🚀 go-pugleaf

Steve Kennedy (steve@marvin.demon.co.uk) wrote:
: BEWARE running the game DOOM on Novell networks over IPX.

: This can cause broadcast storms and knock out wide area links.

: This has been verified from 2 independent sources !!!

I posted a message about this some time back (though the content was
more about filtering out the bad stuff than about warning people - there
was enough hoo-hah at the time that I thought most people would know). 
The problem is that when you have a multi-player game the players'
machines broadcast IPX frames at about 70 frames per second.  Each game
can have up to 4 players but there can be multiple games on a given LAN. 

This can have various effects: 1) less powerful (usuallyt older)
machines on the local LAN can have trouble receiving all these frames,
inspecting them and deciding they aren't interesting - reports say that
keyboard characters can be lot, for instance; 2) if you bridge between
LANs over WAN links the WAN probably won't keep up unless you've got
more than the common 56Kbps or 64Kbps; 3) if you route IPX and you have
the Cisco novell helper-address set, especially if you have it set to
flood broadcasts (e.g.  if you use NETBIOS over Novell IPX) then you can
put your routers very seriously to sleep - two players on one LAN used
100% of the CPU of our AGS+/3s propagating the broadcasts to 11 other
ethernets, an FDDI and a couple of 2Mbps serial lines. 

This problem has apparently been fixed with version 1.2 of Doom, though
I haven't checked it for myself.  Versions 0.99, 1.0 and 1.1 apparently
all exhibit this behaviour.  The authors got comprehensively flamed in
comp.sys.ibm.pc.games.action for this piece of sloppy programming.


Sam Wilson
Network Services Division
Computing Services, The University of Edinburgh
Edinburgh, Scotland, UK