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As Internet continues to grow in size, it is important to
select the best routing path as quickly as possible. The
Internet is composed of a set of Autonomous Systems (ASs) ,
where each AS consists of routers and networks under one
administrative autho- rity. The Interior Gateway Protocols
(IGPs) are used by Internet routers to build routing tables and
distribute routing informat- ion inside an AS. In the
Transmission Control Protocol/ Internet Protocol (TCP/IP)
network, an IGP usually implements either the Distance-Vector
Routing (DVR) or the Link-State Routing (LSR) algorithm. In
DVR, a router knows the length of the shorest path from each of
its neighbors to every destination in the Internet, and uses
this information to compute its own distance and next router to
each destination. In LSR, a router must know the enti- re
network or the Internet topology because routes are computed
locally. The DVR-based Routing Information Protocol (RIP) is
the most popular IGP in use, where the LSR-based Open Shortest
Path First (OSPF) is a proposed new IGP. In this thesis, RIP
and OSPF are compared by using the performance criteria of
bandwidth consumption(message size) and updating time (routing
table updating time) . The efficiency and effectiveness of both
routing algorithms are analyzed with resp- ect to different
network topologies. Their robustnessis discuss- ed upon network
failures. Two improved algorithms, RIP* and OSPF*, are proposed
to overcome the shortcomings of RIP and OSPF*, respectively.
Both RIP* and OSPF* perform much better than the the original
algorithms. A list of guideline about how to choose and
implement the Internet routing algorithms is also suggested.
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