Process flow for LTM 11.5.1

Assuming this is HTTP, and you are talking about HTTP compression, and the F5 is doing the Decryption (SSL-offload) client-side, then the compression happens just before data is encrypted (ssl) and sent to client. That is, IF a compression profile is attached to the LTM virtual server.

If the F5 receives a response from the server, and it is compressed, it will generally be transmitted unmodified to the client (headers in http 1.1 are uncompressed), in some cases, you will need to configure the HTTP Profile to remove the Accept-Encoding on the server-side if you have a need to inspect on HTTP payload, and need to have it uncompressed.

Note that unmodified here means that the overall TCP stream will be identical at the application layer, however, at the TCP layer, you may have slightly different sized packets, and in some cases, even the HTTP chunks may differ in size.

Let me know if this answers, or if you have additional questions.