关键词：HTTP协议；互联网；传输层；应用层
摘 要：While the Internet is designed to accommodate multipletransport and application layer protocols, a large andgrowing fraction of Internet traffic runs directly overHTTP. Observing that HTTP is poised to become thede-facto “narrow waist” of the modern Internet, thispaper asks whether an HTTP narrow waist, comparedwith the an IP-layer waist, facilitates a more evolvableInternet. Evolvability is highly desirable for the Internet,since communication patterns change must faster thanthe underlying infrastructure. Furthermore, the narrow waist plays in important role in enabling or preventingarchitectural evolvability. We argue that HTTP is highlyevolvable, due to (i) naming flexibility, (ii) indirectionsupport, and (iii) explicit middleboxes. We point toevolving uses of HTTP on today’s Internet, and designingour own publisher/subscribe service, HTTP RelayService (HTTP-RS), on top of HTTP.