Direct, VRF-Blue:Te 1/22 0/0 22:39:61
O 44.4.4.4/32 via 144.4.4.4 110/0
00:00:11
C 144.4.4.0/24 Direct, Te 1/4 0/0 00:32:36
Important Points to Remember
• If the target VRF conatins the same prex as either the sourced or Leaked route from some other VRF, then route Leaking for
that particular prex fails and the following error-log is thrown.
SYSLOG (“Duplicate prefix found %s in the target VRF %d”, address, import_vrf_id) with
The type/level is EVT_LOGWARNING.
• The source routes always take precedence over leaked routes. The leaked routes are deleted as soon as routes are locally learnt
by the VRF using other means.
• For recovery, you must take appropriate action either by deleting the unwanted prexes or issuing clear command or both.
• In the target VRF, you cannot leak routes that are imported through the route leaking feature.
• The leaked route points to the next-hop of the source routes. You cannot do any modications 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.
Conguring 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 lter the routes that are exported and imported into the route targets
based on certain matching criteria. These match criteria include, prex 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 dene 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 dened in route-map
export_ospfbgp_protocol are exposed to VRF-blue.
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Virtual Routing and Forwarding (VRF)