I recently learnt that Route reflectors are an efficient alternative to full mesh IBGP peering in a large AS. Imagine a network like: D1 - AS1 <e> R_P <i> RR <i> R_Q <e> AS3 - D3
- D1 and D3 are public networks known to AS1 and AS3.
- R_P, RR and R_Q are from AS2. RR is a route reflector.
- <e> eBGP peering
- <i> iBGP peering
When R_P advertises D1 (learnt via eBGP) to RR which in turn advertises it to R_Q, the next hop for D1 will be R_P (assume it has next-hop-self configured). So, when R_Q needs to route traffic destined for D1, it will have to do a recursive route lookup for R_P (the next hop for that route). This is not possible without an IGP/static route right ?