Enterprise routers
There are also routers specific to enterprises such as access routers, distribution routers and core routers.Access Routers
Access routers are usually at the customer's end and this includes Small Office Small Home networks. Usually these routers don't need anything extra doing to them and just requires to be set up to the main network or the network in the branch.
Distribution Routers
Distribution routers do pretty much what its names suggests and distributes and collects traffic from multiple routers within the WAN. Often distribution routers can be used to ensure that quality is there throughout the network and as a result of that they need to have multiple WAN interfaces as well as a considerable amount of memory to be able to control traffic, collect information and ensure a quality service throughout the WAN.
Core routers
Core routers are basically used as the 'backbone' as it is known. They need to be able to forward packets to the other pieces of hardware that it is connected to at a high speed meaning that they need to be optimized for this sort of performance. It can also be used to connect the distribution routers in a large organisation.
Definition
Ultimately a router is a piece of hardware that links together two or more subnets which are basically a range of logical addresses within a given number/address range.
Types of routers
There are generally two main types of router, ones that allow for internet access and small office small home (SOHO) connectivity. The latter are basically used in homes and the such to connect computers to the internet on a broadband service using IP over either DSL or cable depending on the user's connection type.
Internet Access Routers
The routers that are used for internet access in general by ISPs where they are placed at the edge of the ISP's network (this type of router is known as a Provider Edge Router). Sometimes, though they are used to connect ISPs to other ISPs so that they can communicate (this is known as an Inter-provider Border Router).
Lastly these types of routers can be placed slap bang in the middle of an LAN to keep it going and essentially work as the 'internet backbone' as it has been dubbed over the years (this router is commonly referred to as a Core Router).