Network Working Group M. Kerwin
Internet-Draft
Intended status: Standards Track August 18, 2014
Expires: February 19, 2015

HTTP/2 Segments
draft-kerwin-http2-segments-01

Abstract

This document introduces the concept of “segments” to HTTP/2, and adds a flag to the DATA frame type to allow the expression segments.

Status of This Memo

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Table of Contents

1. Introduction

This document extends HTTP/2 [I-D.ietf-httpbis-http2] by introducing the concept of “segments” to HTTP/2, as a mechanism to combat the effects of fragmentation within a stream. It does this by adding a new flag to the DATA frame type ([I-D.ietf-httpbis-http2], Section 6.1).

1.1. Notational Conventions

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in [RFC2119].

2. Segments

A “segment” is a contiguous region of a HTTP/2 message’s payload data which can be freely fragmented and recombined. A segment is expressed by marking all but the final frame in the segment with the SEGMENT_CONTINUES flag (Section 4). Any data-bearing frame that does not have the SEGMENT_CONTINUES flag set, and does not follow one that does, comprises a single segment.

Segments can be used to mitigate the effects of fragmentation within a stream. For example, an endpoint may have a large chunk of data which it has to transmit via multiple DATA frames in order to comply with frame size limits. It can mark those frames as a single segment so that any downstream peer without the same frame size restrictions knows that it can safely coalesce the frames.

3. SETTINGS_USE_SEGMENTS Setting

The following new SETTINGS parameter ([I-D.ietf-httpbis-http2], Section 6.5.2) is defined:

4. SEGMENT_CONTINUES Flag

The following new flag is defined for the DATA frame ([I-D.ietf-httpbis-http2], Section 6.1):

5. Security Considerations

6. IANA Considerations

This document updates the registry for settings in the “Hypertext Transfer Protocol (HTTP) 2 Parameters” section.

6.1. HTTP/2 Settings Registry Update

This document updates the “HTTP/2 Settings” registry ([I-D.ietf-httpbis-http2], Section 11.3). The entries in the following table are registered by this document.

Name Code Initial Value Specification
SETTINGS_USE_SEGMENTS TBD N/A Section 3

7. Normative References

[I-D.ietf-httpbis-http2] Belshe, M., Peon, R. and M. Thomson, "Hypertext Transfer Protocol version 2", Internet-Draft draft-ietf-httpbis-http2-14, July 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.

Author's Address

Matthew Kerwin EMail: matthew@kerwin.net.au URI: http://matthew.kerwin.net.au/