OPEN SHORTEST PATH
FISRT PROTOCOL
OSPF
INTRODUCTION
OSPF – is link state routing protocol
It calls for sending link state advertisements (LSAs)
to all other routers within the same hierarchical
area.
Information on attached interfaces, metrics used
and other variables is included in OSPF LSAs.
They use SPF routing algorithm- link state routing
protocol – contradicts with RIP & IGRP – DVR.
ROUTING HIERARCHY
Unlike RIP, OSPF can operate within
hierarchy. The largest entity within hierarchy
is the autonomous systems (AS), which is a
collection of networks under a common
administration that share a common routing
strategy.
OSPF is an intra-AS ( interior gateway)
routing protocol, although it is capable of
receiving routes from and sending routes to
other AS’s.