[PD] Connection with UDP transport protocol using [netsend] or [udpsend]

Jack jack at rybn.org
Wed Feb 4 21:13:16 CET 2009


Hello,

Go back to home.
Hmm, i have done some tests using the shell and/or PHP and there is  
still this problem with UDP protocol.
So, my conclusion is i have a poor network (small LAN with Ethernet  
and WiFi and a bridge between).
I can't figure out why i loose 78% of TPDU on this simple network and  
why the TPDU lost are between 0-47 and 70-99 everytime even if i use  
the UDP protocol.
I have to dig to find and understand my problem.
++

Jack


Le 2 févr. 09 à 17:37, Jack a écrit :

> Hello Frank,
>
> You haven't read my previous mail ;)
> Yep, i know with UDP protocol, you can loose TPDU. This is the risk
> with it. You needn't any aknowledgement, any error detection/
> correction or flow detection, etc.
> My problem is :
>
> I have a problem to understand  a behaviour with the UDP transport
> protocol.
> When i connect to computer together using :
>
> Host A -> 802.3 -> Router with bridge fonction -> 802.11 -> Host B
>
> On Host A :
>
> [100(
> |
> [until]
> |
> [f  ]x[+ 1]
> |
> [send $1(
> |
> [netsend 1] or [udpsend]
>
> On Host B :
>
> [netreceive 1] or [udpreceive]
> |
> [print]
>
> 1)
> When i click on [100(, [netreceive 1] or [udpreceive]  receive only
> numbers between 48 and 69, so there is 78 number drop ! I know this a
> UDP protocol but my network is very simple (and i think there is not
> a lot of perturbations on it). It is normal ?
>
> 2)
> The other problem is strange for me :
> Why it is only numbers between 48 and 69 that arrive on the host B
> and not numbers between 34 and 56 or something else ? It's always the
> same TPDU that are lost ? Strange no ?
>
> Thanx.
> ++
>
> Jack
>
>
> Le 2 févr. 09 à 17:13, Frank Barknecht a écrit :
>
>> Hallo,
>> Jack hat gesagt: // Jack wrote:
>>
>>> In fact with TCP, everything works fine (that the aim of this
>>> protocol) with [until].
>>> If it works with TCP, it should work with UDP (or i'm wrong).
>>
>> You are a little bit wrong: The possibility to lose messages (i.e.
>> packets) is one of the "advantages" of UDP over TCP. See
>> http://en.wikipedia.org/wiki/
>> User_Datagram_Protocol#Difference_between_TCP_and_UDP
>>
>> Ciao
>> -- 
>> Frank
>>
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>
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