Ccna training comprehensive guide on ospf routing protocol. This tutorial introduces you to open shortest path first ospf, a linkstate routing protocol. Particularly it is a link state routing protocol and includes into the group of interior gateway protocol. Open shortest path first ospf is a recent entry into the internet interior routing scene. Routing information protocol rip routing information protocol rip is a standardized distance vector protocol, designed for use on smaller networks. Sanctioned by the ietf, it is intended to become internets preferred interior routing protocol. The open shortest path first ospf protocol is a link state protocol that handles routing for ip traffic.
Routing protocol packets are sent with type of service tos of 0. Open shortest path first ospf is an open standard not proprietary and it will run on most routers independent of make. Open shortest path first open shortest path first ospf is an openstandard link state routing protocol. Its an interior gateway protocol igp meaning it been designed to be used within a single autonomous system. Ospf basics and features link state routing protocol fast convergence basic ospf operation ospf neighbor discovery process ospf packet types and format ospf network topology. Comparison of rip, ospf and eigrp routing protocols based on. In this lab, you will set up a network that utilizes ospf as its routing protocol. Nonbroadcast multiaccess nbma is a particular challenge in any network environment. Open shortest path first a routing protocol based on the linkstate algorithm objective the objective of this lab is to configure and analyze the performance of the open shortest path first ospf routing protocol. Routing protocol is ospf 1 outgoing update filter list for all interfaces is not set.
Bgp pdf created with fineprint pdffactory pro trial version. Open shortest path first ospf inetdaemons it tutorials. It is used to allow routers to dynamically learn routes from other routers and to advertise routes to other routers. They take different approaches to share routing updates. Learn ospf configuration commands, ospf show commands, ospf network configuration process id, network id, wild card mask and area number and ospf routing in detail. Ospf tutorial december 3rd, 2010 go to comments for example, r1 wants to find out if it has any neighbor running ospf it sends a hello message to the multicast address 224. Open shortest path first ospf is an open standard not proprietary and it. Sep 19, 2018 open shortest path first ospf is a widely used and supported routing protocol. Hop count is the metric that rip uses and the hop limit limits the network size that rip can support. The main difference here is that a linkedstate protocol does not send its routing table in the form of updates, but only shared its connectivity configuration. The ospf protocol is a linkstate routing protocol, which means that the routers exchange. Open shortest path first ospf routing protocol dummies.
Routing protocol is ospf 1 outgoing update filter list for all interfaces is not set incoming update filter list for all interfaces is not set router id 192. Ospf is a routing protocol used to determine the best route for delivering the packets within an ip networks. Ospf version 2 is documented in rfc 1583 a lengthy document that i find very difficult to read. The version 2 of open shortest path first ospf defined in 1998 for. The router ospf command enables ospf routing on the router, and the 1 before osfp is the process id of the osfp protocol. Ospf routes packets based entirely on the destination ip of the. Optional md5 authentication configured ip ospf authentication messagedigest ip ospf messagedigestkey 1 md5 foobar. Dec 03, 20 default routes in ospf, default route configuration with cost, ospf special area types duration. By using various parameters such as the autonomous system and metric it locates a better path and all types of protocols have their own pros and cons. You should know how to define a routing protocol and understand which protocol is best to use in your network. Define area 9 as a totally stubby area area 9 stub nosummary. You can set different process id from 165535 for each router. Ospf open shortest path first link state or spf technology. It can also be called an act of approach to a state where all routing tables have detailed information are in steadystate.
Ospf and isis in common they both maintain a link state database from which a dijkstrabased spf algorithm computes a shortestpath tree they both use hello packets to form and maintain adjacencies they both use areas to form a twolevel hierarchical topology they both have the capability of providing address summarization between areas they both are classless protocols support vlsm. This paper examines how ospf works and how it can be used to design and build large and complicated networks. External route routes imported into ospf from other protocol or static. Ospf was originally defined as the 2 nd version in rfc 2328. Route redistributionroutes learned via any ip routing protocol can be. Rip adheres to the following distance vector characteristics. How to configure ospf routing protocol using packet tracer. Link state routing protocols advertise the state of their links.
The main purpose of the routing protocol is to find a better and accurate path for the data packet to transfer from source to destination. Apr 25, 2015 the router ospf command enables ospf routing on the router, and the 1 before osfp is the process id of the osfp protocol. In this lesson ill explain the basics of ospf to you and you will learn how and why it works. One of the most popular dynamic routing protocols available is the open shortest path first ospf. This tutorial explains how to configure ospf routing protocol step by step with practical example in packet tracer. This paper examines how ospf works and how it can be used to design and build large and. Routing protocol how it works mechanism and types of routing. Give c second priority bdr in election ip ospf priority 50 interface loopback0 ip address 10. Simple ospf network need to create ospf routing process router configuration command router ospf specify the network running ospf should also specify the area 25. Ospf is developed by internet engineering task force ietf as one of the interior gateway protocol igp, i. Home downloads download cisco ccnp routing pdf study guide. Open shortest path first ospf is a linkstate routing protocol, rather than a distance vector protocol.
This article introduced the ospf protocol and examined how ospf works. Routing protocol packets share a common protocol header routing protocol packets are sent with type of service tos of 0 five types of ospf routing protocol packets hello packet type 1 database description packet type 2 linkstate request packet type 3 linkstate update packet type 4 linkstate acknowledgement packet type 5. Isis is a linkstate interior gateway routing protocol. Open shortest path first ospf is an active routing protocol used in internet protocol. Incoming update filter list for all interfaces is not set. Rip routing information protocol is one of the oldest routing protocols still in service. Its newest implementation, version 2, which is explained in rfc 2328, is an open standard. By collecting connectivity information from all of the devices on the network, ospf. Like ospf, isis runs the dijkstra shortestpath first spf algorithm to create a database of the networks topology and, from that database, to determine the best that is, shortest path to a destination. The open shortest path first ospf protocol, defined in rfc 2328, is an interior gateway protocol used to distribute routing information within a single autonomous system. Open shortest path first ospf is a widely used and supported routing protocol. Openshortestpathfirst ospf is the most widely used interior gateway protocol routing protocol on the world because it is a public nonproprietary routing protocol while its biggest rival, eigrp, is a cisco proprietary protocol so other vendors cant use it edit. Ospf is a linkstate routing protocol with a complex set of. How to configure ospf routing protocol using cisco packet.
Routing information protocol distance vector routing share the most you know about the entire autonomous system share with all your direct neighbors, and them only share periodically, e. Ospf will form neighbor relationships with adjacent routers in the same area. 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. Rip and ospf o exterior routing n routing between autonomous systems n only one exterior routing protocol is usually used for exterior routing n examples. Ospf adheres to the following link state characteristics. Like all linkstate protocols, ospf is very efficient in its use of network. Routing protocol how it works mechanism and types of. May 19, 2018 introduction to open shortest path first ospf a tutorial open shortest path first ospf is a link state routing protocol which was first defined as version 2 in rfc 2328.
Ospf open shortest path first ospf is a standardized linkstate routing protocol, designed to scale efficiently to support larger networks. Overview in lab 6 we discussed rip, which is the canonical example of a routing protocol built on the distancevector algorithm. Ospf employs a hierarchical network design using areas. When a link state router begins operating on a network link, information associated with that logical network is added to its local link state database lsdb. When many ospf routers are part of the same network, information about all of the routes in a network are learned by all of the ospf routers within that networktechnically called an area.
Ospf tutorial to get you on the right path udemy blog. It then briefly explains why ospf is considered an improved routing protocol over routing information protocol rip by covering how ospf discovers, chooses, and maintains routing tables. Comparison of rip, ospf and eigrp routing protocols based. The chapter starts by covering the basic ospf concepts.
In this article we will learn about the ospf routing protocol. This is a linkstate algorithm protocol compared with distancevector protocols like rip and is categorized as an interior gateway protocol igp like eigrp, isis etc igp protocols are running within the same autonomous system network i. Important ospf interview questions and answers with pdf to. Eigrp has become a public routing protocol since 20. Unlike ospf, which was developed and standardized by the internet engineering task force ietf. We start with a description of only a few terms and proceed to more explanations on subsequent pages. Default routes in ospf, default route configuration with cost, ospf special area types duration. Ospf is a standardized linkstate routing protocol, designed to scale efficiently to support larger networks. Two routers speaking ospf to each other exchange information about the routes they know about and the cost for them to get there. Rip was one of the first true distance vector routing protocols, and is supported on a wide variety of systems.
Introduction to open shortest path first ospf protocol. Open shortest path first ospf operating inside a distinct autonomous system. It was published by the ietf to serve as an interior gateway protocol replacing rip. Ospf routing messages ospf exchanges messages using directly ip packets with a protocol number 89 in the corresponding eld of the ip header hello. Three typical types of routing protocol are chosen as the simulation samples. Teaches good routing protocol design practices isis relaxed two level design l2 routers must be linked through the backbone suits isps with stringy networks, diverse infrastructure, etc, not fitting central core model of ospf more flexible than ospf, but easier to make mistakes too. Basic ospf configuration for internal router abr and asbrs 44. Open shortest path first ospf is a link state routing protocol which was first defined as version 2 in rfc 2328. Ospf open shortest path first is a popular linkstate routing protocol. Routing protocol with fast convergence time is preferable because disturbance can occur during the router spends time in calculating networks for the optimal path. It uses a routing algorithm at link state and falls into the interior protocols for routing and operating using one autonomous system. Ospf is a linkstate routing protocol providing fast convergence and excellent scalability. We begin here a discussion of the terminology of ospf open shortest path first.
How to use and implement ospf as the protocol of choice. These lessons will teach you everything, we start with the basics and work our way through the. Interior and exterior routing o interior routing n routing inside an autonomous system n each as can chose its own interior routing protocol n examples. Ospf stands for open shortest path first and is a routing protocol adaptive for ip networks. Open shortest path first ospf is an interior gateway protocol igp standardized by the internet engineering task force ietf and commonly used in large enterprise networks.
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