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Routing and Switching Selection Criteria.  Please respond to the following:

• Compare and contrast distance-vector and link state routing, and analyze the limitations that would prevent the usage of each.
• Choose the method best suited for designing a new routing protocol for a LAN architecture. Justify your decision

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COLLAPSE

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Compare and contrast distant-vector and link state routing, and analyze the limitations that would prevent the usage of each.

In distance-vector routing, all routers pass a copy of the routing table to its neighbors. The routers also maintain a table of minimum distances to every node. The neighbor adds the route to its own table, incrementing the metric to reflect the extra distance to the end of the network. The distance is given as a hop count; the vector part specifies the address of the next hop. When a router has two routes to the same network, it  chooses the one with the lowest metric, taking for granted that it is faster to route through fewer hops. Routing Information Protocol (RIP) implements distance-vector routing.

Link state routing floods routing information to all routers within a network. It  tries to build and maintain a more complicated route database with more information about the network. Routers can exchange information about a route, such as the quality, bandwidth, and availability of the route. Because of this, the routers can make a decision about whether to send data through the network based on more information rather than just the hop count. Link state algorithms broadcast small updates and converge quickly, a feature that makes them less prone to routing loops. However, link state algorithms are more expensive to put into place because they require more power and memory. The Open Shortest Path First (OSPF) protocol implements link state routing.

Choose the method best suited for designing a new routing protocol for a LAN architecture. Justify your decision.

Distance-vector prefers dial-up based on the hop count alone; link-state prefers the two hop route through a higher bandwidth connection. Also, link state is more complicated to set up and maintain than distance-vector. An administrator will have to configure more information about the routers' local routes. However, link state routers are a necessity in situations with multiple routes through different types of connections, such as border routers.

Reference:

Chwan-Hwa, W. Irwin, D. (2013) Introduction to Computer Networks. Boca Raton, FL. Taylor and Francis Group