Data Socket gets slow

[YSKIMO57]

Hello,

I made CVI data-socket connection between two PC's.

When I run it in the same machine, it runs ok - up to 1 kHz, or higher.

But when I run it over the Internet (in the same office), it gets very slow.

It is so even when I use a cross-over cable (not using the LAN),

directly connecting two PC's; the speed drops down 10 Hz.

Is data-socket performance supposed to be this low?

Or do I miss any necessary network setup between the two computers?

Any suggestion will be appreciated.

Thanks,

YK.

[Jack J.]

Hello YK,

What kind of data are you transfering over your datasocket? The size of each packet will also effect your transmission rate.

According to this KB, you should be able to get up to 320 KB/s

Also, how are you evaluating the speed of the datasocket? Are you just seeing the number of times new data is available or are you using a different method?

Regards,

Jack J.

Applications Engineer
National Instruments

[YSKIMO57]

Thanks for the reply, Jack.

The transmitting data is very simple one: just a single number of float.

Data socket is sending that number every some (1/ 10/ 100) milliseconds in a while loop.

What I'm concern is Data socket's performance in two cases:

Method #1: a single data transfer in each and every loop (say, a single float number, 1000 times of transfer command (1 kHz)).

Method #2: one package with some data in it with lower transfer rate (say, 100 data array, with 10 times (10 Hz) of transfer command).

I know method #2 is definately better for network program (I may need buffering technique).

But the delay time is very imporant in my application, so I'm seeking a way, other than buffering.

So my questions are:

- Can the speed of 320 KB/s be achieved regardless the number of tranfer command?

- Or only for continuous transfer rate under single/few transfer command?

- If fewer transfer command is highly-recommended, what is the performance for it? Any KB for this issue? (e.g. Overhead of calling command).

- Any technique recommended for minimizing the network delay?

Thanks,

YK.