jncip-EBGP case study Q

gemesat

Dears ,

in the Ebgp case study :


>>Prepend 64512 64512 to all routes received from P1. Ensure that transit providers do not receive these AS numbers.


for that we add command remove-private to the bgp session between R3&T1&T2
BUT in this case the routes which advertised by C1&C2 will be appeared to T1&T2 without thier AS-path because the command(remove private) will remove 65020& 65010 from thier AS-path

root@r6> show route advertising-protocol bgp 172.16.0.22

inet.0: 42 destinations, 47 routes (42 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
10.0.0.0/8 Self 1 I
* 120.120.0.0/16 Self 2 1492 I
* 130.130.0.0/16 Self 2 I
172.16.40.0/28 Self 1 I
192.168.0.0/22 Self 1 I
* 200.200.0.0/16 Self 2 I
* 201.201.0.0/16 Self 1 I



but without (remove-private command )

---

root@r6> show route advertising-protocol bgp 172.16.0.22

inet.0: 42 destinations, 47 routes (42 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
10.0.0.0/8 Self 1 I
* 120.120.0.0/16 Self 2 64512 64512 1492 I
172.16.40.0/28 Self 1 I
192.168.0.0/22 Self 1 I
* 200.200.0.0/16 Self 2 65010 I
* 201.201.0.0/16 Self 1 65413 65020 I




The Question : can i get another solution to remove the private AS from certain neighbor (P1) without any effect on the other neighbors (C1&C2) ???



i m looking forward to your reply ,,, Share meee


Thx
Geme,

darry9502

The purpose of the remove-private-as is to remove the private AS so that the other BGP peering see only public AS numbers.

If you are looking at BGP options to do this, I dont think there are any other commands which will mask off the private-as-number.

Another one way is to make use of IGP to advertise the learnt routes from P1 and originating them from its own AS. See below,

1) Deny the P1 BGP routes from being advertised to the other IBGP nei. However, redistributed those P1 BGP routes into your IGP.

2) At the other end where you need to advertise the P1 routes, redistributed it from your IGP and advertised it as your own routes.