ATM Lines

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 switchingís 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 ISPís. Thus leaving packet switching out of the picture in
that field of that business. Many ISPís us frame relay as a customer access
technology, for port aggregation and local traffic switching by ISPís 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 isnít 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.