04-26-2012 08:59 AM - edited 03-07-2019 06:21 AM
Hi all,
I have this BGP setup
R1 -----------R2 ---------------R3----------------------------R4
R3 and R4 are EBGP neighbours.
R1,R2 and R3 are in same AS and are IBGP neighbours.
As we know that R2 will not advertise the routes learned from R3 to R1
so i have config this on R2
neighbor 100.100.100.100 route-reflector-client
R1 loopback 100.100.100.100
R2 loopback 2.2.2.2
R3 loopback 6.6.6.6
When i config the command on R2 below one
neighbour 100.100.100.100 next hop self
Now i do the sh ip bgp on R1
R1 does not show next hop as 2.2.2.2 it shows next hop as R3 loopback address which is 6.6.6.6
I need to know why next hop self does not change the next hop on R1?
Thanks
Mahesh
Solved! Go to Solution.
04-26-2012 11:01 AM
As far as I understood 100.100.100.100 is R1 ip.
R2 is the RR.
R2
route-map reflector
set ip next-hop 2.2.2.2
if 2.2.2.2 is the ip with whom R1 establish it's adjacency
router bgp 6500
nei 100.100.100.100 route-map reflector out
end
clear ip bgp * soft
Dan
04-26-2012 11:14 AM
It applies all the rules configured on route-map to all prefixes advertise to that neighbor.
In your case , it will change the next-hop of all routes advertised to R1.
Here is a link , for futher reading :
http://wiki.nil.com/BGP_route_reflectors
"The next-hop-self neighbor configuration parameter or (most of the) set options of outbound route-map configured on route-reflector clients are ignored for reflected routes. BGP next-hop can be changed set ip next-hop route map command ( BGP next hop propagation feature introduced in IOS release 12.2)"
Dan
04-26-2012 10:25 AM
Mahesh,
Did you try clearing the peering between R2 and R1? You should be able to do a soft reset.
John
04-26-2012 10:45 AM
Hi Mahesh ,
You cannot change the next-hop of the route with "next-hop self" on a RR to a route-reflector client
If you want to change it you must use a route-map and set ip next-hop
Dan
04-26-2012 10:55 AM
Hi Dan,
Thanks for reply.
You mean that on R2 router i can config this
router bgp 6500
route-map reflector
set ip next-hop 100.100.100.100
Let me know if this is right way?
Thanks
Mahesh
04-26-2012 11:01 AM
As far as I understood 100.100.100.100 is R1 ip.
R2 is the RR.
R2
route-map reflector
set ip next-hop 2.2.2.2
if 2.2.2.2 is the ip with whom R1 establish it's adjacency
router bgp 6500
nei 100.100.100.100 route-map reflector out
end
clear ip bgp * soft
Dan
04-26-2012 11:03 AM
By tthe way when you are setting the next-hop as it's own IP , you will get an warning. Do not worry about it
Dan
04-26-2012 11:08 AM
Hi Dan,
It worked fine now.
So just last thing what does command nei 100.100.100.100 route-map reflector out do?
Thanks
Mahesh
04-26-2012 11:14 AM
It applies all the rules configured on route-map to all prefixes advertise to that neighbor.
In your case , it will change the next-hop of all routes advertised to R1.
Here is a link , for futher reading :
http://wiki.nil.com/BGP_route_reflectors
"The next-hop-self neighbor configuration parameter or (most of the) set options of outbound route-map configured on route-reflector clients are ignored for reflected routes. BGP next-hop can be changed set ip next-hop route map command ( BGP next hop propagation feature introduced in IOS release 12.2)"
Dan
04-26-2012 11:17 AM
Hi Dan,
Many thanks for reply back.
Regards
Mahesh
04-26-2012 11:19 AM
My pleasure , Mahnesh.
Dan
04-26-2012 10:48 AM
Hi John,
yes i clear the routes by clear ip bgp * on both routers.
Thanks
Mahesh
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