JMETER software with Ajax requests and Post HTTP method

Hello,

 

The Big-IP cluster is in version 11.5.3 no hotfix install on it. I encountered an issue with Big-IP LTM/APM. My Big-IP performed SAML authentication as SP and the IDP is an external device.

 

When I use a standard browser like Mozilla Firefox and pass through LTM/APM, the authentication works and I get the full payload HTTP but when I use JMETER software to send request to the web server passing through LTM/APM I get a part of payload HTTP, not the full data HTTP. This is occurred only when it's long request with the AJAX data combined with post http method. The result is that HTML data seems truncated.

 

No issue with get method or short ajax requests combined with post http method. It works also when I bypass the Big-IP LTM/APM. I thought to use the virtual server Performance Fast Layer 4 because It can resolve this issue but this type of virtual server can't support the APM authentication.

 

I tried to change some settings in the TCP profile like increased the proxy-buffer-high and low, enabled the selective-nack, disabled nagle and delayed-acks :

 

ltm profile tcp TCP-Prod-test { ack-on-push disabled app-service none defaults-from tcp-wan-optimized delayed-acks disabled nagle disabled proxy-buffer-high 196607 proxy-buffer-low 131072 proxy-mss enabled selective-nack enabled timestamps disabled }

 

These changes have improved the data transfert between the client and Big-IP in random way (sometimes I get more data and sometimes less data) never the full data.

 

I don't think that is an HTTP issue because no chunking is done in the server side.

 

Anyone has already encountered the kind of issue or know I can fix it without change the Virtual Server type.

 

Thank you for your help