draft-ietf-httpbis-connect-tcp
Template-Driven HTTP CONNECT Proxying for TCP
TCP proxying using HTTP CONNECT has long been part of the core HTTP
specification. However, this proxying functionality has several
important deficiencies in modern HTTP environments. This
specification defines an alternative HTTP proxy service configuration
for TCP connections. This configuration is described by a URI
Template, similar to the CONNECT-UDP and CONNECT-IP protocols.