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route-map next hop assitance

Hi networkers, 

First, my apologies if this topic has been re-asked, but unfortunately, I have been searching from Cisco documentation as well as other resources and even I did the lab to see the behavior on this, 

 

we have in production some ISR routers with BGP, but Im trying to understand why it is working as it is right now, 

 

Im not a really expert in BGP path manipulation, but just wanted to see if I can get some doubts cleared as to why it is not being used using one command vs the other, 

 

unfortunately, using the virtual lab, it is not the same thing as using real gear right, so attached Im posting a picture on how it looks like 

 

Background: 

R2 is acting as Route Reflector

 

I dont use the route-map FROM-R4 in R3 towards R2 under BGP config, in R3 Im not receiving any networks being advertised by R1

 

I even used the next-hop-self command, but still same behavior, 

 

Not sure if its a IOS issue or a limitation with the Router reflector, BGP, etc cause I have seen the same config in other environments and we have the recommended version as per Cisco on those routers, so not really sure you have experienced something similar with this behavior as such or similar 

 

In my virtual lab environment, as soon as I put the route-map, I get the following message:

 

% Warning: Next hop address is our address

However, in the real network gear, we don't get that message, possibly IOS, model, etc

 

Questions: 

1- Why we have a route-map using the same IP of the router as a next-hop?

 

2- Should it be the same accomplishment by using the next-hop-self command? 

 

3- Any other consideration as is it acting like that ?

 

4- Is it a normal and expected behavior due to the manipulation of the next-hop BGP attribute ? 

 

5- Can someone please explain me? 

 

 

 

2 Replies 2

Georg Pauwen
VIP Master VIP Master
VIP Master

Hello,

 

the message is essentially just a warning. Can you post the full configs of all 4 routers so we can lab test this with different IOS versions ? Which platforms/IOS version are you using in your real environment (where this message does not show up) ?

paul driver
VIP Expert VIP Expert
VIP Expert

Hello


@Kn1ghtR1d3rOfD00m wrote:

Questions: 

1- Why we have a route-map using the same IP of the router as a next-hop? <its not required to policy route in this instance

 

2- Should it be the same accomplishment by using the next-hop-self command? next hop applicable only on R3 facing R2

 

3- Any other consideration as is it acting like that ?

 

4- Is it a normal and expected behavior due to the manipulation of the next-hop BGP attribute ? when you are using RR on R2 as shown should allow advertisment of R1 networks to R3

 


Rrts- 
sh ip bgp
sh ip bgp summary
sh ip protocols
sh ip route


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Kind Regards
Paul
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