When a virtual server has an HTTP profile with compression enabled, which traffic is compressed by the BIG-IP?

When an HTTP profile with compression is assigned to a virtual server, the BIG-IP acts as a full proxy and compresses eligible response traffic on the clientside connection - from the BIG-IP to the client. Compression is selective because the HTTP profile evaluates content-type headers and URI patterns to determine which responses qualify, rather than compressing every byte sent to the client.

Compression is a clientside operation on responses; the BIG-IP does not compress all server-side traffic - it may actually decompress server responses before re-compressing them for clients.

Traffic from pool members to the BIG-IP is inbound server-side traffic; compression is not applied in this direction by the HTTP compression profile.

Not all clientside traffic is compressed - only responses that match the HTTP profile's configured content-type filters and URI criteria are eligible for compression.