Routers: supercomputers of Internet

Guide the information to its destiny by the fastest way, has a computational cost so high, because have to consider various factors as the saturation, the speed of the lines, etc. If in addition the router must filter, prioritize or inclusive transform the information, the cost increase further more. Is needed specific hardware to do this task with a high and constant performance, but, if we use as router a personal computer will have a worst performance because it's hardware of general purpose.

The routers are organized hierarchically. As more go up in the hierarchy, more performance have, more data move and more expensive are.

In first place are the routers that all we have in our house. These usually have only two ports, one for Internet and another that connects internally with a switch or hub, that carry the information by several cables to the devices of our house. These usually are cheaper, some are so bad, and when have to route a lot of traffic they overheats and stop. After, the information is passed through some routers of the internal network of our Internet service provider that can be organized by zones. Following, we have the router that includes the network of the Internet provider and this can go to another router or be connected directly to one of the edge routers that pass the information to a core router or backbone router, the highest of the hierarchy, that have a monstrous hardware in number of processors and memory, and can cost thousands of dollars. Its funding is made by governments, universities and big enterprises.

The routers have been very important since the beginning of Internet. In 1969, a core router could have 6 links of 56 Kbit/s. The needs of speed of transference have been increasing with the time and now a core router moves hundreds of Tbits/s. These, also use a special protocol, the Border Gateway Protocol (BGP), to route the bigger quantity of information to the routers in the less time possible.

The principal manufactures of core routers are Cisco Systems and Juniper Networks. In the next photo you can see a model of Cisco:

This is the Cisco CRS 3 it cost is about $ 90.0000 and with a transfer speed of 322 Tbits/s can transfer in streaming all the movies made since now in only four minutes.

At last a world map with the density of routers (up), compared to the density of population in the world (down):

So now you know that if you want shutdown Internet in a country you only have to destroy its core routers.