Segmentation
<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?]
