How do we configure OSPF routing protocol?

How do we configure OSPF routing protocol?

Configuring OSPF in a Single Area

1. Use the command router ospf process ID to start OSPF.
2. Use the network command to enable the interfaces.
3. Identify area assignments.
4. (Optional) Assign the router ID. Example 3-1 displays OSPF with a process ID of 1 and places all interfaces configured with an IP address in area 0.

What are the 7 stages of OSPF?

The states are Down, Attempt, Init, 2-Way, Exstart, Exchange, Loading, and Full.

How OSPF works step by step?

How does OSPF work?

1. There are three steps that can explain the working of OSPF:
2. Step 1: The first step is to become OSPF neighbors.
3. Step 2: The second step is to exchange database information.
4. Step 3: The third step is to choose the best route.

How configure multiple areas in OSPF?

This time, we’ll take a look how you can configure multi area OSPF. Above we have R1 and R2 in area 0, the backbone area. Between R1 and R3, we will use area 1 and between R2/R4 we will use area 2. R3 and R4 have a loopback interface with an IP address that we will advertise in their area.

What is OSPF protocol?

Open Shortest Path First (OSPF) is a link-state routing protocol that was developed for IP networks and is based on the Shortest Path First (SPF) algorithm. OSPF is an Interior Gateway Protocol (IGP).

What is OSPF example?

A simple two-router OSPF network

Here’s an example of a network configuration that creates a very simple OSPF network between two Cisco routers. The routers are placed in area 0 and an OSPF point-to-point link is configured between them. R1 will announce the 1.1. 1.1/32 route and R2 will announce 2.2.

What are the 5 types of OSPF packets?

Packet types for OSPF

• Hello packet. This packet is sent by the OMPROUTED server to discover OSPF neighbor routers and to establish bidirectional communications with them.
• Database description packet.
• Link-state update packet.
• Link-state request packet.
• Link-state acknowledgment packet.

Which layer is OSPF?

The OSI Seven Layer Model

Which 3 features are OSPF routing protocol?

OSPF bases link cost on bandwidth to determine the best route. OSPF is a distance vector type of protocol. OSPF uses DUAL algorithm for route computation. OSPF updates are event triggered.

What is OSPF Area 0 called?

Backbone Area This is the central area in your OSPF routing domain which all areas must connect to. This area is labeled area 0 (or the longhand version 0.0. 0.0).

What are OSPF area types?

There are five types of OSPF areas: Backbone area (area 0), Standard area, Stub area, Totally stubby area, and No so stubby area (NSSA).

Why is OSPF used?

The OSPF (Open Shortest Path First) protocol is one of a family of IP Routing protocols, and is an Interior Gateway Protocol (IGP) for the Internet, used to distribute IP routing information throughout a single Autonomous System (AS) in an IP network.

What port does OSPF use?

port 89
OSPF uses an port at the IP layer ie. port 89 so it does not use TCP for reliable delivery. So to ensure reliable delivery of LSAs OSPF uses implicit and explicit acknowledgement of transmitted LSAs.

How many states are in OSPF?

OSPF has to get through 7 states in order to become neighbors… here they are: Down: no OSPF neighbors detected at this moment. Init: Hello packet received.

Is OSPF TCP or UDP?

OSPF messages ride directly inside of IP packets as IP protocol number 89. Because OSPF does not use UDP or TCP, the OSPF protocol is fairly elaborate and must reproduce many of the features of a transport protocol to move OSPF messages between routers.

How many routes can OSPF handle?

We very often see customers running OSPF in topologies way more complex than this and carrying between 4000 and 6000 routes (without any kind of summarization) without too many issues.

What are LSA types?

LSA Types – Quick Overview

• LSA Type 1: OSPF Router LSA.
• LSA Type 2: OSPF Network LSA.
• LSA Type 3: OSPF Summary LSA.
• LSA Type 4: OSPF ASBR Summary LSA.
• LSA Type 5: OSPF ASBR External LSA.
• LSA Type 6: OSPF Group Membership LSA.
• LSA Type 7: OSPF Not So Stubby Area (NSSA) External LSA.

What is E1 and E2 in OSPF?

E1 routes indicate cumulative cost to reach the destination i.e. int indicates cost to reach ASBR + cost to destination from ASBR. E2 route reflects cost only from the ASBR to destination. This is the default used by ospf for redistribution.

Is OSPF Layer 4?

OSPF is implemented as a layer 4 protocol, so it sits directly on top of IP. Neither TCP nor UDP are used, so to implement reliability OSPF has a checksum and its own built-in ACK. To troubleshoot by sniffing traffic, we need to know that the OSPF multicast address is 224.0.

What is the area 0 in OSPF?

Backbone Area This is the central area in your OSPF routing domain which all areas must connect to. This area is labeled area 0 (or the longhand version 0.0. 0.0). When traffic needs to pass from one area to another, it must traverse the backbone.

What is N1 and N2 in OSPF?

E1 or E2 or N1 or N2 type routes are based upon cost of the route. E2 or N2 routes tell OSPF routers to set the metric as the metric at the point of redistribution.(At the ASBR) E1 or N1 routes tell OSPF routers to add the internal costs to reach the ASBR to the cost set at the point of redistrbution (At the ASBR)

What is E1 E2 and N1/N2 routes in OSPF?

Introduction to OSPF Routes
E1 are the route when the cost of the internal links is taken into consideration for SPF calculation. E2 are the routes which take only the external link cost into the SPF calculation.

Which OSI layer is OSPF?

4 Transport
The OSI Seven Layer Model

What is OSPF router ID?

Each OSPF router selects a router ID (RID) that has to be unique on your network. OSPF stores the topology of the network in its LSDB (Link State Database) and each router is identified with its unique router ID , if you have duplicate router IDs then you will run into reachability issues.

Which route is preferred E1 or E2?

You can have ASBR 1 inject the external route as E1 and ASBR 2 inject the same external prefix as an E2 route. Due to the order of operations of OSPF, the E1 route will always be preferred regardless of the cost to the ASBR. But in case of single point of redistribution, it doesn’t matter what route type you use.