This paper examines how ospf works and how it can be used to design and build large and complicated networks. Open shortest path first ospf routing protocol dummies. Now, it is time to move on to the infamous debug commands that are available to open shortest path first ospf routing protocol. Its newest implementation, version 2, which is explained in rfc 2328, is an open standard. If two or more of these routes have equal metrics, load balancing across them may occur. Define area 9 as a totally stubby area area 9 stub nosummary. Introduction this document is a specification of the open shortest path first ospf tcpip internet routing protocol.
In figure 320, the ospf routing protocol has been enabled on all routers and the network has converged. Metric in the event there are multiple routes learned by the same protocol with same prefix length, the route with the lowest metric is preferred. Open shortest path first open shortest path first ospf is an openstandard link state 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. As you said that both vrfs having the same subnet then the required solution will not possible due to routing protocol behavior. Upon completion of this course, you will be prepared for the cisco certified network professional ccnp routing and switching certification exams 300101 route, 300115 switch, and 3005. Open shortest path first ospf is a routing protocol for internet protocol ip networks. Ip address configured with the ospf routerid command.
The ospf mib defines an ip routing protocol that provides management information related to ospf and is supported by cisco routers. 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. Routing protocol is ospf 1 outgoing update filter list for all interfaces is not set. Routing protocol packets are sent with type of service tos of 0. Introduction to isis isis is an igp, linkstate routing protocol, similar to ospf. 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. Home downloads download cisco ccnp routing pdf study guide. Therefore, when the packet arrives on r1, the best route to reach the pc2 network would be to send it to r3, which would then forward it to r2. Ospf routing protocol cisco networking, vpn security.
Ospf configuration step by step guide this tutorial explains how to configure ospf routing protocol step by step with practical example in packet tracer. This section covers ospf in great depth from ccna to ccnp level. In general, the operations of a dynamic routing protocol can be. Open shortest path first, or ospf, is a routing protocol thats based on open standards, meaning any vendor can implement its features.
Ospf adheres to the following link state characteristics. 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. How to configure ospf routing protocol using cisco packet. Ospf is a standardized linkstate routing protocol, designed to scale efficiently to support larger. In general, the operations of a dynamic routing protocol can be described as follows. Give c second priority bdr in election ip ospf priority 50 interface loopback0 ip address 10. Ospf will form neighbor relationships with adjacent routers in the same area. Debugging open shortest path first ospf routing protocol. The ospf router id is used to uniquely identify the router in the ospf routing domain. Routers that act as gateways redistributionbetween ospf and other routing protocols igrp, eigrp, isis, rip, bgp, static or other instances.
Our articles contain detailed information, network diagrams and illustrations to ensure the reader can easily understand all covered topics and presented information. The following example shows how to start the spf algorithm without first clearing the ospf database. The working group was formed in 1988 to design an igp based on the. Open shortest path first ospf is an active routing protocol used in internet protocol. How to configure ospf routing protocol using cisco packet tracer. The open shortest path first ospf protocol is a link state protocol that handles routing for ip traffic. This paper examines how ospf works and how it can be used to design and build large and. Ospf version 2 is documented in rfc 1583 a lengthy document that i find very difficult to read. The book also briefly discusses two proprietary cisco protocols, intergateway. 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. This means that it distributes routing information between routers belonging to a single autonomous system. 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. Sanctioned by the ietf, it is intended to become internets preferred interior routing protocol. Ospf makes a routing protocol decision based on the best bandwidth.
Mib defines an ip routing protocol that provides management information related to ospf and is supported by cisco routers. Open shortest path first ospf is a one of the famous routing protocol, it is a very vast topic and this ospf quiz is covering the most important questions related to ospf, that may be ask from you in networking interview. For protocolindependent features that work with ospf, see the configuring ip routing protocolindependent features module. You can retake the quiz for randomly selected new questions. The working group was formed in 1988 to design an igp based on the shortest path first spf algorithm for use in the internet. 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.
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. In this article we will learn about the ospf routing protocol. Open shortest path first ospf is an open standard not proprietary and it. Open shortest path first ospf is an openstandard link state routing protocol. You can set different process id from 165535 for each router. A concrete understanding of how ospf routing works is fundamental for any small or large network. Open shortest path first ospf is a dynamic, hierarchical routing protocol designed to support routing in tcpip networks. Ospf general uses il spf algorithm link state routing protocol classless routing protocol open and standard protocol ospfv2 cheat sheet ospf tables neighbor table topology table routing table ospf network types broadcast cisco nbma nonbroadcast multi access point to point cisco point to multipoint.
Particularly it is a link state routing protocol and includes into the group of interior gateway protocol. Eigrp has become a public routing protocol since 20. Protocol and port udp port 520 ip protocol 9 ip protocol 88 ip protocol 89 tcp port 179 routing protocol comparison routing protocol comparison v1. Ospf open shortest path first 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. As with the show command, the debug command has many options. Ospf is commonly used in large service provider networks or large financial institutions. Understanding basic open shortest path first ospf routing principles not only applies to the ccnp certification but to all ciscobased certifications.
Jul 26, 2017 open shortest path first, or ospf, is a routing protocol thats based on open standards, meaning any vendor can implement its features. Using live labs allow you to develop your practical it skills in a safe working environment without the need to invest in your own hardware and software. Open shortest path first ospf is a recent entry into the internet interior routing scene. Because spreading the net too widely can cause a lot of information to sift through, you want to make the scope of the command as narrow as possible.
The ospf protocol is a linkstate routing protocol, which means that the routers exchange. Ospf is a linkstate routing protocol with a complex set of. Three typical types of routing protocol are chosen as the simulation samples. Cisco is an active member of the ospf working group at the ietf, and is responsible for many of the ongoing enhancements to. Introduction to open shortest path first ospf protocol. For years cisco, juniper, and other major networking vendors. The purpose of routing protocols is to learn of available routes that exist on the enterprise network, build routing tables and make routing decisions.
The specific operations of rip, eigrp, and ospf are examined in later chapters. Like all linkstate protocols, ospf is very efficient in its use of network bandwidth. Unlike routing information protocol rip, ospf does not provide periodic routing updates. Comparison of rip, ospf and eigrp routing protocols based on. Rip routing information protocol is one of the oldest routing protocols still in service. Cisco is an active member of the ospf working group at the ietf, and is responsible for many of the ongoing enhancements to the protocol. Some of the most common routing protocols include rip, igrp, eigrp, ospf, isis and bgp. 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. A simulation of the ospf election protocol shows three results.
Pdf open shortest path first ospf routing protocol. Open shortest path first ospf operating inside a distinct autonomous system. View a summary of the ospf linkstate database entries from the command dropdown located in the right pane, select ospf database summary. This tutorial explains how to configure ospf routing protocol step by step with practical example in packet tracer. To configure ospf on a router, there are two steps. The version 2 of open shortest path first ospf defined in 1998 for.
The routing management protocol rmp based on the open shortest path first ospf algorithm provides routing of data units within the lec network and to external networks. Comparison of rip, ospf and eigrp routing protocols based. It forms neighbor adjacencies, has areas, exchanges linkstate packets, builds a linkstate database and runs the dijkstra spf algorithm to find the best path to each destination, which is installed in the routing table. Understanding basic open shortest path first ospf routing principles not only applies to the ccnp certification but to all cisco based certifications. 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. Cisco routers derive the router id in one of three ways and with the following precedence. Cisco ios xr routing configuration guide for the cisco crs router, release 4. It uses a link state routing lsr algorithm and falls into the group of interior gateway protocols igps. Ospf employs a hierarchical network design using areas. Link state routing protocols advertise the state of their links. 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. Ccna training comprehensive guide on ospf routing protocol. As it is a vrf lite then you can redistribute leak ospf routing protocol database between vrfs but you have to use the bgp routing protocol for making it possible. By collecting connectivity information from all of the devices on the network, ospf.
Ospf is developed by internet engineering task force ietf as one of the interior gateway protocol igp, i. Ospf is a linkstate routing protocol providing fast convergence and excellent scalability. Intraarea o interarea o ia external type 1 e1 external type 2 e2 nssa. Hop count is the metric that rip uses and the hop limit limits the network size that rip can support. Cisco routers derive the router id in one of three ways and with the following. Open shortest path first ospf is a linkstate routing protocol that is used to find the best path between the source and the destination router using its own shortest path first. Optional md5 authentication configured ip ospf authentication messagedigest ip ospf messagedigestkey 1 md5 foobar. The operations of a dynamic routing protocol vary depending on the type of routing protocol and the specific operations of that routing protocol. Ospf lsa manipulation vulnerability in multiple cisco products.
In this lesson ill explain the basics of ospf to you and you will learn how and why it works. Ospf is classified as an interior gateway protocol igp. Open shortest path first ospf is a routing protocol developed for internet protocol ip networks by the interior gateway protocol igp working group of the internet engineering task force ietf. Bgp pdf created with fineprint pdffactory pro trial version. Network routing protocols igrp, eigrp, ospf, isis, bgp. 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. Therefore, when the packet arrives on r1, the best route to reach the pc2 network would be to.
Multiple cisco products are affected by a vulnerability involving the open shortest path first ospf routing protocol link state advertisement lsa database. Gateway routing protocol eigrp is an example of a balanced hybrid routing protocol. Ospf general uses il spf algorithm link state routing protocol classless routing protocol open and standard protocol ospfv2 cheat sheet ospf tables neighbor table topology table routing table ospf network types broadcast cisco nbma nonbroadcast multi access point to point cisco point to. Mar 26, 2017 open shortest path first ospf is a routing protocol for internet protocol ip networks. 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. One of the most popular dynamic routing protocols available is the open shortest path first ospf. On becoming neighbors, ospf routers establish an adjacency by. 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 ospf is a linkstate routing protocol, rather than a distance vector protocol.