RIP & BGP

[manumohan200]

In the book Routing TCP/IP Volume 1 by Jeff Doyle,he has mentioned in the second chapter that RIP & BGP although they are routing protocols they work at the application layer.Why? If so where do OSPF ,EIGRP and IGRP work in the OSI layers ?

[ruwhite]

I suppose you could argue that a routing protocol is an application that runs on top of the network, OSPF, EIGRP, IS-IS, RIP, and BGP included. In a sense, they are, because they rely on connectivity provided by the network to move infomation--BGP is probably the most reliant, and probably comes closest to the application layer.

On the other hand, I would classify routing protocols as operating at layer 3, even though they are applications that operate at layer 3, because they provide the information required to make the layer 3 and above parts of the network actually work.

:-)

Russ.W

[Harold Ritter]

RIP uses UDP port 520 and BGP uses TCP port 179.

OSPF, EIGRP and IGRP all run directly on top of IP and each have a separate IP protocol number (89, 88 and 9).

Hope this helps,