Assignment 4,3 - AndrewWhittle/Net-215 GitHub Wiki

  1. The job of any routing protocol is to provide a mechanism for exchanging information about routes so routers can keep their routing tables up-to-date. Describe in your own words (a few sentences and/or detailed bullet points) the mechanism RIP uses so that routers in a network can build their routing table. (2 Points): Every 30 seconds, routers broadcast their routing table to other routers in the network so that all routers can have the same complete routing table.
  2. Describe in your own words, how RIP uses the Route Distance Metric (1 Point): In the case of RIP, the route distance metric comes in the form of hops. Each time the packet passes through a router, it is counted as one hop. RIP attempts to find the least number of hops in order to find the most efficient route.
  3. Describe in your own words (a few sentences or detailed bullet points) the limitations of RIP on a larger network (2 Points): Because the routers broadcast frequently, it can create a lot of extra traffic that can slow down larger networks. On top of this RIP has a max hop count of 15 which makes it unusable on larger networks.

OSPF is a very popular interior routing protocol and is widely used in larger enterprises.

  1. Describe in your own words (a few sentences and/or detailed bullet points) the mechanism OSPF uses so that routers in a network can build their routing table and how it differs from RIP v2. (2 Points): OSPF acts similarly by relaying information to its neighboring routers but OSPF does this through topologies. From there each router makes its own routing table using an algorithm.
  2. Describe in your own words, how OSPF uses the "Cost" Metric (1 Point): The cost metric is calculated by using the network's bandwidth, fast bandwidth means lower metric cost.

The next questions are based on the following router network. Each interface includes a network address and cost

  1. RIP is a vector distance router protocol. It considers the number of hops to reach a destination and picks the shortest one. Based on hop count. What is the shortest path between the client computer in the lower left and the server in Burlington, Vt and the number of hops. (1 Point): The shortest path is San Francisco to Seattle to Chicago to Boston to Burlington for a total of 5 hops.

  2. OSPF is a cost-based protocol and determines the path with the least cost. Based on cost, find the lowest cost path between the client computer in the lower left and the server in Burlington, Vt. and what is the total cost of the route? (1 Point): The lowest cost route is San Francisco to Denver(25) to Kansas City(10) to New York(10) to Boston(10) to Burlington(50). In total the cost would be 105.

Sources: