Describe methods of routing traffic on a network
Routing
Routing is the process of determining a path for a packet to take towards a destination.
Routers contain a routing table of all the networks they are connected to.
Routing protocols calculate the optimum path based on various metrics. The most simple is RIP (routing information protocol) which uses the total hop count, where the lowest hop count has the lowest ‘cost’ and thus is the fastest.
Another routing protocol is OSPF (open shortest path first), which uses includes metrics like bandwidth, reliability and round trip time.
Static and Dynamic Routing
With static routing, the routing table is small and only contains one entry for each destination. Static routes are preconfigured.
Dynamic routing keeps a much larger routing table with a variety of routes to each destination. The routes that packets take would be different depending on changes in network conditions, like congestion and the addition/removal of nodes.
Calculate data transfer rates on a network
Bandwidth measures how much data can be fitted onto a cable at a time.
Bit rate expresses bandwidth and is used to describe a software’s data transfer requirements.
Bandwidth and bit rate are technically NOT speed. The speed is determined by the speed at which data can be physically transferred along the cables/through the air. Bandwidth and bit rate could lead to a faster transfer speed, like how adding more lanes to a motorway can let cars through at a faster rate even if the cars are travelling at the same speed as before.
Calculate lowest cost routes on a network
Costs can be calculated for each hop across a network using a variety of different algorithms, like RIP or OSPF.
In this example, costs have been calculated between nodes A-E. If A were to send a message to B, the fastest path would be A-C-B as it has the lowest cost of 5.