Configuring Route Leaking With Filtering - Dell S4048T Configuration Manual

Show routing tables of VRFs( after route-export and route-import tags are configured).
Dell# show ip route vrf VRF-Red
O 11.1.1.1/32
C 111.1.1.0/24
O 44.4.4.4/32
C 144.4.4.0/24
Dell# show ip route vrf VRF-Blue
O 22.2.2.2/32
00:00:11
C 122.2.2.0/24
O 44.4.4.4/32
C 144.4.4.0/24
Dell# show ip route vrf VRF-Green
O 33.3.3.3/32
00:00:11
C 133.3.3.0/24
Dell# show ip route vrf VRF-Shared
O 11.1.1.1/32
C 111.1.1.0/24
O 22.2.2.2/32
C 122.2.2.0/24
O 44.4.4.4/32
00:00:11
C 144.4.4.0/24
Important Points to Remember
• If the target VRF conatins the same prefix as either the sourced or Leaked route from some other VRF,
then route Leaking for that particular prefix fails and the following error-log is thrown.
SYSLOG ("Duplicate prefix found %s in the target VRF %d", address,
import_vrf_id) with
• 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 prefixes 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 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
via 111.1.1.1 110/0
Direct, Te 1/11 0/0
via VRF-shared:144.4.4.4 0/0
Direct, VRF-shared:Te 1/4 0/0
via 122.2.2.2
Direct, Te 1/12
via vrf-shared:144.4.4.4 0/0
Direct, vrf-shared:Te 1/4
via 133.3.3.3
Direct, Te 1/13 0/0
via VRF-Red:111.1.1.1 110/0
Direct, VRF-Red:Te 1/11 0/0
via VRF-Blue:122.2.2.2
Direct, VRF-Blue:Te 1/22 0/0
via 144.4.4.4
Direct, Te 1/4
The type/level is EVT_LOGWARNING.
00:00:10
22:39:59
00:32:36
00:32:36
110/0
0/0 22:39:61
00:32:36
0/0 00:32:36
110/0
22:39:61
00:00:10
22:39:59
110/0 00:00:11
22:39:61
110/0
0/0 00:32:36
Virtual Routing and Forwarding (VRF) 1205