What is the difference between BGP (Border Gateway Protocol) and IGP (Interior Gateway Protocol) ?

BGP is the only Exterior Gateway Protocol (EGP) and it is used to route traffic between networks with different Autonomous System Number (ASN).

IGPs are (RIP-1&2, OSPF or EIGRP) and they are used to route taffic between networks with the same ASN, this is the major difference.

Well there are2 kinds of protocol:

a. Exterior gateway Protol (EGP): It was used in early1990

b. Interior Gateway Protol (IGP): It works inside an Autonomous System (ASN)

Currently EGP is not available.Instead of EGP there is a new protocol taken place called eBGP.Many people think BGP is an EGP.But really it is not.eBGP is the successor of EGP

There are two kinds of BGP:

a. eBGP:

b. iBGP

eBGP is now only one protocol that works between two different ASN,

There are other protocols like RIP,EIGRP,OSPF.iBGP are IGP because they work inside an ASN.

BGP(border gateway protocol)it is used between the autonomous system(as) where as igp (interior gateway protocol)are used within the as(autonomous system)

IGP protocols are (rip1,rip2,eigrp,ospf)

BGP exchange routes between different AS numbers while IGP exchange routes with in the same AS number

routers shouls use IGP such as OSPF and EIGRP to communicate with other routers in the same autonomous system and use BGP to  communicate with other routers outside the border the  autonomous system.

igp(interior gateway protocole):- it's using with in same autonomous synchronous no

exam:  rip,eigrp,ospf

EGP(exterior routing protocole)

it's use between autonomous synchronous no

exam :bgp(border gateway protocole

I think there is a mistake in the question. It should be like difference between IGP (Interior Gateway Protocol ) and EGP (Exterior Gateway Protocol). 

IGP is used in a single administration domain (i.e. in single AS). Examples of IGP are RIP, IGRP, EIGRP & OSPF.

IGP has2 categories. Distance Vector (Hop Count, RIP is the example) Other is Link State (It checks the health of link in order to choose the path, OSPF is the example).

EGP is used between AS to AS. Example of EGP is BGP.