From: jds@math.okstate.edu (Jennifer "Moira" Smith)
Subject: [rec.games.mud]: FAQ #3/3: RWHO and "mudwho"
Followup-To: rec.games.mud.misc
Summary: info on rwho servers, and mudwho
Keywords: muds rwho mwhod mudwho
Supersedes: <faq_rwho_717919204@math.okstate.edu>
Reply-To: jds@math.okstate.edu
Organization: Oklahoma State University, Math Department
Date: Fri, 16 Oct 1992 06:00:24 GMT
Expires: Sat, 14 Nov 1992 06:00:03 GMT

Archive-name: mud-faq/part3
Version: $Id: faq.rwho,v 2.9 92/09/15 18:53:55 jds Exp $

FREQUENTLY ASKED QUESTIONS: Basic Information on RWHO and "mudwho"

This is part 3 in a 3 part series of FAQs.

What Is RWHO?
-------------

        RWHO stands for 'Remote WHO'.  It's a way of getting a WHO list
from a MUD, without even having to connect to that MUD at all.  Anyone
can get this output from a RWHO server (an 'mwhod'), by using straight
telnet to connect to a certain port (6889), or by using the client program
'mudwho'.  RWHO servers talk to other mwhods, passing information around,
and are talked to directly by some MUDs, receiving information from them. 
Any one mwhod keeps track of several MUDs, plus storing information passed
it from other mwhods.  Only MUDs that have the RWHO routines compiled in
will be able to send their WHO list info to a mwhod.  UnterMUDs have this
capability built in; other MUDs have to have the routines installed first.
The RWHO routines have been installed into TinyMUSH, TinyMUCK, LPMUD,
DikuMUD, and AberMUD, without encountering any difficulty.


How Does It All Work?
---------------------

        'mwhod' is the RWHO server that runs on a particular host and
keeps a list of known MUDs. It is initially primed with a list of "trusted"
MUDs and passwords used for authentication, and will accept information
about who is logged into those MUDs. The server also has a notion of
a "peer" server, which can transfer it (occasionally) a copy of all of
its list of who is logged on, and where. The idea is that the whole
MUDding community could probably be served pretty well by about 5 peer
mwhods that kept each other up to date about what each one is seeing.

        Communication between mwhods (and server updates sent to mwhods)
is done with UDP datagrams, since they're fast, nonblocking, and
throw-away. (RWHO information is considered to be interesting but not
vital information, if you get my drift). Each MUD server only sends
updates to a single mwhod, which may then propagate that information
to its peers. This is done within the MUD server as follows:

        - whenever the server boots, it sends a "hi there" packet to
         the mwhod, telling it that it's up and running.
        - whenever a player connects, it sends a "so and so is here"
         packet to the mwhod, telling it that the user has connected.
        - whenever a player disconnects, it sends a "so and so left"
         packet to the mwhod, telling it to delete the entry.
        - every so often ("so often" being defined as a time agreed
         upon by the mwhod's owner, and the MUD's wizard, usually
         every 5 minutes or so) the MUD sends a "hi there" packet
         and a complete list of everyone that is on, just to refresh
         the mwhod's idea of who is logged into that MUD.

        If a user connects to a specific port (6889) of a host machine
running an mwhod they are given a formatted dump of the mwhod's current
table of MUDs and players, and then disconnected. "mudwho" is a simple
little program that contacts an mwhod and downloads this information. 
Ideally, the functionality of "mudwho" would be built into a player's
client software, for ease of use. Two handy options can be used by 
"mudwho", if the netlag to the mwhod server isn't too bad. The options
are "-u <username>", and "-m <mudname>". If received before the timeout,
the mwhod will then only dump WHO list information for the specified
player or MUD.

        The mwhod does some clever stuff as far as eventually timing
information about of its tables - for example, if it hears absolutely
nothing from a MUD for a certain amount of time, it will mark the MUD
as down. Player entries are expired similarly. The design is based on
the idea that we'll use UDP to just fling information out and hope it
sticks, and then let the recipient clean it up, rather than to develop
a more complex protocol based on TCPs and timeouts. To prevent a packet
circular send situation, each entry that is sent is given a "generation"
number, which is incremented by one each time it is forwarded along. In
this manner, a MUD server might send a "so and so is here" (generation
zero) to its local mwhod. The local mwhod will eventually send a copy to
any peers it may have (generation one), and so forth. Part of the initial
table that an mwhod uses to establish what peers it trusts contains a
generation value, and it will neither accept nor propagate information
to a specific peer that is of a higher generation value. This way, a
"tree" of servers could theoretically be constructed, with the highest
level one having a total view of a large MudIverse.


Where Can I Get This Stuff?
---------------------------

        The client program "mudwho" can be ftp'd from ftp.math.okstate.edu
(139.78.10.6), in pub/muds/clients.  The shar file contains both
mudwho.c and a README file, listing a few mwhod sites.  The plain "mudwho.c"
file can be found at decuac.dec.com (192.5.214.1).

        The RWHO routines can be ftp'd from decuac.dec.com (192.5.214.1),
in pub/mud.  Included is a HOW_TO file, which describes how to plug
the routines into a MUD server, and also where to ask for a mwhod to use.

        The mwhod program itself can also be found on decuac, but there is
currently little need for another one running in the USA.  There is, however,
only one running in Europe, and further expansion may need to be made in
that area. 


Where Are Some RWHO Servers?
----------------------------

Currently, all of these servers talk to each other, so what one knows, 
the rest will know, with the exception of the mwhod in Germany, which only
talks to the mwhod on moebius.math.okstate.edu (so only moebius has
the RWHO information from Europe currently). At any one time, there's an
average of 20 muds, of various types, talking to mwhods.

Site                         IP           Port  Admin
------------------------------------------------------------------------------
riemann.math.okstate.edu     139.78.1.15  6889  jds@math.okstate.edu
amber.ecst.csuchico.edu      132.241.1.43 6889  warlock@ecst.csuchico.edu
nova.tat.physik
  .uni-nuebingen.de          134.2.62.161 6889  gamesmgr@taurus.tat.physik
                                                .uni-tuebingen.de

------------------------------------------------------------------------------
  This posting has been generated as a public service.  If you have any
  suggestions, questions, additions, comments or criticisms concerning this
  posting, contact Moira (jds@math.okstate.edu).  Other Frequently Asked
  Questions (FAQ) postings contain information dealing with MUDs, MUDding,
  clients, servers, and ftp sites.  While these items aren't necessary,
  they make the game much more playable.  I'd also like to thank Marcus J.
  Ranum (mjr@decuac.dec.com) for writing such a wonderful program (and
  decent docs), and everyone else for helpful comments and suggestions. The
  most recent versions of these FAQs are archived on ftp.math.okstate.edu
  (139.78.10.6) in pub/muds/misc/mud-faq, plus on rtfm.mit.edu (18.172.1.27)
  in the news.answers archives.  Have fun! - Moira

-- 
Jennifer Smith
jds@math.okstate.edu
On MUDs: Moira, RosaLil, Jasra, etc.	      |   It's the terror of knowing
Here, have a clue. Take two, they're small.   |    What this world is about
Newsgroups: rec.games.mud.announce,rec.games.mud.misc,alt.mud,news.answers