Re: [lwip-users] Slow HTTP put request

[jochen]

> You should capture the traffic on your customer premises to make sure
> this is what's happening. I'm curious to know.

Below is the trace of our customer. I think if you look at packets 
around no 2552 for example it shows the same behavior as curl in my 
understanding. Labview is waiting with a 1 sec timeout for the server 
reply to expect/continue which does not happen and then continues to 
send the 1 byte payload. This slows down the PUT dramatically.

My server has also implemented POST and here the payload is received 
without any delay (packets around no 2540). It seems there is no 
additional "expect/continue handshake" implemented?

I found an article (link below) regarding labview && POST and as I 
understand using POST this "handshake" is only done if the message is 
greater than 1024. For PUT there is no such limit ?

I see the following solution:
- server sends reply to expect/continue and then... well, frankly don't 
know exactly what happens then and how much overhead this means
- force labview to "HTTP 1.0" w/o expect/continue ... if this is 
possible ?
- implement an "application specific protocol" in labview as suggested 
in the article below ?
- use POST instead of PUT for my "TWI write" function in order to speed 
up transfers below 1024 bytes ?

Let me know if this thread is getting off-topic.

Links:
https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019LuWSAU

labview_post.pcapng
Description: Binary data

labview_put.pcapng
Description: Binary data