How the Internet works

From its inception in the late 1960s, the Internet has grown from a handful of host or server computers to millions of computer spread out like a wild fire across the whole globe know as “planet earth”. 

From its inception in the late 1960s, the Internet has grown from a handful of host or server computers to millions of computer spread out like a wild fire across the whole globe know as “planet earth”. 

These computers mentioned above lie on several networks, it is the collection or rather the interconnection of these numerous networks that gives rise to a one “worldwide” network.  As the Internet is sometimes described, the World Wide Web (www) is a descriptive definition of the Internet.

Just imagine a spider making a web, if one employed so many spiders, say a million of them, they are likely to make such a web that it would cover thousands of kilometres put together. 

The spiders’ web is woven from the centre going outwards and in a circular manner, this spreads it outwards at equal intervals. 

Let’s further assume that a spider on one point of the web wanted to have a message conveyed to its mother or father or auntie located several kilometres away, all it has to do is know exactly where the relative is and chart out a route from its location to the destination. 

Of course, it will have to relay the message out by either moving or yelling out the message to the nearest spider and that in turn does likewise to the next one and so on and so forth until the message is finally delivered.

The above is a mere hypothesis used to build the internet theorem. Back to the Internet topic, this collection of a very big multitude of networks of computers. 

These networks are interconnected in such a way that, each and every one is interconnected to one another.  For simplicity’s sake, we can compare “the Net” (as it is sometimes abbreviated) to a massive Electricity grid on which are several electricity producers as well as consumers. 

Some of the consumers are producers as well. The only difference is that, where as the power grid is owned by individual companies, the Net has no owners, it is like a co-operative society (ISOC) of all users and contributors alike; this doesn’t mean it is not monitored and maintained in different ways.

The Internet Society, a non-profit group established in 1992, oversees the formation of the policies and protocols that define how we use and interact with the Internet.  We can say that, ISOC is an internet watch dog. 

That said, the net is made up domain name servers (DNS), network access points and backbones comprising of several Internet Service providers (ISP). 

The whole scenario is more or less like this, you connect to the net through you personal computer (PC), this connects to the net via an ISP, in between your PC and the ISP, there is communication link e.g.

Modem (EVDO, GPRS, VSAT, FBRE), when you and your friends connect to a local ISP e.g. RWANDATEL, you become part of that Network. 

Several ISPs have their networks of computers.  For hypothetical purposes, let’s assume that, there are only three ISPs in Rwanda, viz, RWANDATEL, MTN and ARTEL (no malice intended), if these three ISPs’ networks have servers that host interactive materials, the members of one network can be able to communicate together within their own network. 

Each of these networks has its own identity and all computers on it may communicate along the same protocol because they lie along the same server. This is evidenced by the use of IP (Internet Protocol) addresses. 

IP addresses are numeric digits that are used to address each computer on any given network.  This address is used to identify every computer on the network; there are no two computers with the same IP on one network.

Because these numbers may look confusing to identify one computer from another, the architects of networking decided to design what is known as the “Domain Name Servers” (DNS), these translate the IP address into names by binding the former unto the latter, e.g. 196.12.157.157 is mapped unto rwandatel.rw. It is much easier to recall the name rather than the IP address. 

The IPs is used by the computers to communicate.  You would simply type www.rwandatel.rw instead of the IP.  

The problem would arise in that, the customers of MTN might not know the IP addresses of those of RWANDATEL or ARTEL, there is a likelihood that, the same IP is used by some three different people, one on each network. 

To solve this, ISOC decided to divide the IP addresses into categories, Private and public IP addresses.   Of course, the private ones were left free for all to use, as long as they are used within a private network, there is no problem. 

The Public category was reserved for only the ISPs, these are used to interconnect the ISP to one another worldwide.  There is a problem in that, in order for networks to be able to communicate, they must have a common protocol, with the mixture of IPs, and this was a problem. 

However, devices called “Routers” were designed, these can in lay man’s language be defined as translators, and they receive information from one network and translate it to be sent on to another network. 

An example is, RWANDATEL tries to communicate with MTN, but because each has a different IP, they cannot talk to each other and hence, they have to introduce devices that connect their two networks to each other, those devices are routers, these will receive traffic from one network, filter it and pass it on to their own network.

This process goes on from one ISP to another until the whole world is covered.  In brief, that is how the internet works.  We shall be covering more and more of the related topics in our future issues.
 
eddie@afrowebs.com

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