1.3 Moving Packets

Computers use and provide services by exchanging packets. Packet exchange can be accomplished only if the computers know how to move information amongst themselves. Computers learn the path, or route, to other computers by using routing protocols such as the following:

There are two kinds of routing protocols, distinguished by their mode of best route discovery:

Distance vector routing protocols determine the best route from one computer to another based on the distance, or number of hops, and the time, or ticks, that separate hosts. Link state routing protocols use a cost metric to determine the best path between hosts.

Link state routing protocols are generally more accurate and efficient than distance vector routing protocols and are better suited for traversing WAN links. The table below shows the protocol and routing types associated with the routing protocols:

Routing Protocol

Protocol Type

Routing Type



Link State



Link State


IP and IPX

Distance Vector



Distance Vector

Open Shortest Path First (OSPF) is a link state IP routing protocol. Its IPX equivalent is NetWare Link Service Protocol™ (NLSP™). Routing Information Protocol (RIP) is a distance vector routing protocol used for both IP and IPX routing, but with some variation between protocols. RIP II is a newer IP routing protocol based on RIP that adds support for a subnet mask.