Sessions And Peers - Dell Force10 S4810P Configuration Manual

Since each BGP router talking to another router is a session, a BGP network needs to be in "full mesh".
This is a topology that has every router directly connected to every other router . Each BGP router within an
AS must have iBGP sessions with all other BGP routers in the AS. For example, a BGP network within an
AS needs to be in "full mesh." As seen in
each, six routers have 5 peers each, and eight routers in full mesh will have seven peers each.
Figure 9-2. Full Mesh Examples
4 Routers
The number of BGP speakers each BGP peer must maintain increases exponentially. Network
management quickly becomes impossible.

Sessions and Peers

When two routers communicate using the BGP protocol, a BGP session is started. The two end-points of
that session are Peers. A Peer is also called a Neighbor.
176
| Border Gateway Protocol
Figure 9-2, four routers connected in a full mesh have three peers
8 Routers
6 Routers