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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

ruter 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

ruter BGP 200
nei 155.1.23.2 remote-as 100
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 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.

Please help to find the resaon behind this.

I'm not sure I totally understand what you're asking here, but if you change the direction of your route-map on both routers, it's possible to change the local next-hop as updates are sent out to the neighbor. 

ruter BGP 200
nei 155.1.146.6 remote-as 100
nei 155.1.146.6 route-map to-R4 out
net 150.1.2.2 mask 255.255.255.255 <----Advt loopback in BGP

route-map to-R4 
set ip next hop 10.10.10.1

Int tu 0

Ip address 10.10.10.1/24

tunnel src 155.1.23.2
tunnel dest 155.1.146.6

Can you also provide the full drawing of your topology? Your BGP connections look strange, R2 and R4 are on ASN 200, but they are peering with router in ASN 100...

A topology diagram could clarify what's going on..

Thanks

R2(F0/0 155.1.23.2)-------------------------CORE------------------------R4(F0/0 155.1.146.4)

R2(F0/0 155.1.23.2)-------------------CORE------------------R4(F0/0 155.1.146.4)

EBGP in between R2 and R4.

Its typo mistakes in ASN number.following is the configuration

On R2

Int tu 0
Ip address 10.10.10.1/24
tunnel src 155.1.23.2
tunnel dest 155.1.146.6

ruter BGP 200
nei 155.1.146.6 remote-as 100
nei 155.1.146.6 route-map fromR2 in
net 150.1.2.2 mask 255.255.255.255 <----Advt loopback in BGP

route-map fromR2
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

ruter BGP 100
nei 155.1.23.2 remote-as 100
nei 155.1.23.2 route-map fromR6 in
net 150.1.6.6 mask 255.255.255.255 <----Advt loopback in BGP

route-map fromR6

set ip next hop 10.10.10.1

If you try to change the next hop ip addresses like you are trying to, it will not work. Think like this if i need to reach 150.1.6.6 from R2 and next hop is 10.10.10.1 that means to reach that destination use next hop ip address of myself (tunnel int) instead of R6, so it will just loop back to it self and pings will fail because i dont have 150.1.6.6. try this same problem but just for testing create another Loopback on R2 with same ip address 150.1.6.6 and see it should then ping but in reality it will be successful because you have a loopback locally. same thing for R6. So either change the direction of route-map if you want to use the latter next hop ip addresses or try to use next-hop-self command and see what happens. i hope this helps.

topology attached

Attachment cannot be seen, could you reup it?

I actually dont get why you have the inbound route-map.

On R2 you have a inbound route-map that says "everything that you get from this neighbor, send it to 10.10.10.2.".

But 10.10.10.2 is at R6 (the machine where the update came from and from whom you know the network!?).

Is that right?

Regards!

Markus.

Markus,

If the next hop is not changed to tunnel's IP address in this case traffic will get droped becuase the transit routers are not running BGP so there are 2 ways to resolve that, either redistribute BGP into IGP or create a tunnel over you IGP and form neighborship over that. since in his case he has tunnel but neighborship is not being formed using tunnel IPs it has to be changed through route-maps. If neighborship was using tunnel IPs we could next-hop-self for iBGP neighborship.

Tahir

Hi Markus,

Folloing is the simplified configuration (with Route-map name)

On R2

Int tu 0
Ip address 10.10.10.1/24
tunnel src 155.1.23.2
tunnel dest 155.1.146.6

ruter BGP 200
nei 155.1.146.6 remote-as 100
nei 155.1.146.6 route-map fromR6 in
net 150.1.2.2 mask 255.255.255.255 <----Advt loopback in BGP

route-map fromR6
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

ruter BGP 100
nei 155.1.23.2 remote-as 200
nei 155.1.23.2 route-map fromR2 in
net 150.1.6.6 mask 255.255.255.255 <----Advt loopback in BGP

route-map fromR2

set ip next hop 10.10.10.1

------------------------------------------------------------

What u r saying is correct.

My confusion is it i set nextHOP as 10.10.10.1 on R2 from route that are getting from R6 its not working.

As per my understanding by setting the nextHOP as 10.10.10.1 i am forcing the traffic to use tunnel 0 to to rech network behind R6 ie.118.0.0.0/30

As per my understanding by setting the nextHOP as 10.10.10.1 i am forcing the traffic to use tunnel 0 to to rech network behind R6 ie.118.0.0.0/30

no your understanding is not correct in this case, if you set next hop 10.10.10.1 on R2 it will not work, by setting next hop to your own interface facing the neighbor does not not make is reachable, its not like setting the outgoing interface. when setting next hop ip address its always the ip address of your neighbor, just like static routes.

ooh..Thanks for the great explanation.

I will try to set out going  interfcace as tunnel interface  instead of next Hop IP address and let  you know.

Thanks

Ganpat