Our world is generating data at a speed faster than ever before. In year 2010, 5 Exabytes (1018 bytes, or 1 billion Gigabytes) of data were created every two days, which exceed the total amount of information that was created by human beings from the dawn of civilization to year 2003.1 Till 2020, over 40 Zettabytes (1021 bytes) of data would be created, replicated, and consumed.2 With the overwhelming amount of data pouring into our lives, from anywhere, anytime, and any device, we are undoubtedly entering the era of Big Data.
When a device has multiple paths to reach a destination, it always selects one path by preferring it over others. This selection process is termed as Routing. Routing is done by special network devices called routers or it can be done by means of software processes.The software based routers have limited functionality and limited scope.
A router is always configured with some default route. A default route tells the router where to forward a packet if there is no route found for specific destination. In case there are multiple path existing to reach the same destination, router can make decision based on the following information:
- Hop Count
Routes can be statically configured or dynamically learnt. One route can be configured to be preferred over others.
A. Unicast Routing
Most of the traffic on the internet and intranets known as unicast data or unicast traffic is sent with specified destination. Routing unicast data over the internet is called unicast routing. It is the simplest form of routing because the destination is already known. Hence the router just has to look up the routing table and forward the packet to next hop.
Picture 1 : Unicast Routing