This article describes How to configure BGP to add new Autonomous system path and add any number of local Autonomous system

Prerequisites

1. Versa Headend should be deployed and functional
2. Versa FlexVNF is connected to a Router and eBGP is established between them

Topology

Configuration

1. By default, routes (direct, static, etc) are not redistributed into BGP table. For example, 50.1.1.0/24 is connected subnet and it is present in routing table, but never was redistributed into BGP table

2. From the “Appliances” page, click on the router that needs to be configured. router1 will be configured for this illustration.

3. Click on the test , where various configuration can be done such as configuring “redistribution policy”, routing protocol (BGP, OSPF).

4. To inject connected route into BGP table, click on Redistribution Policies tab and then on the + icon to add new redistribution policy.
5. On the Add Redistribution Policy tab, click on the + icon which opens up another window called Add Term.
6. From Add Term window, match and action items can be set. For this example, we will select Direct under Protocol 
7. Then under Action, select Accept which means all connected routes in test vrf will be allowed to be redistributed into BGP table.

8. Once redistribution policy is added, the new redistribution policy name would appear under Redistribute to BGP section which needs to be selected and click OK.

9. After successfully adding redistribution policy into bgp, all connected subnets appear in bgp table and also the pfxSent values changed to 2 from 0 which means two prefixes were advertised to the bgp neighbor.

10. As the prefixes are installed in the bgp table, we can change with BGP attributes.
11. Configure Prefix list to match 50.1.1.0/24. Go to BGP tab on the left pane and click on Instance ID which is 100
12. In BGP Instance window, click on Prefix List tab, Give a name allow-only-50 under Prefix List Name and then click on + icon.
13. Configure Sequence Number to 10 , Action set to permit and IP Address/Mask configured to 50.1.1.0/24.

14. Configure BGP policy. From Edit BGP Instance window, click on Peer/Group Policy and give a name of the policy ,click on + icon .
15. Give a Term Name and define Match and Action items. Select the prefix list (allow-only-50) which was created earlier under NLRI. We are interested in match the prefix matched by prefix-list.
16. Click on OK

18. In the Action tab, Select Accept in Accept/Reject option.
19. Set Local Autonomous system Prepend Count to 3.
20. Specify the Autonomous system number that needs to be appended in Autonomous system Path Prepend.

21. We need to add the bgp policy (bgp-policy1) to the neighbor (192.168.1.1) so that 50.1.1.0/24 is advertised with new Autonomous system set values ,Select bgp-policy1 under Export.

22. Now, you will see that three local Autonomous system number is added and new Autonomous system number is also prepended.