| 3.3 | Layer 2 Protocol Overview - WAN Protocols | ||
| 3.3.12 | ATM cell format |
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ATM transfers information in fixed-size
units called cells (analogous to frames). Each cell consists of 53
bytes. Cell relay is a flexible and responsive method for multiplexing
all forms of digital traffic (data, voice, image, and video). Cell
relay can handle rapid changes in the quantity and pattern of the
traffic in a network. All traffic is placed in fixed-length packets of
information (cells) and switched at high speeds. Cell relay is
considered by many to be the best multiplexing technology for modern
communication applications because it combines the strengths of
time-division multiplexing (TDM) and conventional packet switching.
Using cell-relay packet-handling techniques, a mixture of bursty and
delay-sensitive traffic can be processed simultaneously, while at the
same time providing the services required by each traffic type. Also,
because cell-relay processing is based on the use of small packets,
the process technology is adaptable to a wide range of interface
speeds.
ATM is unique in its use of fixed-size
cells. The cell format is shown in Figure
This curriculum will not explore ATM troubleshooting. That will be left for another course. An excellent reference for ATM is the recent Cisco Press book "Cisco ATM Solutions".
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