WCF: reducing first call delay. Best practice

Question

I have WCF client that connects to server in Intranet. The very first call takes significant time and user waits patiently until it completes. Second, third calls are at least 30% faster.

What is the best practice to keep WCF client ready to call? I'm thinking about background thread that pings server from time to time (or may be the very first time application starts) but may be there are better/simpler ways?

Service is IIS6 hosted with wsHttp(Dual)Bindings. Problem is serious with Dual endpoint.

Answer 1

This behavior could be related to the fact that the application pool in IIS is not loaded into memory when the first request arrives.