Define a BGP4 Extended Community Filter

You must define a BGP4 extended community filter before you can apply the filter.

Procedure

Access global configuration mode.
```
device# configure terminal
```
Specify an extended community list instance.
```
device(config)# ip extcommunity-list 1 permit soo 123:2
```
This example specifies the extended community list and permits site of origin (SOO) from network 2 in autonomous system 123.

Note
The ip-extcommunity-list command supports a range of extended instances from 100 through 500, beyond the standard range of 1 through 99.
Create a route map instance and enter route-map configuration mode.
```
device(config)# route-map extComRmap permit 10
```
This example creates the extComRmap route map that permits (allows) a matching pattern, with an instance ID of 10.
Configure the route map to match the extended community list number.
```
device(config-route-map-extComRmap/permit/10)# match extcommunity 1
```

Exit route-map configuration mode.

device(config-route-map-extComRmap/permit/10)# exit

Define the route map and enter route-map configuration mode.
```
device(config)# route-map sendExtComRmap permit 10
```
Specify the route target (RT) extended community attribute.
```
device(config-route-map-sendExtComRmap/permit/10)# set extcommunity rt 3:3
```
This example specifies the set extcommunity command, the rt keyword, and theextcommunity value variable.
Set the extended community attribute in the route-map instance.
```
device(config-route-map-sendExtComRmap/permit/10)# set extcommunity soo 2:2
```
This example specifies the SOO extended community attribute with the soo keyword and theextcommunity value variable.

Example

The following example summarizes the commands in the procedure.

device# configure terminal
device(config)# ip extcommunity-list 1 permit soo 123:2
device(config)# route-map extComRmap permit 10
device(config-route-map-extComRmap/permit/10)# match extcommunity 1
device(config-route-map-extComRmap/permit/1u)# exit
device(config)# route-map sendExtComRmap permit 10
device(config-route-map-sendExtComRmap/permit/10)# set extcommunity rt 3:3
device(config-route-map-sendExtComRmap/permit/10)# set extcommunity soo 2:2