extended community

[jay_7301]

Hi All,

I'm trying to attach an extended community to a specific subnet learned from a CPE using the below config

however i don't see this community attached

ip prefix-list TEST_BGP_IN permit 192.168.1.0/24

route-map TEST_ROUTE_POLICY permit 5
match ip address prefix-list TEST_BGP_IN
set extcommunity rt 31655:2000 additive

router bgp 1
address-family ipv4 vrf INTERNET
neighbor 10.1.1.1 route-map TEST_ROUTE_POLICY in
end

Any help would be appreciated.

[MHM Cisco World]

Neighbor x.x.x.x send-community both

MHM

[jay_7301]

This command is already in place. I was wondering if an extended community can be set on import or if we should be configuring an export-map?

[MHM Cisco World]

Try clear ip bgp if you add this policy after bgp is established 

MHM

[jay_7301]

This has been done also

[MHM Cisco World]

I run lab 
R3-R2 there is mpls VPNv4
R1 to R2 there is ebgp 
when I add route-map add rt additive with direction IN R2 not add RT 
but when I add route-map with direction out toward R3 it work as we need 

sorry it not work with IN direction 

MHM

[Albertt]

Can you try in following way? It should modify the route once is under vrf

route-map ADD_RT_IN permit 10
match ip address prefix-list TEST_BGP_IN
set extcommunity rt 31655:2000 additive

vrf definition INTERNET
rd 31655:100
route-target import 31655:2000
route-target export 31655:2000
address-family ipv4
import map ADD_RT_IN
exit-address-family

[AshSe]

Hello @jay_7301 

Based on the configuration you provided, it seems like you are trying to attach an extended community (route target) to a specific subnet learned from a CPE. However, the extended community is not being applied as expected. Here are some troubleshooting steps and considerations to help resolve the issue:

---

1. Verify the Prefix is Being Matched

• Ensure that the prefix 192.168.1.0/24 is actually being received from the neighbor 10.1.1.1.
• Use the following command to check the received routes:

  show ip bgp vpnv4 vrf INTERNET neighbors 10.1.1.1 received-routes
  

  or, if you're working with IPv4 unicast:

  show ip bgp neighbors 10.1.1.1 received-routes
  

• Confirm that the prefix 192.168.1.0/24 is present in the output.

---

2. Check the Prefix-List

• Ensure that the prefix-list TEST_BGP_IN is correctly matching the prefix 192.168.1.0/24.
• You can verify this by using the following command:

  show ip prefix-list TEST_BGP_IN
  

• Confirm that the prefix 192.168.1.0/24 is permitted by the prefix-list.

---

3. Verify the Route-Map

• Ensure that the route-map TEST_ROUTE_POLICY is being applied correctly and is matching the prefix.
• You can use the following command to check the route-map:

  show route-map TEST_ROUTE_POLICY
  

• Confirm that the route-map is configured to match the prefix-list and set the extended community.

---

4. Check the Extended Community Configuration

• Ensure that the set extcommunity rt 31655:2000 additive command is correctly configured in the route-map.
• The additive keyword ensures that the new extended community is added to any existing communities, rather than replacing them.

---

5. Verify the Neighbor Configuration

• Ensure that the route-map TEST_ROUTE_POLICY is applied to the correct neighbor in the correct address family.
• Use the following command to verify the neighbor configuration:

  show running-config | section router bgp
  

• Confirm that the route-map is applied to the neighbor 10.1.1.1 under the address-family ipv4 vrf INTERNET.

---

6. Check for BGP Extended Community Support

• Ensure that the device supports extended communities for the specific address family and VRF.
• Some platforms or configurations may require additional commands to enable extended community support.

---

7. Verify the Result

• After making the above checks, verify whether the extended community is being attached to the route.
• Use the following command to check the BGP table for the VRF:

  show ip bgp vpnv4 vrf INTERNET
  

• Look for the prefix 192.168.1.0/24 and check if the extended community 31655:2000is attached.

---

8. Debugging

• If the issue persists, enable debugging to see if the route-map is being applied and if the extended community is being set:

  debug ip bgp updates
  

• Monitor the logs for any errors or misconfigurations.

---

Common Issues to Check:

1. Route-map sequence number: Ensure there are no conflicting entries in the route-map that might override the desired behavior.
2. VRF configuration: Ensure that the VRF INTERNET is correctly configured and the neighbor is part of this VRF.
3. BGP configuration: Ensure that the BGP session is established and the routes are being received.

---

If you still face issues after performing these checks, please provide additional details such as the output of the relevant show commands, and I can assist further!

Hope This Helps!!!

AshSe

Forum Tips: 

1. Insert photos/images inline - don't attach.
2. Always mark helpful and correct answers, it helps others find what they need.
3. For a prompt reply, kindly tag @name. An email will be automatically sent to the member.