Connecting an Enterprise Network to an ISP Network Comparing the Functions and Uses of EBGP and IBGP Connecting an Enterprise Network to an ISP Network

BGP Neighbors A “BGP neighbor” is also known as a “BGP peer” TCP connection

External BGP Neighbors A BGP neighbor in a different AS

Requirements for EBGP Different AS number Defined neighbors Reachability

Internal BGP Neighbors A BGP neighbor in same AS Requirements: Same AS number Defined neighbors Reachability

Summary Every BGP router establishes a neighbor relationship with other BGP neighbors. An External BGP (EBGP) neighbor relationship is established between the routers in different autonomous systems (AS). An Internal BGP (IBGP) neighbor relationship is established between routers in the same AS.