Keith Moore has released an Internet-Draft, On the use of HTTP as a Substrate for Other Protocols, describing guidelines for creating protocols like XML-RPC and SOAP that use HTTP as a transport mechanism.

Miles Sabin pointed out the draft on XML-Dev, noting that "might be of interest to the XML-RPC and SOAP communities".

This working draft notes that:

"the recent interest in layering new protocols over HTTP has raised a number of questions when such use is appropriate, and the proper way to use HTTP in contexts where it is appropriate."

After examining security and architecture concerns, the author concludes that while HTTP may be a useful substrate, these protocols should not be considered part of HTTP or rely too heavily on its security: "New protocols or services should use new URL types," "New services should define their own error reporting mechanisms,"and "All protocols should provide adequate security."