- iBGP loop prevention
- filters routes by default
- Routes learned via iBGP cannot be passed on to additional iBGP neighbors.
- Requires full mesh or confederation.
- filters routes by default
- Full mesh advantage:
- All BGP peers learn all paths.
- All BgP peers know closest egress.
- Hot Potato Routing.
- Full mesh disadvantage:
- Does not scale, too many peerings.
- Partial mesh
- mesh, route reflector and confed can interoperate.
- advantageous for scaling
- can use RR and pockets of full mesh.
- Route Reflector
- RFC 4456
- RR summarizes routing information and only reflects best path.
- IGP metrics are taken into account typically with route reflectors.
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