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eBGP Multihop - Unable to Install Loopback BGP Routes Into RIB (Learned by Static)

Peart
Level 1
Level 1

Hello! Apologies in advance if this question doesn't make sense as I am just starting to learn eBGP Multihop.

My topology is : R14 <---> R13 <----> R6  /// Where R6 and R14 are established and exchanging their loopbacks.

I believe I have the configuration correct, as I am able to establish peering between the two nodes.  However, when I advertise each routers loopback into the neighbor AS, I am always left with "r>". 

After looking at this for a while and running a couple debugs, it looks like this is only happening because I have static routers configured already to reach these loopbacks and they are taking precedent over the BGP routes.

So my question is, is there anyway to install these routes into the RIB at all? I'm confused because the video I was watching on this by Chris Bryant has him running a much similar setup (only difference is frame relay between the nodes) and our configs are the same, yet he is installing these routes into his RIB successfully (" *> ")

Thanks for any clarification on this, I'd like to clear this up a little bit before I go deeper into BGP

1 Accepted Solution

Accepted Solutions

ngkin2010
Level 7
Level 7

Hi,

 

show ip bgp rib-failure 

This command will tell you the reason of rib-failure. And as you have stated, it's very likely you already have a lower AD route (e.g. static route) to that particular prefix learnt via BGP (e.g. the loopback address). 

 

 

First, you should ask, why do you need the static route if your router could learnt the route via BGP?

 

Do you use it (the static route) to form EBGP neighbor and without that static route, you couldn't peering the BGP neighbor? 

 

If there is no special purpose, just simply remove the static route, and that prefix (learnt via BGP) will be installed to routing table.

 

Please post your network topology and configuration for further discussion.

 

View solution in original post

6 Replies 6

Hello,

 

which video are you referring to, can you post the link ?

So, in his Udemy course for CCNP it's: 

 

216. BGP 5: Advertising Routes With The "Network" Command

https://www.udemy.com/course/ccnpallinone/learn/lecture/3850074#overview

 

If you'd like I can post some output from my EVE Lab as well. Thanks for your help

 

Hello,

 

the link you have posted seems to be directed to a paid course, so there is no way to check this here. I don't see a way to get a BGP route or the loopbacks into the RIB, the static route will always be preferred due to specifics (it is a /32 route) and metrics (1).

The best would be if you could post some sort of snapshot of the configs used, and the routing tables...

ngkin2010
Level 7
Level 7

Hi,

 

show ip bgp rib-failure 

This command will tell you the reason of rib-failure. And as you have stated, it's very likely you already have a lower AD route (e.g. static route) to that particular prefix learnt via BGP (e.g. the loopback address). 

 

 

First, you should ask, why do you need the static route if your router could learnt the route via BGP?

 

Do you use it (the static route) to form EBGP neighbor and without that static route, you couldn't peering the BGP neighbor? 

 

If there is no special purpose, just simply remove the static route, and that prefix (learnt via BGP) will be installed to routing table.

 

Please post your network topology and configuration for further discussion.

 

Thanks, this pretty much confirms what I was thinking: if the route to the node is being learned by a static route, not only will the route from BGP not be installed in the RIB but also does not need to.  Not sure what configuration Chris was doing to get his to install, but I suppose it's not a huge deal.

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