Configure Inter-VRF IPv4 Accept Policies on VRFs

About this task

Configure IS-IS accept policies on a VRF to use inter-VRF accept policies in the SPB cloud. You can use IS-IS accept policies to redistribute routes between different VRFs, including the global routing table (GRT). First you apply the filter, and then you match the filter based on the I-SID, which represents the Layer 3 VSN context.

Note

• The isis apply accept [vrf WORD<1-16>] command can disrupt traffic and cause temporary traffic loss. After you apply isis apply accept [vrf<1-16>], the command reapplies the accept policies, which deletes all of the IS-IS route,s and adds the IS-IS routes again. You should make all the relevant accept policy changes, and then apply isis apply accept [vrf WORD<1-16>] at the end.

• If you use the accept command for inter-VRF routes based on the remote I-SID, the device only accepts routes coming from remote BEBs. For instance, if a local Layer 3 VSN exists with the same I-SID, the device does not add the local routes. The assumption is that the device uses existent methods, either through use of another protocol or static configuration, to obtain those routes.

• If the route policy changes, you must reapply the IS-IS accept policy, unless it was the last sequence in the configuration.

1. Enter VRF Router Configuration mode for a specific VRF context:

   enable

   configure terminal

   router vrf WORD<1-16>

2. Optional: To accept routes from a variety of I-SIDs, create an I-SID list before you create an IS-IS accept policy for the I-SID list:

   ip isid-list WORD<1–32> [<0–16777215>][list WORD<1–1024>]

   

   Note

   When creating an I-SID list, you can add I-SID entries until the maximum limit for supported Layer 3 I-SIDs is reached. The system truncates any additional I-SID entries. The maximum limit includes the I-SIDs for locally configured Layer 3 VSNs and the I-SIDs specified for IS-IS accept policy filters.

   Use the show ip isid-list vrf WORD<1-16> command to view the list of truncated I-SIDs.

3. Create an IS-IS accept policy instance to apply to routes from all Backbone Edge Bridges (BEBs):

   isis accept [i-sid <0-16777215>][isid-list WORD<1-32>]

4. Create an IS-IS accept policy instance to apply to routes for a specific BEB:

   isis accept [adv-rtr <x.xx.xx>][i-sid <0-16777215>][isid-list WORD<1-32>]

5. Specify an IS-IS route policy to apply to routes from all BEBs:

   isis accept route-map WORD<1–64>

6. Specify an IS-IS route policy to apply for a specific BEB:

   isis accept adv-rtr <x.xx.xx> route-map WORD<1–64>

7. Enable a configured IS-IS accept policy instance:

   isis accept [adv-rtr <x.xx.xx>][i-sid <0-16777215>][isid-list WORD<1-32>] [enable]

8. Exit VRF Router Configuration mode:

   exit

   You are in Global Configuration mode.

9. Apply the IS-IS accept policy changes, which removes and re-adds all routes with updated filters:

   isis apply accept [vrf WORD<1–16>]

Example

Configure Inter-VRF accept policies on a VRF:

Switch:1>enable
Switch:1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Switch:1(config)#router vrf green
Switch:1(router-vrf)#isis accept i-sid 100
Switch:1(router-vrf)#isis accept i-sid 100 enable
Switch:1(router-vrf)#exit
Switch:1(config)#isis apply accept vrf green