World: r3wp

So that we can't currently

Yeah .. just did a packet trace and it's all UDP

R3 does not contain UDP in networking device low level code?

not yet

Steeve, what's the algorithm for reading data from a port when you 
don't know how much data is coming down?

Does each arrival of data trigger a 'read event?

and does it append to port/data ?

some internals on how low level networking code works - http://www.rebol.net/wiki/TCP_Port_Details

yep graham

# Setup the IO-request data and length fields. Data is the buffer 
tail position. Length is the buffer space available from above. Clear 
the actual field.

so it does an append

but don't forget to execute a [read port] each time you received 
a packet , to be able to receive the futher one.

so you need to do a read port inside the read event?

yep

all this word overloading drives me crazy!

packet are append to port/data but the index is not moved

eh?

so how to read until there is no more data ?

no "eh?" me !!!
:-)

so the index is used by ??

there is no way to know how much packets can be received.
Your protocol has to send this info, if not you're tricked

why should every data be read first? Why is not 'read even triggered 
on new data arrival = change of buffer size?

actually the read function ask to the server to send the next packet 
to the client, if any.
You may receive a packet (event read triggered) or not.

Do we need to clear the port data after a read ?

or before a read ?

eg. copy port/data clear port/data read port ?

you do as you want

the packet is added to port/data

so if we 

copy port/data read port copy port/data .. we will get duplicate 
data ?

yes

ok.

so no more data is appended to the port/data until we ask for it 
using a read port

it's your duty to clear or remove/part data in the buffer

yup

My duty is clear ...

so with a write port ... the buffer is filled with my write data, 
it gets sent, and then cleared by the tcp device

no

write port data, can use any buffer

if you use the same buffer (ie port/data) for read and write, you 
may encounter some problems

i will not use the same buffer for read and write

I'm sure I read that write port uses the port/data as its buffer

no, the write function uses any buffer you want as parameter

because it's a parameted

*parameter

hm... I think we are not talking the same thing
http://www.rebol.net/wiki/TCP_Port_Details

says that the port/data is used by write

The details of the port actor for WRITE are:


   1. Set port/data to WRITE content (binary string) value. (Mainly 
   to keep it GC safe.)

   2. Obtain binary string as specified. The buffer is not copied. This 
   is a low level mechanism.
   3. Determine start position from index.

   4. Determine length from tail-index or from /part if specified.

   5. Set IO-request length and data. Zero the actual field (the length 
   actually transferred).
   6. Call the TCP device with the IO-request
   7. Check for errors

   8. Check for immediate completion. If done, set port/data to NONE.

So, this means that the port/data buffer is recreated on each read 
after a write

strange, you may be right

sometimes I am known to be right ....

not often ...