Routing in telephone networks distance vector routing link state routing choosing link costs hierarchical routing internet routing protocols routing within a broadcast lan multicast routing routing with policy constraints routing for mobile hosts. Difference between distance vector routing and link state routing. This chapter from ccna data center dcicn 640911 official cert guide introduces the concepts behind interior gateway protocols igps, typically used inside one company. On the other hand, link state routing protocols require more cpu power and memory than distance vector routing protocol algorithms. Routing algorithms distance vector, link state study notes. Distance vector protocols have slow convergence and suffer from the counttoinfinity problem details of which you can find here. Ospf is not a distancevector protocol like rip, but a linkstate protocol with a set of metrics that can be used to reflect much more about a network than just the number of routers encountered between source and destination. In ospf, a router attempts to route based on the state of the links.
In computer communication system which deals with packet switched networks a distancevector routing protocolripv2 and linkstate protocolospf are the two. Rip v1, rip v2, and igrp are distance vector protocols. Link state ls algorithm the link state ls algorithm assumes that one or more nodes in the network know the cost of each direct nodetonode link between neighboring nodes and, from this information, can construct the optimum routing tables for messages flowing through the network. Link state global view distance vector local view maintain sanity. Feb 15, 2016 link state routing protocols are the second type of routing protocols. Secondly routes learned from other neighbors are never passed on unless validated by igp rule of synchronization differentiating it from link state routing protocol. Link state protocols use a hierarchical structure that limits the distance that a linkstate advertisement lsa need to travel. Easy to get confused simple but limited, costly and slow 15 hops is all you get. What is the difference between link state routing and. Distance vector protocols date back to the arpanet network in the early 1970s. Link state and distance vector routing protocols it tips. Distance vector routing calculates the best route based on the distance fewest number of hops. When i explained about the fundamentals of link state routing, i purposefully chose not to discuss areas because they introduce the distance vector nature into the link state world and i thought it to be confusing, especially in a post that tries to draw a clear line between the distance vector and link state world.
Mar 01, 2018 the prior difference between distance vector routing and link state routing is that in distance vector routing the router share the knowledge of the entire autonomous system whereas in link state routing the router share the knowledge of only their neighbour routers in the autonomous system. Introduction to link state routing protocols what is. Performance analysis of distance vector and link state. Much like some complicated but capable distance vector routing protocols, link state routing protocols use a lot of calculation overhead when devising routing table topology changes and route updates. What is the difference between link state and distance vector. Linkstate routing protocols are one of the two main classes of routing protocols used in packet switching networks for computer communications, the other being distancevector routing protocols. The terms distance vector and link state are used to group routing protocols into two broad categories based on whether the routing protocol selects the best routing path based on a distance metric the distance and an interface the vector, or selects the best routing path by calculating the state of each link in a path and finding the path that has the lowest total metric to reach the destination. Distance vector assume each router knows its own address and cost to reach each of its directly connected neighbors bellmanford algorithm distributed route computation using only neighbors info mitigating loops split horizon and posion reverse cse 123 lecture. Distance vector and link state routing protocol ccna. Algorithms may be static, the routing decisions are made ahead of time, with information about the network topology and capacity, then loaded into the routers. Nov 17, 2017 link state routing protocol reduces the network data overhead, unlike distance vector routing protocol, by using partial computation when a link metrics changes in the network.
In a pure distance vector protocol, the only information that you have is a distance. The load on routers will be large however, since processing is complex. Link state routing protocol reduces the network data overhead, unlike distance vector routing protocol, by using partial computation when a link metrics changes in. By distributing the state of the links attached to the routers. On the contrary, in link state routing the router receive complete information on the network topology. Even neighbors need to manually configured unlike any distance vector or link state routing protocols. The term distance vector refers to the fact that the protocol manipulates. A pathvector routing protocol is a computer network routing protocol which maintains the path information that. When receiving a linkstate packet lsp, linkstate routing protocols immediately flood the lsp out all interfaces except for the interface from which the lsp was received. Apr 12, 2017 we consider bgp to be a path vector protocol. Walter goralski, in the illustrated network second edition, 2017. In particular, this chapter discusses the theory behind types of routing protocols, including distance vector and link state logic.
Sep 12, 2011 what is the difference between link state and distance vector. Link state when would you choose one over the other. Difference between linkstate and distance vector protocols. Link state routing protocols are a different breed and make of routing protocols as they go about the process in a remarkably different way. Routing in telephone networks distancevector routing linkstate routing choosing link costs hierarchical routing internet routing protocols routing within a broadcast lan multicast routing routing with policy constraints routing for mobile hosts. Easy to get confused simple but limited, costly and slow. Distance vector routing protocol computer networks youtube. The chapter also introduces the routing information protocol rip, enhanced interior gateway routing protocol eigrp, and open shortest path first ospf routing protocol. Lecture overview distance vector assume each router knows its own address and cost to reach each of its directly connected neighbors bellmanford algorithm distributed route computation using only neighbors info mitigating loops split horizon and posion reverse cse 123 lecture.
Dijkstras shortest path first algorithm link state. Distance vector, link state, and path vector introduction. Distance vector protocols are used in small networks, and it has a limited number of hops, whereas link state protocol can be used in larger networks, and it has unlimited number of hops. Examples of linkstate routing protocols include open shortest path first ospf and intermediate system to intermediate system isis the linkstate protocol is performed by every. Link state routing protocols are widely used in large networks due to their fast convergence and high reliability. Distance vector routing it is a dynamic routing algorithm in which each router computes distance between itself and each possible destination i. A router floods its link state to all other routers.
Must wait for eventual arrival of correct lsas to fix loop. Link state protocols use multicasts to share the routing information. Examples of link state routing protocols include open shortest path first ospf and intermediate system to intermediate system isis. Understanding the ospf linkstate routing protocol ipv4. They have the same basic purpose as distance vector protocols, to find a best path to a destination, but use different methods to do so. Compared to link state protocols, which require a router to inform all the nodes in a network of topology changes, distance vector routing protocols have less computational complexity and message overhead. Link state and distance vector protocols uses different algorithms. What is the difference between distance vector protocol. Advanced distance vector advanced distance vector is the title cisco gives to eigrp, which borrows the best attributes of both distance vector and link state designs. Unlike distance vector protocols, link state protocols dont advertise the entire routing table.
Distance vector algorithms being simpler require simpler hardware. Link state routing protocol an overview sciencedirect topics. Linkstate ls algorithm the linkstate ls algorithm assumes that one or more nodes in the network know the cost of each direct nodetonode link between neighboring nodes and, from this information, can construct the optimum routing tables for messages flowing through the network. When i explained about the fundamentals of linkstate routing, i purposefully chose not to discuss areas because they introduce the distancevector nature into the linkstate world and i thought it to be confusing, especially in a post that tries to draw a clear line. Distancevector routing protocols use the bellmanford algorithm and fordfulkerson algorithm to calculate the best route. Link state routing link state routing is the second family of routing protocols.
One problem with distancevector routing is that it can send traffic to slower links which have less hops than faster links which have more hops, whereas linkstate routing doesnt care about the number of hops, only the cost, to get to the destination network. But in link state, routing protocols updates the network only when a change in network happens, and it is created to overcome the drawbacks of distance vector protocol. Counttoinfinity with distance vector routing, good news travels fast, but bad. In particular, this chapter discusses the theory behind types of routing protocols, including distance vector and linkstate logic.
Link state routing protocol an overview sciencedirect. Algorithms may be dynamic, where the routers make decisions based on information they gather, and the routes change over time, adaptively. Link state protocols send information about directly connected links to all the routers in the network. Goals for todays lecture learning about routing protocols link state global view distance vector local view maintain sanity. Distance vector protocol an overview sciencedirect topics. Distance vector routing protocols are less scalable such as rip supports 16 hop. It is a point to point communication between sender and receiver. One problem with distance vector routing is that it can send traffic to slower links which have less hops than faster links which have more hops, whereas link state routing doesnt care about the number of hops, only the cost, to get to the destination network. There are two major differences between distance vector routing protocols and link state routing protocols. Distance vector routing protocol computer networks. Each router uses these parameters to compute the resulting distance to a destination.
With distance vector routing algorithm, router needs to process each routing update and update its routing table. Link state routing protocols are one of the two main classes of routing protocols used in packet switching networks for computer communications, the other being distance vector routing protocols. Much like some complicated but capable distancevector routing protocols, link state routing protocols use a lot of calculation overhead when devising routing table topology changes and route updates. Shortestpath link state routing flood link weights throughout the network compute shortest paths as a sum of link weights forward packets on next hop in the shortest path convergence process changing from one topology to another transient periods of inconsistency across routers summary. Linkstate and distance vector routing examples iwan syarif. With bgp, you have both a distance, plus the best path to the destination. How is bgp different from linkstate and distancevector. These paper includes the differences between various link state and distance vector routing protocols. In this video, russ goes through the differences between a distance vector and link state routing protocol. It is a dynamic routing algorithm in which each router computes distance between itself and each possible destination i.
Routing algorithms distance vector, link state study. Performance analysis between distance vector algorithm dva. In distance vector routing the routers receive the topological information from the neighbour point of view. If the network is stable, link state protocol refloods each lsa regularly, ex. Difference between link state and distance vector compare.
Distance vector means that routers are advertised as vector of distance and direction. Ospf is not a distance vector protocol like rip, but a link state protocol with a set of metrics that can be used to reflect much more about a network than just the number of routers encountered between source and destination. Distancevector routing protocol 1 distancevector routing protocol in computer communication theory relating to packetswitched networks, a distancevector routing protocol is one of the two major classes of routing protocols, the other major class being the linkstate protocol. Distance vector distance vector routing protocols are based on bellma and ford algorithms. The simulation of linkstate routing protocol is a part of the project under course cs542 computer networks. Distance vector exchanges the routing updates periodically whether the topology is change or not, this will maximize the convergence time which increases the chance of routing loops while the link state routing protocols send triggered change based updates when there is a topology change. This paper compares the performance of all the distance vector and link state routing protocols with both ipv4 and ipv6 with default parameters.
Contrast with link state protocol and path vector protocol. Link state routing protocols are the second type of routing protocols. Describe the distance vector routing protocol with examples. Learn which type of routing protocol could work best in your environment. Section linkstate versus distance vector in the chapter routing basics in the cisco. The router share its knowledge about the whole network to its neighbors and accordingly updates table. All routers in area 0 can now compute their distance to n1 and n2, using their distances to x4 and x6, and using the principle of distance vector item 1 of the principle. State the major difference between distance vector routing and link state routing. Difference between distance vector routing and link state. The prior difference between distance vector routing and link state routing is that in distance vector routing the router share the knowledge of the entire autonomous system whereas in link state routing the router share the knowledge of only their neighbour routers in the autonomous system. Another way of calculating the best route across a network is based on link cost, and is implemented through linkstate routing protocols.
Because of their awareness of media types and other factors, link state protocols require more processing power more circuit logic in the case of asics and memory. Assume each router knows its own address and cost to reach each of its directly connected neighbors. The cost for a path to a network is the aggregated costs for each link in the path. A linkstate routing algorithm dijkstras algorithm net topology, link costs known to all nodes accomplished via link state broadcast.
Find out inside pcmags comprehensive tech and computerrelated encyclopedia. The 2 major quality of a distance vector protocol is that it will send the updates periodically and its update would contain information only about directly connected neighbors whereas link state protocol sends information of all the known routes and does send it nonperiodically triggered update. Dijkstras algorithm topology and link costs known to all nodes accomplished via link state broadcast all nodes have same. The other differences of both types of routing protocols are as follows. Recall example from distance vector routing where network partitions. In this work the technique has selected two proactive, tables driven routing protocols from distance vector routing dvr and link state. The program accepts the network topology details in terms of the cost of links, and provides the shortest path tree for the network. The router share its knowledge about the whole network to its neighbors and accordingly updates table based on its neighbors. A distancevector routing protocol in data networks determines the best route for data packets. While distance vector routers use a distributed algorithm to compute their routing tables, linkstate routing uses linkstate routers to exchange messages that allow each router to learn the entire network topology.
407 1098 1427 462 980 859 219 821 1604 210 288 57 1506 1342 287 53 1472 44 59 558 1523 1101 395 474 278 132 713 504 170 1024 1083