File Transfer Over TCP/IP

[Guest]

HI ALL,
I HAVE GOT A VERY STRANGE PROBLEM WHILE TRANSFERRING DATA OVER INTERNET.
ACTUALLY I AM SENDING AND RECEIVING DATA BETWEEN TWO APPLICATIONS USING
TCP. WHILE SENDING OR RECEIVING DATA, I WRITE THE DATA TO NETWORK STREAM AND
THEN READ IT
FROM NETWORK STREAM.
BY DOING SO I AM ABLE TO SEND AND RECIEVE DATA OVER LAN. BUT WHEN I USE
INTERNET
CONNECTION OF SPEED AROUND 56 KBPS, THE DATA WHICH I RECEIVE IS CORRUPTED
OR IT IS NOT IN THE SEQUENCE IN WHICH IT WAS SENT. ALSO
THIS PROBLEM OCURS FOR LARGE SIZE OF DATA. FOR SMALLER DATA SIZE LIKE A
STRING, IT WORKS FINE.

ON LAN EVERYTHING WORKS FINE. THE PROBLEM OCCURS ONLY ON INTERNET.

PLEASE HELP ?

 

[Guest]

It sounds like you are using UDP and not TCP as the TCP protocol is designed
to ensure that messages arrives in sequence. If you're using TCP the
underlying network protocol would not allow that to happen.

It really does sound like you are using UDP because you would notice most
problems over the internet with UDP as packets get lost the whole time.

Brian Delahunty
Ireland

 

[Guest]

DONT QUOTE ME ON THIS
But:

I seem to remember that TCP guarantees to deliver all the packets you send
but they can be received in any order. So you could send 3 packets 1 - 2 - 3
and receive then as 2 - 3 - 1.

See http://mike.passwall.com/networking/tcppacket.html
there is a 32bit sequence number in the header

You may need to rebuild the data manually after checking the packet headers
for an order indicator or something

 

[Matthijs ter Woord]

TCP is always in the right order.


Greets,

Matthijs ter Woord