02-11-2012 06:00 AM - edited 03-04-2019 03:13 PM
====================================================================
R2 ------------------CORE----------------------R6
f0/0 f0/0
155.1.23.2 155.1.146.6
====================================================
R2 is advertising 222.22.2.0/30 in BGP and R6 is advt 118.0.0.0/30 in BGP.
No BGP in the core and no redistributaion is allowed from BGP to IGP in core.
Requriment :- R2 should ping to 118.0.0.0/30 with source as LOOPBACK IP
and R6 should ping to 222.22.2.0/30 with source as LOOPBACK IP
-----
On R2
-----
Int tu 0
Ip address 10.10.10.1/24
tunnel src 155.1.23.2
tunnel dest 155.1.146.6
router BGP 200
nei 155.1.146.6 remote-as 100
nei 155.1.146.6 route-map fromR4 in
net 150.1.2.2 mask 255.255.255.255 <----Advt loopback in BGP
route-map fromR4
set ip next hop 10.10.10.2
-------
On R6
-------
Int tu 0
Ip address 10.10.10.2/24
tunnel src 155.1.146.6
tunnel dest 155.1.23.2
router BGP 100
nei 155.1.23.2 remote-as 200
nei 155.1.23.2 route-map fromR4 in
net 150.1.6.6 mask 255.255.255.255 <----Advt loopback in BGP
route-map fromR4
set ip next hop 10.10.10.1
I have done the above mentioned configuration(With BGP multihop) and everthing is working fine(Tunnel are UP)
However if i change the nexthop on R2 to 10.10.10.1 and on R6 to 10.10.10.2 its not working.
As per my understanding its should work as by setting up the next hop to 10.10.10.1 i am forcing traffic via tunnel.
Please help to find the resaon behind this.
02-11-2012 07:49 AM
Hi,
Do you have a static route on r2 to reach 10.10.10.2 and on r6 to reach 10.10.10.1?
Can you reach 10.10.10.1 and 10.10.10.2 from the each router?
HTH
02-11-2012 11:27 AM
Hi Ganpat,
as your Tunnel interfaces will remain up no matter BGP is working or not, why don't you change the BGP neighbor as the tunnel interface ip of the peer i.e for R2:
router BGP 200
nei 10.10.10.2 remote-as 100
And for R6:
router BGP 100
nei 10.10.10.1 remote-as 200
This might accomplish what you are looking for and you wouldn't have to change the next-hop using that route-map either
HTH
Neeraj
02-12-2012 07:29 AM
Hi Neeraj,
Configuring BGP on tunnel is the one option.However in the task that option is not permitted so i have to use next hop change option.
What i am looking is ....If i set ip next hop 10.10.10.2 on R2,then R2 is sending the traffic via tunnel.
Then why R2 is not forwording the traffic by tunnel if i set ip next hop 10.10.10.1. ?
/Ganpat
09-06-2013 07:50 PM
This issue might no longer exist, but for the sake of others who might have the same questio;,
The config seems fine. It is possible that the BGP session between R2 and R6 needs to be cleared in order to reflect the new next-hop information.
The command to do so is #clear ip BGP
Verify that the next-hop shows up in the BGP table as the tunnel interface addresses and you should be good to go.
Cheers
#saxotob
09-06-2013 08:36 PM
It wasn't specifcally mentioned, but since it's an eBGP connection, you'd need "ebgp-multihop" to establish the session.
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