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DirectPlay Overhead

Started by JonShute Mar 3, 2000 at 9:48 AM 3 replies 1.5k views

Original Post

Mar 3, 2000 at 9:48 AM

I know it is conventional wisdom that DirectPlay adds overhead to the connection but I was wondering if anybody had actually verified this? Does anybody know of any hard data to support this? The reason I''m asking is that I am about to evaluate DirectPlay for a project and I don''t want to reinvent the wheel if I can''t help it.

SiCrane

Mar 3, 2000 at 1:34 PM

Running a simple chat program (64 bytes of data sent per packet) in a basic sockets implementation versus a directplay implementation, directplay showed a 6-10% network bandwidth overhead according to a packet sniffer. This was run over seven trials, hence the variable overhead number. To make it a more real trial we used a subnet where five guys were playing Quake2, but there was no other traffic.

DeVyle

Mar 3, 2000 at 2:15 PM

SiCrane in your tests did you turn off the DirectPlay IDTag and automatic messaging features? I cannot think of any reason why there would be that much overhead if you turn off the extra features.

Eagerly awaiting your response,

Nick V. Caldwell
MIT c\o ''03
nvc@mit.edu

SiCrane

Mar 3, 2000 at 2:59 PM

Here are the flags used:

IDirectPlay::Send was called as unsigned, unencrypted but guaranteed.
IDirectPlay::Receive was called with no flags.

DPSESSIONDESC2 structure was create with DPSESSION_CLIENTSERVER, DPSESSION_NODATAMESSAGES, DPSESSION_NOMESSAGEID.

The chat program was run with 10 clients. Each client ran a script that sent 1000 lines of text and joined/left 10 times. Each client computer ran the same script in both DPlay and Winsock. However each client computer ran a different script.

JonShute

Mar 4, 2000 at 6:32 AM

I think I feel a detailed investigation coming on.

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