BGP understanding

Answered Question
Feb 18th, 2009
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Hi guys,


As I'm trying to understand the basic BGP way of working, I have a questiong that I need someones help to answer:


If I want to use in my AS as IGP, BGP, and I want all the updates to be sent as source from loopback interfaces, before all the BGP will go up, do I have to make static routes for all my speekers to all the loopbacks of all my peers? I mean in order for a router to have a neighbor relation with another one, it has to have the neigh IP in his routing table (from my understanding), as R1 to see R2's loop, do I have to add it before making the neigh statments a static route to this loopback?


Is it not possible to just add the loopback in the router bgp AS configuration as a "network" statment?


To be more precise what I am asking here I will try to give the simplest example that comes into my mind right now:


R1<->R2

R1 -> R2 directly connected with 10.10.10.0/32

R1 - has lo 1.1.1.1

R2 - has lo 2.2.2.2


for R1 I want as a neighbor 2.2.2.2

for R2 -> 1.1.1.1


from R1 to 2.2.2.2 has to be a static route? or I can just add in the network statment under bgp of R2, network 2.2.2.2 and R1 should learn it via BGP?


Thank You

Ivian

Correct Answer by Jon Marshall about 8 years 4 months ago

Ivian


If you are not using an IGP you would need a static route because the network statement would only come into effect after the BGP peering has been setup. But to setup the BGP peering each router needs to know how to reach the loopback. So it's a kind of catch 22 situation.


Jon

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Correct Answer
Jon Marshall Wed, 02/18/2009 - 14:37
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Ivian


If you are not using an IGP you would need a static route because the network statement would only come into effect after the BGP peering has been setup. But to setup the BGP peering each router needs to know how to reach the loopback. So it's a kind of catch 22 situation.


Jon

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