[PD] thoughts on Pd's networking framework

[Ivica Ico Bukvic]

So, we've tried to do a series of tests using tcpserver/client as well as netserver/client and found the following:

Using either off-the-shelf wifi hardware or an industrial strength wifi router (in our case Cisco), we get unexpected lag spikes on local WLAN with 16 clients at times even exceeding 2 seconds for some of the clients.

Network connection in these tests was unencrypted.

Packets tested were small to medium using both UDP and TCP (from a single number, up to a sentence, plus a couple numbers).

When using off-the-shelf router we even had clients drop connections to the router in a high-traffic context. By using an industry strength router these took much longer to occur (but have still nonetheless occurred).

So, with the router being less likely of a culprit I am wondering what is causing these spikes?

Without looking closely at Pd's network code one suggested culprit by a CS colleague might be how Pd reuses ports and a possibility of it starving the router. Is this possible?

The problem is apparent when sending sporadic TCP packets to all 16 machines as well as when using both UDP and TCP connections.

One last thought is whether there might be something on the router settings that would make this an issue in both cases.

Any thoughts on this would be most appreciated.

Ivica Ico Bukvic, D.M.A.
Composition, Music Technology
Director, DISIS Interactive Sound & Intermedia Studio
Director, L2Ork Linux Laptop Orchestra
Assistant Co-Director, CCTAD
CHCI, CS, and Art (by courtesy)
Virginia Tech
Dept. of Music - 0240
Blacksburg, VA 24061
(540) 231-6139
(540) 231-5034 (fax)
ico at vt.edu
http://www.music.vt.edu/faculty/bukvic/