30.1.6 Extranet [SL-L3A]
- <Structure of this section>
(1) Inter VRF route filtering
Routes between VRFs can be filtered. Routes denied by the filter are not added to the routing table.
(a) How to Apply Filters
The routes between VRFs are filtered by using ipv6 import inter-vrf.
The routes permitted by this filtering are added to the routing table. If there are no applicable filters or every filter gives a deny result, the route is not added.
The table below shows the configuration command used to filter the route between VRFs.
|
Command name |
Filtered routes |
|---|---|
|
ipv6 import inter-vrf |
Routes from a VRF specified as route-map are filtered. |
(b) Route attributes that can be changed by VRF route filtering
The following table describes the changeable attributes of routes that have been imported from another VRF or the global network.
|
Attribute |
Default |
|---|---|
|
Distance |
210 |
|
Tag value |
Inherits the value of the route in the routing table. |
|
AS_PATH attribute |
(c) Configuring Routes Between VRF
Apply an inter-VRF route filter. Routes imported from another VRF or the global network are added to the local VRF routing table according to the filter conditions. For an imported route, the VRF ID in the source routing table is also used in the destination routing table. Note that the protocol type of imported routes becomes extra-vrf.
If the match vrf configuration command is specified in the inter-VRF route filter, the VRF ID is compared against the source routing table. If you do not specify the match vrf command, the same filter conditions are applied to all other VRFs and global networks.
(d) Protocol-based advertisement of VRF routes
If an advertised route filter is specified for a protocol, routes are advertised from the routing table of the VRF where the protocol is running. To use routes imported from another VRF or the global network, specify extra-vrf as the protocol in the redistribute configuration command.