Packets.

Thrasher · Post by **Thrasher** » Wed Mar 24, 2004 3:16 am

What type of packets does Zdoom use for network play, and what size are they?

HotWax · Post by **HotWax** » Wed Mar 24, 2004 1:56 pm

I'm pretty sure it uses UDP, but I have no idea what size the packets would be. They probably vary in size depending on the number of players and other factors.

Post by **randi** » Thu Mar 25, 2004 10:04 am

HotWax is correct: UDP and the packet size varies depending on what needs to be sent (although they are usually quite small since the only things that are being sent most of the time are your movements).

Bu2d · Post by **Bu2d** » Thu Mar 25, 2004 10:18 pm

How do you minimize the amount of packets sent?

HotWax · Post by **HotWax** » Thu Mar 25, 2004 11:38 pm

The default setting IS the minimum number of packets. If you're experiencing consistancy failures, you can use the -dup X parameter to send 2 or more copies of each packet, which increases bandwidth requirements but also increases the liklihood that at least one packet will reach its destination intact and on time.

I believe the -net setting can also be used to reduce the amount of data sent and recieved by each client, as they only send their data to the server. (By default, Doom clients send data to all other computers)

Biff · Post by **Biff** » Sun Mar 28, 2004 9:32 am

I'm pretty sure that a few corrections are needed.

The command argument to send extra (backup) packets is -extratic.

The -dup argument (-dup 2, -dup 3, etc.) will reduce the number of packets. For example, -dup 2 will send a packet every two game tics, -dup 3 will send a packet every three game tics. This can help speed up the game on limited-bandwidth connections, usually at the expense of some smoothness of movement.

The network setting argument is -netmode 1. The default is -netmode 0 and this is the original peer-to-peer mode where all computers send data to all other computers. With three players or more, -netmode 1 will cause each client to communicate only with the host. This helps a lot to reduce data "collisions" on a LAN with a large number of players.

HotWax · Post by **HotWax** » Sun Mar 28, 2004 1:29 pm

Uhhh, I think you have -dup and -extratic backwards...

Biff · Post by **Biff** » Sun Mar 28, 2004 9:05 pm

Could be, I'll look for backup info, unless Randy can help out here. We used to use the -dup command to get the game (doom2.exe) up to speed on 14.4 modems, especially with three or more players, never did use the -extratic back then.

Post by **randi** » Sun Mar 28, 2004 10:34 pm

Biff is correct.

HotWax · Post by **HotWax** » Mon Mar 29, 2004 12:12 am

Great. So I've been using (and recommending) the -dup command to reduce consistency failures for about a year now and all I've been doing is making things worse... Why has nobody corrected me before now?!

Biff · Post by **Biff** » Mon Mar 29, 2004 4:50 pm

It may not have made consistency failures much worse, hard to say. We've still had some problems with con failures even using -extratic, with more "advanced" zdoom maps and also with bots in some conditions. If you think you know what happened in the game to cause the failure, Randy still might be able to use the information to squash another multiplayer bug.

QBasicer · Post by **QBasicer** » Thu May 06, 2004 6:26 pm

Why can't ZDoom use TCP? Wouldn't that make it less likely to loose packets?

Post by **Bio Hazard** » Thu May 06, 2004 8:54 pm

because randy dosent want to code it maybe?

Post by **Kate** » Thu May 06, 2004 9:36 pm

There are already ports for that: they're called skulltag (Forum) and zdaemon.