17.1.3 IPv4 multicast extranet
- <Structure of this section>
(1) Inter VRF route filtering
Routes between VRFs can be filtered. Routes that are not introduced as a result of filtering do not generate IPv4 multicast routing information.
(a) How to Apply Filters
Set to the upstream VRF. Filters the allowed group addresses for route advertisements from the forwarding destination VRF according to the settings of the configuration command import multicast inter-vrf. If the filtered route is permit, the route is imported into IPv4 multicast route. If there is no filter to be applied, no route is introduced.
The following tables show the configuration commands used to filter routes between IPv4 multicast VRF.
|
Command name |
Filtered routes |
|---|---|
|
import multicast inter-vrf |
The forwarding request from VRF specified in route-map is filtered. |
The following tables show the filtering criteria for route-map in IPv4 multicast extranets. Any other conditions are ignored.
|
Route attribute used as conditions |
Description |
Configuration commands |
|---|---|---|
|
Destination IPv4 multicast group address |
Filters IPv4 multicast group address of the destination by specifying access-list identifier as the criteria. A match is assumed if the filter action is permit. If this condition is not set, all IPv4 multicast group addresses are permitted. |
match ip address ip access-list standard |
|
VRF ID |
Specifies a VRF ID as the criteria and compares it with VRF ID of the route. This allows forwarding requests from the specified VRF. If the same ID as VRF for which this command is set is specified, that ID is ignored. This allows you to group several VRF together to use a common route-map. If this parameter is not set, forwarding requests from all VRF are permitted. |
match vrf |
(b) Configuring Routes Between VRF
Apply an inter-VRF route filter. Based on the filtering criteria, routes requested for forwarding from another VRF or global network are introduced into IPv4 multicast routing information of the local VRF. The imported routes are added to the forwarding destination interfaces of the introduction destination IPv4 multicast routing information. When match vrf of the configuration command is specified for the route filter between IPv4 multicast VRF, it is compared with VRF ID of the forwarding requestor. If you do not specify the match vrf command, the same filter conditions are applied to all other VRFs and global networks.
(c) Protocol-based advertisement of VRF routes
You can configure route filtering on VRF to allow forwarding requests from other VRF or globalnetworks. When a forwarding request is received from another VRF or a global network and the result of filtering is permitted, IPv4 multicast routing information is generated, and if there is an upstream router, the forwarding request is sent to the upstream router.
In order for another VRF or global network to send a forwarding request to the local VRF, a route to the source IP is set as the local VRF in the unicast extranet for VRF that is the source of the forwarding request.