Ethernet, MTU’s and the efficiency of the Internet

Ethernet or IEEE802.3 is the backbone of out whole worldwide internet system, used in offices, and the connections to the main backbone of the internet.

It has a variable called the MTU or Maximum Transmission Unit, which is basically the physical packet size that data is transmitted around in in the ISO OSI 7 layer model, which is a set of standards that all are communications systems are based on historically.

Anyway we live in a world on Mega bytes and Giga bytes these days, but our basic communication infrastructure is still based on a maximum MTU of 1536 bytes. Now this is a little short sighted to say the least. This is written into every bit of hardware to do with the internet, all our routers, switches, and the very chips that send and receive Ethernet communications in our very computers.

Also given the fact that each packet of IP (Internet Protocol) has several levels of headers there is also an extra overhead involved of 20 bytes plus some sometimes on every packet.

Then there are the TCP based headers for protocols like HTTP which is the thing you see at the beginning of every web address, that you probably ignore. This protocol header is text, a number of lines just as you would type it followed by a blank line followed by whatever HTML content there is. It also contains things like the dreaded cookies everyone is so worried about for tracking there surfing.

TCP stands for Transmission Control Protocol, which harps back to the days of dumb terminals and workstations which were the predecessors of our modern computers only connected back to mainframe computers rather than the internet.

All this adds up to a slow antiquated system, the MTU should be able to be at least a mega byte for streaming say video on YouTube for example, or even a modern web page.

You can calculate the average overheads, but they are significant particularly with the environment in mind. This system is just not green, I will go on to explain further why in another post about HTML…

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