Configuring Ospf; Overview Of Ospf - Avaya G250 Administration

Configuring the router
Use the network command to specify a list of networks on which the RIP is running. Use
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the no form of this command to remove an entry from the list of networks.
Use the redistribute command to redistribute routing information from other protocols
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into RIP. Use the no form of this command to restore the default value, disable
redistribution by RIP.
Use the router rip command to enable RIP and to enter the router configuration
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context. Use the no form of this command to restore the default value, disabling RIP.
Use the timers basic command to set RIP timers. Use the no form of this command to
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set the RIP timers to their default values.

Configuring OSPF

This section provides information about configuring OSPF parameters for router interfaces and
contains the following topics:

Overview of OSPF

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OSPF dynamic cost
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manually configure the cost of an OSPF interface
OSPF limitations
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OSPF commands
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the G250/G350
Overview of OSPF
The Open Shortest Path First (OSPF) protocol enables routers to compute the path that an IP
packet should follow. Routers exchange routing information with OSPF to determine where to
send each IP packet on its next hop. RIP is an older protocol that serves a similar purpose. For
more information about RIP, see
OSPF is based on the shortest-path-first or link-state algorithm. It was introduced to overcome
the limitations of RIP in increasingly complex network designs. OSPF uses the cost of a path as
the criterion for comparing paths. In contrast, RIP uses the number of hops as the criterion for
comparing paths. Also, updates are sent when there is a topological change in the network,
rather than every 30 seconds as with RIP.
The advantage of shortest-path-first algorithms is that under stable conditions, there are less
frequent updates (thereby saving bandwidth). They converge quickly, thus preventing such
problems as routing loops and Count-to-Infinity, when routers continuously increment the hop
count to a particular network. These algorithms make a stable network. The disadvantage of
shortest-path-first algorithms is that they require a lot of CPU power and memory.
348 Administration for the Avaya G250 and Avaya G350 Media Gateways
— an overview of OSPF
— a description of OSPF cost calculation, with instructions on how to
— a description of the limitations on the use of OSPF on the G250/G350
— a list and descriptions of CLI commands used to configure OSPF on
RIP overview on page 344.