BGP roles include:

• Because it is a PVP, BGP communicates the entire autonomous system/network path topology to other networks
• Maintains its routing table with topologies of all externally connected networks
• Supports classless interdomain routing (CIDR), which allocates Internet Protocol (IP) addresses to connected Internet devices

When used to facilitate communication between different autonomous systems, BGP is referred to as External BGP (EBGP). When used at host networks/autonomous systems, BGP is referred to as Internal BGP (IBGP).

BGP was created to extend and replace Exterior Gateway Protocol (EGP).