Open Shortest Path First and Routing Information Protocol - Research Paper Example

Open Shortest Path First (OSPF) compared to Routing Internet Protocol (RIP) due: Open Shortest Path First (OSPF) and Routing Information Protocol (RIP) In computer networking, there are various techniques used. This includes but not limited to, open shortest path first (OSPF) as well as routing internet protocol (RIP). The protocols makeup an all rounded, complete, wireless network. The two protocols form the main algorithms for routing. Each of the protocols has its own benefits and drawbacks. Routing is the process of selecting a path through which to send data in network traffic. Routing can be applied in various ways such as internet protocols, for sending packet data or even in telephones. The OSPF and the RIP are some of the algorithms used in the routing process (Dubey, Makloha, & Sarwar, 2012). Each of the algorithms is discussed in this paper, in an attempt to bring out their operations and effectiveness in terms of transmission of the packet data, in an electronic data transfer (Sendra, Fernández, Quilez, & Lloret, 2011) Open shortest path first (OSPF) This is the most widely used protocol due to its dynamism in the transfer of electronic data that is in the internet protocol networks. It is categorized in the interior gateway protocols. It is highly preferred due to its low cost of the links to a destination in terms of calculating the optimal routes, based on Dijikstar’s algorithm (Sendra et al., 2011). The working of the OSPF protocol will be discussed in the following perspectives: 1. Metrics A router measures the cost involved for it to communicate with its neighbors. This cost is used to determine the best route to take. The formula for calculating the cost is given by: Cost= 10000 0000 /bandwidth in bps When the bandwidth is wider, the cost is lower; the interface with the lowest cost will be chosen to send data (Wang, Hoque, Alyyan, & Zhang, 2012) 2. Types of messages A router will send packets to its neighborhood routers so as to trace their positions and status. These packets are referred to as hello packets since they are sent to check how the neighboring routers are doing. For OSPF routers, they have both hello and dead time intervals being exchanged. Various manufacturers of the routers have designed them differently such that, there is a set number hello messages sent to the router, after which if it doesn’t respond, it is considered dead (Kamalakannan, Venkatesh, & Mohan, 2014). In an OSPF topology, the network is divided into areas and uses link state packets (LSP) to update each of its surrounding routers with the corresponding cost. OSPF has high scalability due to its ability to send seven different messages which are used to identify the proximity to the neighbors and also exchange information with the neighbors (Thorenoor, 2010). 3. Algorithm operation OSPF routers choose a designated router and a backup designated router which are used as the central points for updating the routers and exchanging the routing information. To avoid deadlocks when the OSPF priorities are the same, the router ID takes the designated router (DR) election. The link state information is then sent by DR to all other OSPF routers in the same segment via the multicast address 224.0.0.5.The advantage with this is that there is higher efficiency than when there is no DR, but the disadvantage is that there is now a single point of failure (Sendra et al., 2011). 4. Node status When there are topology changes, routing produces a large volume of traffic. OSPF supports variable-length subnet mask (VLSM) and multiple routes thus maximizing its addressing efficiency. Router Information Protocol (RIP) Being the oldest routing protocol, it has evolved into two versions; RIPv1 and RIPv2.The former was seen as obsolete prompting the need for development of the latter version to cope with the current demands in the networking area.RIPv2, which is the latest version, is a classless protocol. This protocol will be discussed based on the following perspectives. 1. Metrics It counts the number of routers a message will hop before reaching its destination. All routes with distance greater than 15 are considered unreachable since the maximum number of hops it can make is 15. 2. Message types After every 30 seconds, RIP sends messages. This is a major shortcoming of this protocol, simply because it has to keep on updating the database which generates a large amount of traffic on the network. The improvement of RIPv2 allows it to use Classless Inter-Domain Routing (CIDR), something which RIPv1 couldn’t do. The addition of the subnet mask allows it to add a 32-bit mask. The utilization of the multicast address 224.0.0.9 is an advantage of RIPv2, since it allows it to consume less network bandwidth. 3. Tables Routing databases must be constantly updated to assign the most suitable routes to the routers. Without such updates, a router might end up being assigned a route which no longer exists. The databases provide information about the cost of each route as well as the next hop to be taken to reach the next destination (Dubey et al., 2012) 4. Algorithm operation RIP routers operate in such a way that, they only maintain the best route to a destination. However, if the cost for a given route is the same, then they can keep more than one route to the same destination. The main shortcoming with this algorithm is that it takes too much time to converge which could result to inconsistent routing entries causing rooting loops (Wang et al., 2014). Comparison between RIP and OSPF in terms of performance From the above discussion on the working of the two protocols, it is clear that both have their own pros and drawbacks. However, OSPF has wide applications as described by Kamalakannan et al. (2014) making it the most widely used protocol especially in the large enterprises in networks (p. 4). One of the advantages of using this protocol is it is based on link-state technology which uses SPF algorithm to calculate the shortest path possible, as researched by (Kamalakannan et al., 2014). It ascertains that all the routers in the network get to know about all the other routers in the same network just before it runs the calculation. After that, the shortest path between each router is calculated. When a router receives a link-state update, the information is kept into the database, and the router propagates the updated information to the rest of the routers. On this regard, it is clear that there are no limitations due to hops in OSPF, unlike in RIP which has a limitation of 15 hops, meaning when the 15 hops are exceeded the network cannot be reached. Also, OSPF can handle VLSM but RIP cannot (Kamalakannan et al., 2014). What makes OSPF protocol better than RIP? OSPF proves to be far much better than the rip due to its ability to converge the network paths using the shortest path first (SPF) algorithm and error detection. This is made possible by its features discussed below which makes it adapt quickly to topology changes: It achieves this by using the mechanisms of the interface status changes and the failure to receive hello packets from its neighbors through the dead timer timing window. After the expiry of the timer, the neighbor is assumed to be dead. To configure the dead timer, an interface configuration command called IP OSPF dead-interval is used (Kamalakannan et al., 2014). In the rapid recalculation of a route mechanism, LSA packets are sent to all the neighboring routes after detection of a failure. This information is sent by the router which detected the problem to all the other routers directly connected to it, so that the change can be effected in all the routes so as to provide the shortest route. The ability of the OSPF to load balances along equal paths makes it achieve an almost immediate convergence (Wang et al, 2012). Conclusion From the discussion above, it is without doubt that OSPF is better than RIP in that it is not limited to hops, like the RIP whose limitation is 15 hops. OSPF also has the ability to handle Variable-Length Subnet Mask (VLSM) unlike RIP which cannot. Of importance to note is that OSPF converges much faster in comparison to RIP, made possible by its calculation algorithm. This has a lot of significances especially in the large enterprises networks. References Dubey, A., Makloha, S., & Sarwar, S. (2012). Implementation, Analysis & Comparision Of Routing Protocol (RIP & OSPF) Using Network Simulator Education Version OPNET. International Journal of Research in Engineering and Applied Sciences, 2(2), 633-640. Kamalakannan, S., Venkatesh, S., & Mohan, M. (2014). Convergence Analysis Of RIP And OSPF In IPv6 Network. Convergence, 2(3). Sendra, S., Fernández, P. A., Quilez, M. A., & Lloret, J. (2011). Study and performance of interior gateway IP routing protocols. Network Protocols and Algorithms, 2(4), 88-117. Thorenoor, S. G. (2010, April). Dynamic routing protocol implementation decision between EIGRP, OSPF and RIP based on technical background using OPNET modeler. In Computer and Network Technology (ICCNT), 2010 Second International Conference on (pp. 191-195). IEEE. Wang, L., Hoque, A. K. M. M., Yi, C., Alyyan, A., & Zhang, B. (2012). OSPFN: An OSPF based routing protocol for Named Data Networking. University of Memphis and University of Arizona, Tech. Rep. Read More