The Network Interface Card (NIC) has came a long way...

One of the convinces of today's computers is the ability to connect to a network or the internet any place any time.

What makes this possible is the Network Interface Card or more commonly known as the NIC.

When the first NIC's were introduced by today's standards they were slow, very slow.

One of the first networks were called token ring.

Here is how it works:

A token ring network is a ring, all computers on the network must be connected and it is a contiguous (unbroken) ring. If one computer drops off the ring then the network stops, dead, no communication to any other computer is possible.

Each computer's Network Interface Card uses a code called a Machine Address Code or MAC the NIC software adds the MAC code to the message being sent, it also adds the MAC of the receiving computer to the message.

This combined message is called a Token, the message is sent to the next computer on the ring. If the message has the same MAC address in the Token as the computer that received the message then the computer does not retransmit the message. But if the MAC code doesn't match the code in the Token it retransmits the message.

Thus the Token goes from one computer to the next in the ring until it reaches the computer the message was for.

Token Ring Networks were slow, around 4MBPS (Mega Bits Per Second).

Luckily for us Ethernet was the next step in the evolution of the NIC!

When Ethernet was introduced the NIC's had a transmit speed of 5MBPS. With in a year the speed was at 10MBPS.

The advantage of Ethernet over Token Ring is that the message goes to all computers on the network, if the MAC code in the message doesn't match the computer receiving the message the Network Interface Card ignores the message.

The 5 Steps to high quality and cheap DIY Computer Repairs Get It Today...

However there is a fly in the ointment, the first Ethernet were half duplex, that is the NIC could only send or receive not both at the same time (the technology wasn't there yet).

Another reason Half Duplex is slow because the transmitting NIC has to wait until there is not any network traffic on the network before transmitting it's message.

It will take a few years for technology to get to a point where the NIC can transmit and receive simultaneously, this will be called Full Duplex.

The transmitting NIC sends out a short message for the receiving computer, this is called a poll, if the receiving computer is on the network it sends back an ACK message, then the transmitting NIC sends the message to the receiving computer. This is still true with 100MBPS and 1GBPS NIC's today, it is just faster.

It will also take sometime before Ethernet can transmit faster than 10MBPS, the standard will 100MBPS for over twenty years once the technology is developed.

Today's NIC's, hubs, and some routers can transmit at up to 1 GBPS (Giga Bits Per Second) and there is a new standard of 5 GBPS under testing.

The more you dig in to the Network side of your computing the more complex it gets from the hardware to the software.

See this page Network Interface Card for troubleshooting your NIC...

As a famous British Comic/Magician Tommy Cooper used to say: "It's Magic!"