in this topology , bgp neighbor is not done between R1 & R3 & Both Ro

[krahulbgp]

in this topology , bgp neighbor is not done between R1 & R3 & Both Router are not even configured by static route ,Will R1 be reachable with R3 in this case

[Georg Pauwen]

Hello,

R1 is reachable from R3; since you announce the 1.0.0.0/8 network on R1, R3 receives that route.

[MHM Cisco World]

Show ip route,

If you see

Router id or any interface ip of other router then other router reachable.

[Flavio Miranda]

Hi

 As R1 and R3 are in different autonomous system ,therefore, they are eBGP routers, they will not form neighborhood unless you enter the command "ebgp-multihop " Of course, they must have recheability and you need to add both as a neighbor.

R1:

R1(cofig)# router bgp 650014

R1(cofig)# router bgp neighbor 1.1.1.1  remote-as 650003

R1(cofig)# router bgp neighbor 1.1.1.1  ebgp-multihop 2

R3:

R3(cofig)# router bgp 650003

R3(cofig)# router bgp neighbor 2.1.1.2 remote-as 650014

R3(cofig)# router bgp neighbor 2.1.1.2 ebgp-multihop 2

[paul driver · Accepted solution]

Hello

R1/R3 should be reachable between each other via their connected peerings of R2/R4

[krahulbgp]

If it is than why we need this command which is mentioned in above trail reply ,getting confused on this