Secure Computing SG570 Instrukcja Użytkownika Pobierz pdf (Strona 116)

OSPF

Note

This example is adapted from the LARTC (Linux Advanced Routing & Traffic Control)

dynamic routing howto, available from: http://lartc.org/howto/

LARTC is an invaluable resource for those wanting to learn about and take advantage of

the advanced routing capabilities of Linux systems.

OSPF stands for Open Shortest Path First, and some of its principal features as follows:

Networks are grouped by areas, which are interconnected by a backbone area which

will be designated as area 0. All traffic goes through area 0, and all the routers in

area 0 have routing information about all the other areas.

Routes are propagated very fast, compared with RIP, for example.

OSPF uses multicasting instead of broadcasting, so it doesn't flood other hosts with

routing information that may not be of interest for them, thus reducing network

overhead. Also, Internal Routers (those which only have interfaces in one area) don't

have routing information about other areas. Routers with interfaces in more than one

area are called Area Border Routers, and hold topological information about the areas

they are connected to.

OSPF is based on Dijkstra's Shortest Path First algorithm, which is CPU intensive

compared to other routing algorithms.

OSPF counts with the special characteristics of networks and interfaces, such as

bandwidth, link failures, and monetary cost.

In this example we set up route management using OSPF for the network topology

described by the following diagram.

110

Network Setup

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Secure Computing SG570 Instrukcja Użytkownika Strona 116