in above diagram neighbor relationship/peer relations are so
R1--->R2
R1--->R3
R2 and R3 are not directly or even indirectly (through R1)peer
R2--->R4
R3--->R6
R4 and R6 are not connected so they are no peers
R4--->R5
R6--->R7
R5--->R7
no problem so far, everything works just fine, R2 sees both 55.55 networks of AS 2000 and 77.77 networks of AS 1000,through their just one and only exit interfaces!!
R2#show ip bgp
Network Next Hop Metric LocPrf Weight Path
> 55.55.1.0/24 10.1.24.4 0 3000 2000 i
> 55.55.2.0/24 10.1.24.4 0 3000 2000 i
> 77.77.1.0/24 10.1.24.4 0 3000 2000 1000 i
> 77.77.2.0/24 10.1.24.4 0 3000 2000 1000 i
R3#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
> 55.55.1.0/24 10.1.36.6 0 3000 1000 2000 i
> 55.55.2.0/24 10.1.36.6 0 3000 1000 2000 i
> 77.77.1.0/24 10.1.36.6 0 3000 1000 i
> 77.77.2.0/24 10.1.36.6 0 3000 1000 i
but the problem is when I add a link between R2 and R3 and make them peer instead of seeing 2 path to each of 55.55 and 77.77 network they just see one of them like that(2 paths) and for the other one just on path I mean
R2(config-router)#do sh ip bgp
Network Next Hop Metric LocPrf Weight Path
> 55.55.1.0/24 10.1.24.4 0 3000 2000 i
> 55.55.2.0/24 10.1.24.4 0 3000 2000 i
>i77.77.1.0/24 10.1.23.3 0 100 0 3000 1000 i
10.1.24.4 0 3000 2000 1000 i
>i77.77.2.0/24 10.1.23.3 0 100 0 3000 1000 i
10.1.24.4 0 3000 2000 1000 i
to my understanding R2 supposed to learn 55.55 networks through R3 as well I mean from this path R3-->R6-->R7-->R5 since these routers are peer and R6 also has got the routes to 55.55 network and R7 got those too and so on, why we do not see a path through that way? and also on R3
R3(config-router)#do sh ip bgp
Network Next Hop Metric LocPrf Weight Path
>i55.55.1.0/24 10.1.23.2 0 100 0 3000 2000 i
10.1.36.6 0 3000 1000 2000 i
>i55.55.2.0/24 10.1.23.2 0 100 0 3000 2000 i
10.1.36.6 0 3000 1000 2000 i
> 77.77.1.0/24 10.1.36.6 0 3000 1000 i
> 77.77.2.0/24 10.1.36.6 0 3000 1000 i
and also R3 supposed to learn 77.77 networks through R2 as well I mean R2-->R4-->R5-->R7 but why this is not happening? BTW I know the best practice is to have full iBGP between routers in the AS and also I know that we'd better have direct link between those edge routers so that no need to state or overstate the obvious best practices just answer the question straight to the point thanks.