Hierarchical Routing

Why
Hierarchical routing is important because it allows us to maintain more nodes in our network in a manageable way

What
Hierarchical routing is the practice of grouping nodes in our network together and having a common way of referring to them. They can be seen as a supernode. Then, once the packets are passed into the supernode, the underlying routing algorithm of the supernode takes over and directs the packet to the correct host

Scalability
Having networks of networks is much more scaleable, as each router does not have to maintain information about every single other node in the network. This would take huge amounts of memory and updating the routing tables would be an impossible prospect

Administrative Autonomy
Companies who use networks want to be able to maintain them separately and privately

Autonomous Systems
To achieve hierarchical routing, we must organize our routers into autonomous systems. We must also designate specific routers in our system to deliever traffic in and out of our system. We call these routers gateway routers