Philip A. Prindeville (philipp@Larry.McRCIM.McGill.EDU)
Sun, 12 Jun 88 18:33:26 EDT
FRAME - lowest level of bits/bytes. One speaks of Ethernet Frames, etc
A FRAME has ONE data link header (e.g. Ethernet header).
FRAGMENT - the thing that IP spits out to the data link driver. Each
FRAGMENT has ONE IP header. A FRAGMENT may be split into
multiple FRAMES by the lower layers.
Not quite. A DATAGRAM becomes fragmented (in FRAGMENTS, of course) so that
each will fit into a FRAME. The whole purpose of the MTU and fragmentation
is to avoid lower level fragmentation and reassembly. The only exception to
this is X.25 where you have complete-packet-sequences (but since X.25
is reliable, and in order, this doesn't present a problem). Under LAN
technologies (ARCNET, PRONET, Ethernet, Token Ring, etc) 1 FRAGMENT ==
[ ... ]
DATAGRAM - this is also the 'larger' thing that IP tries to send. A
DATAGRAM USUALLY has a one to one relationship with a SEGMENT
It may be broken up (fragmented) into a number of FRAGMENTS
by IP before being sent through the data link.
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