I am facing a strange issue (all routers are linux with bird runnning).

My topology(RING Topology) is as below,

R1 ------------R2------------R3---------R4

BGP is running on all nodes.

R1 to R3 route is going via R1--R2--R3 and the return path is in also in same path (R3--R2----R1), then  thing works fine

But suppose,

R1 to R3 path is  R1---R2---R3 and  return path is  R3----R4---R1.  then  traffic is not passing.

Any configurations i should do in linux ?