Louis Pouzin at INRIA coined the term datagram for use in his CIGALE/CYCLADES
network around 1974.
vint
At 07:17 PM 9/23/2002 -0700, Dave Crocker wrote:
At 06:46 PM 9/23/2002 -0700, Fred Baker wrote:
A packet is a unit of data carried in a packet network,
this just moves the question over the definition of a packet network. (I was
trying to compress things.)
regardless of the layer. For some reason, we generally refer to layer two
packets as 'frames' (such as Ethernet, Frame relay, or LAPB 'frames'), X.25
packets as 'packets', and TCP packets as 'segments'.
please note your use of the word "generally". as I said, use of these terms
is flexible.
I can point out literature that refers to each of those as 'packets'.
that was my point.
But a datagram is quite clearly defined.
I believe the term datagram predates IP and seem to recall hearing it during
the late 70's and early 80's in non-IP venues.
The fact that it is well defined for one use does not mean that the definition
is, well, definitive.
...from the application's perspective, a wad of data is directed to a
specified destination, and the application can essentially fire and forget.
I could imagine the APEX folks using the term "datagram" in that latter sense.
indeed locking the term down for Apex is probably the more useful path.
(but it is slightly amusing that your definition is the same as I used for
packet-switching...)
d/
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Dave Crocker <mailto:dave(_at_)tribalwise(_dot_)com>
TribalWise, Inc. <http://www.tribalwise.com>
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Vint Cerf
SVP Architecture & Technology
WorldCom
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