Configure Inter-VRF IPv4 Accept Policies on VRFs

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

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.

Before you begin

  • Enable IS-IS globally.

  • Ensure that a route policy exists.

  • Ensure that the VRFs exist.

  • You must configure a route-map to apply.

Procedure

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

    enable

    configure terminal

    router vrf WORD<1-16>

  2. Optional: If you want 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

    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 command show ip isid-list vrf WORD<1-16> 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
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

Variable definitions

The following table defines parameters for the ip isid-list command.

Variable

Value

WORD<1-32>

Creates a name for your I-SID list.

<0-16777215>

Specifies an I-SID value.

list WORD<1-1024>

Specifies a list of I-SID values. For example, in the format 1,3,5,8-10.

The following table defines parameters for the isis accept command.

Variable

Value

adv-rtr <x.xx.xx>

Specifies a specific advertising BEB in which to apply the IS-IS accept policy to routes for a specific advertising BEB. x.xx.xx specifies an SPBM nickname.

The system uses the default global filter unless a filter for a specific advertising BEB exists, in which case the system applies a more specific filter.

The system requires an explicit filter to redistribute routes from a particular VSN. If the default global filter or the filter for a specific advertising BEB does not exist, the system does not redistribute the routes from the remote VSN.

enable

Enables the IS-IS accept policy.

i-sid <0-16777215>

Configures the I-SID to which the IS-IS accept policy applies.

An I-SID value of 0 represents the global routing table (GRT).

isid-list WORD<1-32>

Configures a list of I-SIDs to which the IS-IS accept policy applies.

An I-SID value of 0 represents the global routing table (GRT).

route-map WORD <1-64>

Specifies a route policy.

You must configure a route policy earlier in a separate procedure.

The following table defines parameters for the isis apply accept command.

Variable

Value

vrf WORD<1-16>

Specifies a specific VRF instance.