[ih] mssage vs. packet (was: Re: Early Internet history)

[John Day]

In the ARPANET, a message could be up to 8 packets.

> On Jul 7, 2018, at 20:48, Jack Haverty <jack at 3kitty.org> wrote:
> 
> As The Judge recently pointed out, it's impossible to define colloquial
> technical terms like "email".  I suspect "message" and "packet" are
> similarly imprecise.
> 
> Personally, I've always thought that the distinction is that a "message"
> is a self-contained and complete unit of information, that makes sense
> to both the endpoint sender and receiver.  You send a whole "message" to
> some destination, and the destination can only use it after the entire
> message is received.
> 
> A "packet" is something that some communications mechanism uses to
> actually transport data, driven by pragmatic and engineering concerns.
> E.g., packet sizes might be set based on expected error rates due to noise.
> 
> So, messages get chopped up into packets; or maybe even several messages
> get packaged into one packet.  It's up to the communications machinery
> (or its designers) to decide, based on local conditions.
> 
> Messages get sent between users, who decide what constitutes a complete
> unit of useful information.
> 
> Of course, one player's packets might also actually be another player's
> messages.  SMTP messages get carved up into IP datagrams which were
> carved up into pieces that were sent between endpoint IMPs, which were
> carved up into other pieces that actually traversed wires between IMPs.
> These chunks were packets or messages depending on your viewpoint.
> 
> /Jack
> 
> 
> 
> On 07/07/2018 04:15 PM, Dave Crocker wrote:
>> 
>>> Kleinrock's analysis was for message switching but the mathematics of 
>>> message switching and packet switching are essentially comparable 
>>> especially when you consider variable length messages.
>> 
>> 
>> Howdy.
>> 
>> A question to the group...
>> 
>> That distinction coincidentally surfaced in a discussion a couple of 
>> months ago, after some decades of my not hearing it.
>> 
>> I know what it meant on the Arpanet.  And I know what wikipedia and some 
>> other entries say about it.  But while the ability to handle smaller 
>> chunks independently -- and even in an overlapping manner -- encourages 
>> some useful performance improvements, I find myself generally thinking 
>> of them as the same category of communications technology.
>> 
>> Namely:  Discrete segments of data being handled through a network. 
>> Certainly for some form of multiplexing and possibly with dynamic 
>> routing.  (These days, we'd take stat mux and dynamic routing as 
>> inherent, but my recollection is that 45 years ago, those were 
>> variations being played with.)
>> 
>> I'm not looking to re-start the religious wars on the distinction but am 
>> curious whether, from the perspective of those 45 years and global 
>> scaling, it is fair to have most discussions -- I emphasize most, not 
>> all -- treat them as the same construct?
>> 
>> If not, why not?
>> 
>> 
>> d/
>> 
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