VS: [lwip-users] speed and delay question with uc/os-ii

[Jarkko Loima]

Hi!

I noticed that, windows 2k & CAsynckSocket was bottleneck, not lwip. I
still have a little delay and CRC-failures otherwise system works fine.

-Jarkko


>Thanks for quick answer.
>
>I have to send either (4260) Bytes once in 100mS or 73 Bytes in every
2mSec...
>
>Buffering & sending data with TCP is more reliable way but it takes
about 20mSec to send that packet. Reason for problems >is that i'm using
interrupt driven system and sending data through TCP overrides all lower
level interrupts. If i chabge >prioritys of interrupts incoming data is
ok but TCP-start's sending out of order & retransmissions...
>
>So what would you suggest? Do you think that i could send UDP-packet
once in every 2mSec?
>
>Other end is w2k Visual C++, program with casynckSocket...
>
>-JLoima

Quoting "K.J. Mansley" <address@hidden>:

> On Wed, 2004-08-25 at 09:13, address@hidden wrote:
> > Hi!
> >
> > I'm using lwip with uc/os-ii. I'd like to know which is the wastest 
> > &
> delayless
> > way to send data (size of data to send is about 4260 Bytes).
> >
> > I'm using TCP with netconn_write() at the moment but have a little 
> > problems
> with
> > delay (20 ms) & retransmissions...
> >
> > So, is UPD faster way or should i use tcp_write() or something like 
> > that???
> I
> > think that with UDP i could get rid of these retransmissions.
>
> The raw API (e.g. tcp_write() etc) will be faster than using netconn_*
>
> UDP may make a small difference, as it's a simpler protocol, but if 
> you're losing data you'll need to do retransmissions whatever 
> transport protocol you choose.  I would try to work out why data need 
> to be retransmitted, and address that.  If you are just doing a single

> short transfer over each connection you may find UDP helps by not 
> having the "slow start" phase of TCP.
>
> Hope that helps,
>
> Kieran
>
>
>
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>




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