Routing is a process of maintaining routing tables. It is a procedure to transfer information from source to destination by choosing the most suitable/shortest path. Each router maintains its table containing information about the routes. The main components of the table are Destination, Distance of the link, next-hop count.
Basic Structure of Routing table
Whenever a packet arrives at the router/node, its destination is checked and the packet is attempted to be sent to the next-hop destination. To share the path information, these tables are frequently exchanged among its neighbors. Routers, in order to decide the best path between source and destination, uses some protocols. Routing algorithms, on the other hand, make use of certain metrics to decide the path. Each router may or may not know the shortest path to reach its destination but at least they know a way to get to the shortest path. Metrics are often denoted as the standard of measurement. To calculate the most optimal path, the metrics used are:
- Path Length
- Hop Count
Path Length: With each network link, some costs are associated. The path length is the sum of costs achieved while traversing through each link.
Bandwidth: Bandwidth refers to the data that can be transferred through network path or network length.
Hop count: The number of passes through routers etc. that a packet passes in a route from source to destination.
Load: The degree to which a network resource such as a router etc. is busy is known as a load. It can be calculated in terms of CPU utilization and processed packets.
Delay: The time required by a packet to reach from source to destination is known as Delay. The delay of packets often depends on network traffic, physical distance, bandwidth, etc.
Routing table determines the shortest route where each packet in a network will be determined.
Some important metrics are: Path length, bandwidth, hop count, load and delay.
Routing is a procedure of finding the most optimal path for a packet to be sent from sender to the receiver in a network