Hi!
I made some further investigation, did the following:
I made the following setup: 1000 packets to be sent without any delay between
them, every packet is 1100 bytes long, and the following network conditions:
1. Client-server is on the same computer (localhost)
2. Client-server on different computer, 100Mbit network intranet connection
3. Client-server on different computer, GPRS (EDGE) intranet connection
On the first case there was no problem, everything worked fine. On the 2nd and
3rd case my program was unable to detect most of the packets (in case 2 about
200 of 1000 were detected on the client side, in the 3rd case less than 100).
The OnDataAvailable method of TWSocket I use for detecting the datagrams:
procedure Tmainform.udplistenDataAvailable(Sender: TObject; Error: Word);
var Len : Integer;
Src : TSockAddrIn;
SrcLen : Integer;
begin
SrcLen := SizeOf(Src);
Len := udplisten.ReceiveFrom(@incomingbuff, SizeOf(incomingbuff),
Src,SrcLen);
incomingsize:=len;
if Len >= 0 then
begin
if (FServerAddr.S_addr = INADDR_ANY)or(FServerAddr.S_addr
=Src.Sin_addr.S_addr) then
begin
workwithincomingdata(inet_ntoa(Src.sin_addr),ntohs(Src.sin_port),incomingbuff,len);
end;
end;
end;
I used Ethereal for viewing the incoming data, and all (or at least most of)
the UDP packets was received according to Ethereal, but my program was unable
to capture them.
What am I doing wrong? Or is it a normal behaviour?
Thanks for your help:
Andras
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Francois PIETTE
Sent: Saturday, March 19, 2005 2:45 PM
To: ICS support mailing
Subject: Re: [twsocket] UDP datagramreceive periodically freezes for seconds
Use a sniffer to see if the datagrams are really sent by your program. If
they are sent, it means you have a device that drop packets, maybe when his
buffer if full. You can use the free sniffer Ethereal (link on the links
page at my website). If the datagrams are not sent, then there is something
wrong on your computer or program. Much more difficult to know what. You
should first try the exe on another computer to see what happend.
Remember UDP is by design a non reliable protocol.
--
[EMAIL PROTECTED]
http://www.overbyte.be
----- Original Message -----
From: "Udvari András László" <[EMAIL PROTECTED]>
To: "ICS support mailing" <twsocket@elists.org>
Sent: Saturday, March 19, 2005 1:52 PM
Subject: FW: [twsocket] UDP datagramreceive periodically freezes for seconds
> Anybody has any other idea, in which direction should I look for the
solution?
>
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Udvari András László
> Sent: Friday, March 18, 2005 8:26 AM
> To: ICS support mailing
> Subject: RE: [twsocket] UDP datagramreceive periodically freezes for
seconds
>
> Sorry, it was my fault, the UDP datagrams are sent with a TWSocket, not a
TWSocketServer.
>
>
> The listening TWSocket DataAvailable method is the following (partly from
the example project bound to ICS):
>
> procedure Tmainform.udplistenDataAvailable(Sender: TObject; Error: Word);
> var Len : Integer;
> Src : TSockAddrIn;
> SrcLen : Integer;
> begin
> SrcLen := SizeOf(Src);
> Len := udplisten.ReceiveFrom(@incomingbuff, SizeOf(incomingbuff), Src,
SrcLen);
> incomingsize:=len;
> if Len >= 0 then
> begin
> if (FServerAddr.S_addr = INADDR_ANY)or(FServerAddr.S_addr =
Src.Sin_addr.S_addr) then
> begin
>
workwithincomingdata(inet_ntoa(Src.sin_addr),ntohs(Src.sin_port),incomingbuf
f,len);
> end;
> end;
> end;
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Wilfried Mestdagh
> Sent: Thursday, March 17, 2005 9:12 PM
> To: ICS support mailing
> Subject: Re: [twsocket] UDP datagramreceive periodically freezes for
seconds
>
> Hello Udvari,
>
> TWSocketServer does not handle UDP, only TCP.
>
> ---
> Rgds, Wilfried
> http://www.mestdagh.biz
>
> Thursday, March 17, 2005, 16:28, Udvari András László wrote:
>
> > Hi List,
>
> > I wrote a little client-server application, which measures UDP
> > datagram transfer speed. The server is using TWSocketServer, and sends
> > a 1500 byte length UDP datagram in every half seconds. The number of
> > datagrams to be sent is a parameter, tipically some 100, below 1000.
> > The client side receive these packets measures the speed
> > (bytes/second) and the counts the missing or lost packets (every
> > packet has an incremental unique id).
>
> > But on the client side there is a strange behaviour: in about every
> > minute no datagram is coming for some seconds, and after that all of
> > them coming in one bunch, like if emptying some kind of buffer. After
> > that everything returns normal for about another 1 minute.
>
> > Is it a normal behaviour, or am I doing something wrong? On the
> > server side everything seems to be OK, according to log file every
> > packet is sent with correct timing.
>
> > Thanks for your help:
> > Andras
>
--
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