Avaya P460 Manuel D’Utilisation
Chapter 5
Avaya P460 Layer 3 Features
Avaya P460 Configuration Guide
49
OSPF (Open Shortest Path First) Configuration
OSPF Overview
OSPF is a routing protocol developed for IP networks 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 is based on the cost of a particular path. In contrast, RIP uses hops as a path
criterion. Also, updates are sent on a “need to know” basis rather than every 30
seconds as with RIP.
The advantage of shortest path first algorithms is that they results in smaller more
frequent updates everywhere. 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. In the end, the advantages out weigh the disadvantages.
Routers use link-state algorithms to send routing information to all nodes in an
internetwork by calculating the shortest path to each node. This calculation is based
on a topography of the Internet constructed by each node. Each router sends that
portion of the routing table (keeps track of routes to particular network
destinations) that describes the state of its own links, and it also sends the complete
routing structure (topography).
The P460 supports the OSPF routing protocol. You can configure the P460 as an
OSPF ASBR (Autonomous System Boundary Router) by route redistribution. The
P460 can be installed in the OSPF backbone area – area 0.0.0.0 – or in any OSPF area
that is part of a multiple areas network. However, the P460 cannot be configured to
be an OSPF area border router itself.
The P460 supports the ECMP (equal-cost multipath) feature which allows load
balancing by splitting traffic between several equivalent paths.
While you can activate OSPF with default values for each interface using a single
command, you can configure many of the OSPF parameters.
For a detailed description of OSPF, see the OSPF standards and published literature.
first or link-state algorithm. It was introduced to overcome the limitations of RIP in
increasingly complex network designs.
OSPF is based on the cost of a particular path. In contrast, RIP uses hops as a path
criterion. Also, updates are sent on a “need to know” basis rather than every 30
seconds as with RIP.
The advantage of shortest path first algorithms is that they results in smaller more
frequent updates everywhere. 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. In the end, the advantages out weigh the disadvantages.
Routers use link-state algorithms to send routing information to all nodes in an
internetwork by calculating the shortest path to each node. This calculation is based
on a topography of the Internet constructed by each node. Each router sends that
portion of the routing table (keeps track of routes to particular network
destinations) that describes the state of its own links, and it also sends the complete
routing structure (topography).
The P460 supports the OSPF routing protocol. You can configure the P460 as an
OSPF ASBR (Autonomous System Boundary Router) by route redistribution. The
P460 can be installed in the OSPF backbone area – area 0.0.0.0 – or in any OSPF area
that is part of a multiple areas network. However, the P460 cannot be configured to
be an OSPF area border router itself.
The P460 supports the ECMP (equal-cost multipath) feature which allows load
balancing by splitting traffic between several equivalent paths.
While you can activate OSPF with default values for each interface using a single
command, you can configure many of the OSPF parameters.
For a detailed description of OSPF, see the OSPF standards and published literature.
OSPF CLI Commands
In order to...
Use the following command...
Enable OSPF protocol
Configure the area ID of the router