[MUD-Dev] Net protocols for MUDing (was: Moore's Law sucks)

[J C Lawrence]

On Tue, 24 Feb 1998 01:41:56 PST8PDT 
Chris Gray<cg at ami-cg.GraySage.Edmonton.AB.CA> wrote:
> [Chris L:] 

>> The key feature of TCP which I'd remove would be the
>> error correction. Given a predictive client its both unecessary and
>> counter-productive.

> Only to a certain extent. Sure, you can probably cruise over a bit
> of lost data in graphics or audio output. Missing some text from the
> middle of a paragraph could be a bit shocking to the average user,
> however. 

True, but how about a client which gradually paints the text as it is
received ala interlaced GIFs, and thus went thru the following display
sequence:

--<cut>--
  <***> brief gasp as you enter this place, your surprised gulp
  accompanied by an exciting tingle that thrills your spine in an
  electric <***>oom. The fresco on closer inspection details all that
  is Parrius; <***>othy surf, within which <***>n some kind of
  effortless metamorphosis, rising up to show the city itself,
  encircled by white walls <***>iant virgin white seagull. To look any
  more on this munificent architectural creation would surely create a
  <***>all.
--<cut>--

which mutates a second later into:

--<cut>--
  Central chamber of collegiate learning.  

  About you all is bathed in light. You allow yourself a brief gasp as
  you enter this place, your surprised gulp accompanied by an exciting
  tingle that thrills your spine in an electric <***>oom. The fresco
  on closer inspection details all that is Parrius; <***>othy surf,
  within which <***>n some kind of effortless metamorphosis, rising up
  to show the city itself, encircled by white walls <***>iant virgin
  white seagull. To look any more on this munificent architectural
  creation would surely create a giddiness the likes of which no human
  could withstand, and so you reluctantly close your eyes a while so
  that you may absorb the aesthetic energy of it all.
--<cut>--

Which in turn turns into:

--<cut>--
  Central chamber of collegiate learning.  

  About you all is bathed in light. You allow yourself a brief gasp as
  you enter this place, your surprised gulp accompanied by an exciting
  tingle that thrills your spine in an electric manner. Here all is
  flooded in a spectacular light, as clear as the light of day itself,
  highlighting a continuous fresco imprinted on to the circular wall of
  the room. The fresco on closer inspection details all that is Parrius;
  <***>othy surf, within which <***>n some kind of effortless
  metamorphosis, rising up to show the city itself, encircled by white
  walls <***>iant virgin white seagull. To look any more on this
  munificent architectural creation would surely create a giddiness the
  likes of which no human could withstand, and so you reluctantly close
  your eyes a while so that you may absorb the aesthetic energy of it
  all.
--<cut>--

And then finally as the last packets come in::

--<cut>--
  Central chamber of collegiate learning.

  About you all is bathed in light. You allow yourself a brief gasp as
  you enter this place, your surprised gulp accompanied by an exciting
  tingle that thrills your spine in an electric manner. Here all is
  flooded in a spectacular light, as clear as the light of day itself,
  highlighting a continuous fresco imprinted on to the circular wall
  of the room. The fresco on closer inspection details all that is
  Parrius; a continuous rolling wave headed by a frothy surf, within
  which swim magnificent battleships that bear the Augustine emblem
  with proud fortitude. And the waves then become land in some kind of
  effortless metamorphosis, rising up to show the city itself,
  encircled by white walls that encircle the city as if they were the
  wings of some giant virgin white seagull. To look any more on this
  munificent architectural creation would surely create a giddiness
  the likes of which no human could withstand, and so you reluctantly
  close your eyes a while so that you may absorb the aesthetic energy
  of it all.
--<cut>--

The text BTW is taken from the welcome room at Avalon.

I'd note that the above gets very interesting if you also interpolate
the updates for the speech that was going on at the time.  Consider
the effect of dropped packets in the following full text:

--<cut>--
  Central chamber of collegiate learning.

  About you all is bathed in light. You allow yourself a brief gasp as
  you enter this place, your surprised gulp accompanied by an exciting
  tingle that thrills your spine in an electric manner. Here all is
  flooded in a spectacular light, as clear as the light of day itself,
  highlighting a continuous fresco imprinted on to the circular wall
  of the room. The fresco on closer inspection details all that is
  Parrius; a continuous rolling wave headed by a frothy surf, within
  which swim magnificent battleships that bear the Augustine emblem
  with proud fortitude. And the waves then become land in some kind of
  effortless metamorphosis, rising up to show the city itself,
  encircled by white walls that encircle the city as if they were the
  wings of some giant virgin white seagull. To look any more on this
  munificent architectural creation would surely create a giddiness
  the likes of which no human could withstand, and so you reluctantly
  close your eyes a while so that you may absorb the aesthetic energy
  of it all.
  - 
  A mighty voice booms, "You are offending me with your foul
  language. huggie scum".
  - 
  A deep voice shouts, "I fight plenty alone... I fight at my choice".
  - 
  Somebody shouts, "Sopare us, ok?".
  - 
  A deep voice shouts, "Cmon fuckwit fight".
  - 
  A tall fellow strides into view. He shakes you by the hand.
  -
--<cut>--

> Also, the channel back from the client to the server should
> not lose any of the user's input. What you want is the ability to be
> sure that if a message arrives, then it is the complete message that
> was sent, not some fragment of one. You will also want to do your
> own checks on any header of the message, since UDP doesn't even
> guarantee correctness. (It typically is correct over ethernet,
> because of the way ethernet works, but it isn't over SLIP, for
> example, which is one reason why you shouldn't run NFS over a SLIP
> link.)

True.  Both directions need TCP-like error correction.  However the
downside has no/little need (post protocol state machines may say
otherwise) to delay delivery of any individual packet.  Essentially
this involves devolving the upside protocol to require consistent
transactions, not a correct stream.

> If the system gets a bit smarter, with some caching in the client,
> then some sort of reliable protocol will be needed, both ways, to
> co-ordinate that cache.

Nahh.  You can make the entire cache protocol advisory.  ie each end
broadcasts publisher/listener style (well, sorta) what he
has/needs/wants, with the other end picking up on them as they wish,
and the requestor repeating until satisfied as needed (see earlier
discussion of well evolved object heirarchies with the graphical
presentation of objects gradually refining as the more exact (lower on
the object heirarchy) representations were received).

--
J C Lawrence                               Internet: claw at null.net
(Contractor)                               Internet: coder at ibm.net
---------(*)                     Internet: claw at under.engr.sgi.com
...Honourary Member of Clan McFud -- Teamer's Avenging Monolith...