So, What is a Cloud?

Clouds have been around for a long time. No, I'm not talking about the groups of water droplets that sometimes are between us and the sky. The cloud has been the nickname for the general network for a long time. When a picture was drawn of two people talking together over the phone system, the picture usually had the originator (call this person 'A') talking on a phone which had a line to a cloud-shaped symbol which then had another line leading out of it to the recipient (call this person 'B') of the call. When a physical connection exists between A and B, it is called a "circuit-switched" line.

Over the years, what has actually been within that cloud has changed. Long, long ago, the contents of the cloud were a series of connected wires such that, physically, there was a single wire leading from A to B. In order to achieve this connection, various people ("operators") would use a small section of wire (called a "patch cord") to connect lengths of wire together. So, your local operator (which had ALL the local phone wires leading into the office) would connect your wire to a wire leading to a long-distance operator, who would then connect to the destination region, who would connect to a destination city who would connect to a local phone company who would then connect to B's line and then put a "ringing signal" on the line to tell B that they had a call.

The next iteration of content in the cloud was to replace part (then all) of the human operators with mechanical analog (no bits and bytes) switches. One switch type, called a "cross-bar" was an important development that allowed this progression to change. There was still, by the time a call was completed, a single physical connection from A to B.

The change from analog to digital allowed "breakage" of the physical connection. While there was still, after the call was completed, a physical connection, the form of the signal now changed from section to section of the connection. This usually meant a parallel line that contained "signal" information. The signal information includes such things as to whom the call has been placed, who made the call, when it occurred and (for billing purposes, in particular) how long the call was active.

Packet-switching broke the physical connection. Packet switching includes the address information (telephone number, etc) with the data (voice, video, music, ...). Since the address was included along with the data, it could be sent anywhere -- it could even be stored temporarily if a connection was unavailable. Finally, the Internet Protocol (IP) started to take over this type of combined address/data format.

However, when you make a call (or, access a computer or network service or whatever), you don't really know what is happening in the network -- and that is why it is still envisioned as a cloud. And, you don't really CARE how it gets from A to B as long as it gets there. It is likely to be a mixture of technologies and it just isn't important to A or B -- but it is vitally important to the providers of the network.

Modern "cloud" services rely on a packet-switched Internet Protocol network to allow access, storage, transfer, and interpretation of data. The next blog will talk about some of those specific services.