„Software-defined Networking“ – Versionsunterschied

 

==Background==

Over the past decades Internet Protocol (IP) based networks used the notion of Autonomous Systems (AS) in order to scale and extend. Under this approach connected network junctions are able to forward datagram packets to a reasonable next hop based on partial need to know basis.

This is much like how the traditional post office service operates, where a postal worker in London does not need to know all the tenants of of all the streets in San Francisco in order to choose a reasonable next hop for a letter at hand. This approach to networking is simple, resileent, and it scales, but it has strong drawbacks. For one thing it does not allow the designated destinations, or tenants in the above analogy, to move without changing their identity as far as the packet delivery service is concerned. Their topological location, which is the network interface they are attached to defines their identity. In fact, using this traditional approach to internetworking, it is very hard to be specific regarding many other identity qualities such as logical grouping, access control, quality of service, intermediate network processing, etc.