This article introduced the ospf protocol and examined how ospf works. Ospf also provides for the authentication of routing updates. A 32bit number assigned to each router running the ospf protocol. How to configure ospf routing protocol using cisco packet. Generatingadefaultroute24 configuringlookupofdnsnames25 forcingtherouteridchoicewithaloopbackinterface25 controllingdefaultmetrics26. The book focuses on ospf open shortest path first, a common tcpip routing protocol that provides robust and efficient routing support in the most demanding internet environments. Ospf open shortest path first ospf is a standardized linkstate routing protocol, designed to scale efficiently to support larger networks.
The example below shows ospf configuration on an ex series with one area. To view or download the pdf version of this document, select open shortest path first. Ospf is classified as an interior gateway protocol igp. Open shortest path first ospf protocol is a diverse and scalable routing protocol that is able to detect the updown state of links in an environment and update linkstate tables as appropriate. Ospf adheres to the following link state characteristics. It is defined as ospf version 2 in rfc 2328 1998 for ipv4.
In this case, the aggregated ethernet interfaces are included in area 1. Ospf neighbor states ospf neighbor forming process. Ospf in detail isp workshops last updated 29 october 20 1. What this means is that you can run ospf in a network consisting of multivendor devices. Pdf open shortest path first ospf routing protocol. Introduction this document is a specification of the open shortest path first ospf tcpip internet routing protocol.
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. This paper examines how ospf works and how it can be used to design and build large and complicated networks. Open shortest path first open shortest path first ospf is an openstandard link state routing protocol. Supported by practically every routing vendor, as well as the open source community, ospf is one of the few protocols in the it industry you can count on being available just about anywhere you might need it. Internal gateway protocol igp, routing information protocol rip, variable length subnet masks vlsm introduction. Frrouting frr is an ip routing protocol suite for linux and unix platforms which includes protocol daemons for bgp, isis, ldp, ospf, pim, and rip. Ospf overview, history, standards and versions page 1 of 2 in the early days of tcpip, the routing information protocol rip became the standard protocol for routing within an autonomous system as, almost by default. Open shortest path first ospf is a routing protocol for internet protocol ip networks. Ospf overview, history, standards and versions tcpip guide.
This report discusses about the ospf protocol, its advantages, some issues faced while designing large ospf networks. By default, the firewall does not use ospf authentication for the exchange between ospf neighbors. Ospf open shortest path first link state or spf technology developed by ospf working group of ietf rfc 1247 ospfv2 ipv4 standard described in rfc2328 ospfv3 ipv6 standard. Download cisco ccnp routing pdf study guide snabay networking. Perhaps it is the widely used interior gateway protocol in a large enterprise. Ospf will form neighbor relationships with adjacent routers in the same area. 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. A simulation of the ospf flooding protocol, using 20, 50 and 80 router pointto point networks, shows three results. Contents chapter 1 readmefirst1 chapter 2 configuringospf3 findingfeatureinformation3 informationaboutospf4 ciscoospfimplementation4 routercoordinationforospf4. Th is number uniquely identifies the router within an autonomous system. Bgp version 4 bgpv4 is the current standard deployment.
Open shortestpathfirst 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. Apr 25, 2015 good, the basic configuration has competed and now start configure ospf routing protocol on this network. Router use this number to identify themselves when. For linkstate routing protocol, it is required that the linkstate databases for all routers remain synchronized. Ospf employs a hierarchical network design using areas. Comparison of rip, ospf and eigrp routing protocols based on. Ospf is a common tcpip internal gateway protocol igp used to distribute routing. The most popular routing protocols used on internet protocol ip networks and internetworks, including routing information protocol rip, open shortest path first ospf, border gateway protocol bgp, and private networknetwork interface pnni.
Ospf open shortest path first is the most widely used igp interior gateway protocol large enterprise networks. Ospf basics and features link state routing protocol fast convergence. Th synchronization starts as soon as the adjacency is formed between neighbors. Optionally, you can configure ospf authentication between ospf neighbors by either a simple password or using md5 authentication. Eigrp enhanced interior gateway routing protocol is ciscos proprietary routing protocol based on. Download cisco ccnp routing pdf study guide snabay. The user must provide the ip and snmp community string of a single ospf device in the network for example, a device in the core and the script searches for all other ospf routers. Gateway routing protocol eigrp is an example of a balanced hybrid routing protocol. Ospf is a linkstate routing protocol with a complex set of options and features. Ospf is a standardized linkstate routing protocol, designed to scale efficiently to support larger networks. 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. The lab is ready for routing, download and configures ospf routing with the following step by step guide. 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.
It allows the discovery of all ospf network devices in the network, without connecting to each of them or knowing all their ip addresses. Many options are available for the show ip ospf command. The loopback and vlan interfaces are passive ospf interfaces. Routing protocols rip, ospf, bgp interior and exterior routing rip ospf. While ospf has traditionally been an organizational networking protocol, in these exciting times of software defined networking sdn, it has assumed an important role in the consolidated data. Hop count is the metric that rip uses and the hop limit limits the network size that rip can support. In the router r1 configure osfp routing with router ospf command. Ospf neighbor discovery process all neighboring router with ospf enabled receive the hello packet checks contents of the hello message and if certain information match it reply unicast to that hello with sending its router id in the neighbor list. To locate and download mibs for selected platforms. A simulation of the ospf flooding protocol, using 20, 50 and 80 router pointtopoint networks, shows three results.
Chapter routing protocols rip, ospf, and bgp pdf created with fineprint pdffactory pro trial version. Rip routing information protocol is one of the oldest routing protocols still in service. It uses a link state routing lsr algorithm and falls into the group of interior gateway protocols igps. 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 classless protocol, and thus supports vlsms.
The ospf protocol is based on spf or linkstate technology. Ospf uses cost as its metric, which is computed based on the bandwidth of the link. A methodical and detailed description of the protocol is offered and ospfs role within the wider context of a tcpip network is demonstrated. Introduction open shortest first path protocol preferred igp the myth. Eigrp has several advantages over routing information protocol rip and interior gateway routing protocol igrp, and even some advantages over open shortest path first ospf and intermediate systemtointermediate system isis. Ability to run multiple routing protocols in the same router same prefix could be learnt via more than one routing protocol adminstrative distance is used to discriminate between multiple source connected, static and other dynamic protocols 20. Routing protocol packets are sent with type of service tos of 0. Ospf is based on the shortest path first spf algorithm which is used to calculate the shortest path to each node.
Pdf open shortest path first ospf routing protocol simulation. An interface has state information associated with it, which is obtained from the underlying lower level protocols and the routing protocol itself. These options are listed in the following output, followed by a discussion of a few of the key ones. Configure ospf router ids the ospf router id is used to uniquely identify the router in the ospf routing domain. Basic notes on ospf open shortest path first sysnet notes.
Ospf configuration, the router sends a notification message to the console stating that a neighbor relationship with another ospf router has been established. Five types of ospf routing protocol packets hello packet type 1. Border gateway protocol border gateway protocol bgp bgp is a standardized exterior gateway protocol egp, as opposed to rip, ospf, and eigrp which are interior gateway protocols igps. Ospf uses database descriptor dbd packets for this purpose. In this lesson ill explain the basics of ospf to you and you will learn how and why it works. 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.
On multiaccess networks the hello protocol can also dynamically discoverneighboring routers. Finally, the disable option ensures that the management. Apart from being a linkstate protocol, it is also an open standard protocol. The open shortest path first ospf protocol, defined in rfc 2328, is an interior gateway protocol used to distribute routing information within. 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. Step by step guide to configure ospf routing protocol on cisco routers. Download fulltext pdf open shortest path first ospf routing protocol simulation. Ospf is hard to use evolved from isis protocol link state protocol 4. This tutorial explains how to configure ospf routing protocol step by step with practical example in packet tracer. It supports the ipv4, ipv6 networks, cidr and vlsm addressing models. Eigrp has several advantages over routing information protocol rip and interior gateway routing protocol igrp, and even some advantages over open shortest path first ospf and. A network routing protocol is an absorbing, comprehensible account of ospf, including the algorithm which is used for calculating its routes. Ospf routes have an administrative distance is 110.
Sanctioned by the ietf, it is intended to become internets preferred interior routing protocol. Rfc 2328 ospf version 2 april 1998 interface the connection between a router and one of its attached networks. The book also briefly discusses two proprietary cisco protocols, intergateway. Ospf allows statespecific routing to take place, which leads to an environment where routing delays occur on a much less frequent basis. It is one among the 2 link state routing protocols. How to configure ospf routing protocol using packet tracer. Distance vector protocol link state protocol ospf operation.
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. The part of the ospf protocol used to establish and maintain neighboring relationships. Three typical types of routing protocol are chosen as the simulation samples. Home downloads download cisco ccnp routing pdf study guide. Abstract this memo documents version 2 of the ospf protocol. Nov 04, 2014 open shortest path first ospf is a standard routing protocol thats been used the world over for many years. The show ip protocols command, will show you the ospf process number and basic information about the. Eigrp has become a public routing protocol since 20. Overview in lab 6 we discussed rip, which is the canonical example of a routing protocol built on the distancevector algorithm. Troubleshooting of open shortest path first ospf routing protocol can be eased by using the most relevant options with the show command. By using these information sources you can gather the essential information to resolving your network problems. Ospf uses the dijkstra shortest path first algorithm to determine the shortest path. Troubleshooting open shortest path first ospf routing ip. Open shortest path first ospf is the first linkstate protocol that you will learn about.
Important ospf interview questions and answers with pdf to. Link state routing protocols advertise the state of their links. Troubleshooting your open shortest path first ospf routing protocol is eased by the show ip ospf command which provides information specifically addressed to this protocol. Protocol igp developed by the ospf working group of the internet engineering task force ietf. Frrs seamless integration with the native linuxunix ip networking stacks makes it applicable to a wide variety of use cases including connecting hostsvmscontainers to the network, advertising network services, lan switching and routing. You may have realized that you cannot run eigrp in a. Ospf routes packets based entirely on the destination ip of the. Verifying the ospf protocol techlibrary juniper networks.
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