Where Is OSPF Used?

How many tables are there in OSPF?

three tablesEach OSPF router stores routing and topology information in three tables: Neighbor table – stores information about OSPF neighbors.

Topology table – stores the topology structure of a network.

Routing table – stores the best routes..

How does OSPF find shortest path?

OSPF routers rely on cost to compute the shortest path through the network between themselves and a remote router or network destination. The shortest path computation is done using Djikstra’s algorithm. This algorithm isn’t unique to OSPF.

Can you use RIP and OSPF together?

Adding OSPF to the Center of a RIP Network A common first step in converting a RIP network to OSPF is to add backbone routers that run both RIP and OSPF, while the remaining network devices run RIP. These backbone routers are OSPF autonomous system boundary routers.

How does OSPF determine route cost?

OSPF Metric costCost = Reference bandwidth / Interface bandwidth in bps.Cost = 108/interface bandwidth in bps.Default cost of essential interfaces.Cost of common lines.Cumulative cost = Sum of all outgoing interfaces cost in route.Best route for routing table = Route which has the lowest cumulative cost.More items…•

What is OSPF and how it works?

Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS). … OSPF is a widely used IGP in large enterprise networks.

How do I view OSPF?

To display general information about Open Shortest Path First (OSPF) routing instances, use the show ip ospf command. Use the show ip ospf command to display information about one or more OSPF instances.

What are OSPF States?

Those states are defined in the OSPF RFC 2328. , section 10.1. The states are Down, Attempt, Init, 2-Way, Exstart, Exchange, Loading, and Full.

How does OSPF choose the best path?

If there are multiple routes to a network with the same route type, the OSPF metric calculated as cost based on the bandwidth is used for selecting the best route. The route with the lowest value for cost is chosen as the best route.

Does OSPF process clear IP?

To clear redistribution based on the OSPF routing process ID, use the clear ip ospf command in privileged EXEC mode. Syntax Description pid (Optional) Process ID. OSPF counters. …

Which layer is OSPF?

network layerOSPF is developed by Internet Engineering Task Force (IETF) as one of the Interior Gateway Protocol (IGP), i.e, the protocol which aims at moving the packet within a large autonomous system or routing domain. It is a network layer protocol which works on the protocol number 89 and uses AD value 110.

Why OSPF is better than Rip?

Unlike RIP protocol that has only 15 hops at most, OSPF has no limitations in hop count. So OSPF converges faster than RIP, and has better load balancing. The drawbacks of OSPF, however, is that it doesn’t scale when there are more routers added to the network.

What is IP OSPF cost?

Use the ip ospf cost command to configure the cost metric manually for each interface. This command overrides any settings for the reference bandwidth that you set using the reference-bandwidth command in router configuration mode.

Is OSPF a layer 3 protocol?

At Layer 3, routers will use dynamic routing protocols (generally Open Shortest Path First or OSPF and BGP in most enterprises) to present a robust network that handles site-to-site link failures and minimizes the burden of IP management.

Is OSPF Classful or classless?

Classful routing protocols do not carry subnet masks; classless routing protocols do. Older routing protocols, including RIP and IGRP, are classful. Newer protocols, including RIP-2, EIGRP, and OSPF, are classless.

Why RIP protocol is used?

Stands for “Routing Information Protocol.” RIP is a protocol used by routers to exchange routing information on a network. Its primary functions are to 1) determine the most efficient way to route data on a network and 2) prevent routing loops.

Does OSPF use hop count?

Like EIGRP, OSPF bases its metric by default on link bandwidth, so that OSPF makes a better choice than simply relying on the router hop-count metric used by RIP. But OSPF uses much different internal logic, being a link-state routing protocol rather than a distance vector protocol.

How does OSPF cost work?

Open Shortest Path First (OSPF) uses “Cost” as the value of metric and uses a Reference Bandwidth of 100 Mbps for cost calculation. The formula to calculate the cost is Reference Bandwidth divided by interface bandwidth. For example, in the case of 10 Mbps Ethernet , OSPF Metric Cost value is 100 Mbps / 10 Mbps = 10.

What are the benefits of OSPF protocol?

OSPF supports/provides/advantages –Both IPv4 and IPv6 routed protocols.Load balancing with equal cost routes for same destination.VLSM and route summarization.Unlimited hop counts.Trigger updates for fast convergence.A loop free topology using SPF algorithm.Run on most routers.Classless protocol.