from
The Free On-line Dictionary of Computing (8 July 2008)
segmentation
reassembly
SAR
segmentation and reassembly
<networking> (Or "segmentation and reassembly", SAR) Breaking
an arbitrary size {packet} into smaller pieces at the
transmitter. This may be necessary because of restrictions in
the communications channel or to reduce {latency}. The pieces
are joined back together in the right order at the receiver
("reassembly"). Segmentation may be performed by a {router}
when routing a packet to a network with a smaller maximum
packet size.
The term "segmentation" is used in {ATM}, in {TCP/IP}, it is
called "fragmentation" an is performed at the {IP} layer
before the "fragments" are passed to the {transport layer}.
See for example {ATM forum} {UNI} 4.0 specification.
[Better reasons?]
(1999-06-14)