In nature evolution occurs throughout various different things. Also evolution occurs in technology. Take for instance, ATM was an evolution of frame relay, and frame relay was an evolution of packet switching. Evolution happens everywhere but in technology it happens all the time.
Packet switching technology breaks down messages into fixed-length pieces called packets and sent through a network individually. In packet switching messages are segmented into packets of a pre determined size before they are sent. This process is called packetizing. The packets are normally 1000 bytes long. There is a lot of error protection in the packet. Packet switching networks are made to run several alternative high-speed paths from one node to another. For instance if a node from San Francisco is trying to send a message to Los Angeles and the connection is busy or down, it will redirect its message to Denver then to Los Angeles as an alternative route.
Frame relay is packet switching’s next of kin. Frame relay evolved from packet switching. Instead of sending packets frame relay sends frames. " A frame has a one-byte header, two addressing and control bytes, a variable-length data field (1-64000 bytes), a 16-bit cyclic redundancy check, and a termination byte."Tcom book. In frame relay, there is hardware, on both ends of the connection that builds and breaks down frames. They do this through all kinds of data streams, LAN packets, digital voice, and asynchronous terminal input and the hardware writes the frames serially. The reason frame relay is more popular and better evolved than packet switching is that it uses commonly available circuits, which provides good throughput, and has low latency and is easy to configure. Packet switching is only good for data transferring and is sent through one type of line. Frame relay sends more information faster and through multi forms of connections. This makes packet switching not the suitable choice for ISP’s. Thus leaving packet switching out of the picture in that field of that business. Many ISP’s us frame relay as a customer access technology, for port aggregation and local traffic switching by ISP’s is the fastest growing segment of the frame relay market. Leaving packet switching in the dust.
However frame relay is not top dog in data transfers. Another form of transferring has evolved from frame relay, which is ATM (Asynchronous transfer mode). It is also known as cell relay. This form was created to solve the problem of delays in the transferring. It gets really annoying when you watch a video and it keeps on skipping or stopping every few seconds. That is an idea of a delay in data transferring. Its cells use fixed packets of 53 bytes. Theses cells can also be built and broken down like frame relay, but in a faster time. All forms of data, like voice, video, and data, can be sent through a single ATM line, at the same time (like a T3 line). A large amount of bandwidth is required to use ATM. However frame relay may be the more efficient way to go. Do to the fact that it cost more for ATM lines that it does for frame relay.
Right now frame relay is the efficient source of data transfer, but in the future as multimedia features grow the need for ATM will grow with it as well. Having the best isn’t always better. It may cost more than what you want to spend. From packet switching to frame relay to ATM, they all evolved from each other. Taking existing technology and improving it for the time it is needed for.