Role of EGP and BGP in the TCP/IP (Exterior Routing Protocols)

Both EGP and BGP are types of or used as Exterior Routing Protocols
EGPs provide routing between autonomous systems.

EGP:
The first widespread exterior routing protocol was the Exterior Gateway Protocol. EGP provides dynamic connectivity but assumes that all autonomous systems are connected in a tree topology. This was true in the
early Internet but is no longer true.
Although EGP is a dynamic routing protocol, it uses a very simple design. It does not use metrics and therefore cannot make true intelligent routing decisions. EGP routing updates contain network reachability information. In other words, they specify that certain networks are reachable through certain routers. Because of its limitations with regard to today's complex internetworks, EGP is being phased out in favor of routing protocols such as BGP.

BGP:

BGP represents an attempt to address the most serious of EGP's problems. Like EGP, BGP is an interdomain routing protocol created for use in the Internet core routers. Unlike EGP, BGP was designed to prevent
routing loops in arbitrary topologies and to allow policy−based route selection.
BGP was co−authored by a Cisco founder, and Cisco continues to be very involved in BGP development. The latest revision of BGP, BGP4, was designed to handle the scaling problems of the growing Internet.