Internet Engineering Task Force (IETF)                         M. Tuexen
Request for Comments: 6096            Muenster Univ. of Applied Sciences
Updates: 4960                                                 R. Stewart
Category: Standards Track                                         Huawei
ISSN: 2070-1721                                             January 2011

Stream Control Transmission Protocol (SCTP) Chunk Flags Registration

Abstract

   This document defines the procedure for registering chunk flags with
   the Internet Assigned Numbers Authority (IANA) for the Stream Control
   Transmission Protocol (SCTP).  It updates RFC 4960 and also defines
   the IANA registry for contents for currently defined chunk types.  It
   does not change SCTP in any other way.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6096.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
     3.1.  Updated IETF-Defined Chunk Extension  . . . . . . . . . . . 3
     3.2.  New IETF Chunk Flags Registration . . . . . . . . . . . . . 4
     3.3.  Initial Registrations . . . . . . . . . . . . . . . . . . . 4
       3.3.1.  DATA Chunk Flags  . . . . . . . . . . . . . . . . . . . 4
       3.3.2.  INIT Chunk Flags  . . . . . . . . . . . . . . . . . . . 5
       3.3.3.  INIT ACK Chunk Flags  . . . . . . . . . . . . . . . . . 5
       3.3.4.  SACK Chunk Flags  . . . . . . . . . . . . . . . . . . . 5
       3.3.5.  HEARTBEAT Chunk Flags . . . . . . . . . . . . . . . . . 5
       3.3.6.  HEARTBEAT ACK Chunk Flags . . . . . . . . . . . . . . . 5
       3.3.7.  ABORT Chunk Flags . . . . . . . . . . . . . . . . . . . 5
       3.3.8.  SHUTDOWN Chunk Flags  . . . . . . . . . . . . . . . . . 5
       3.3.9.  SHUTDOWN ACK Chunk Flags  . . . . . . . . . . . . . . . 6
       3.3.10. ERROR Chunk Flags . . . . . . . . . . . . . . . . . . . 6
       3.3.11. COOKIE ECHO Chunk Flags . . . . . . . . . . . . . . . . 6
       3.3.12. COOKIE ACK Chunk Flags  . . . . . . . . . . . . . . . . 6
       3.3.13. ECNE Chunk Flags  . . . . . . . . . . . . . . . . . . . 6
       3.3.14. CWR Chunk Flags . . . . . . . . . . . . . . . . . . . . 6
       3.3.15. SHUTDOWN COMPLETE Chunk Flags . . . . . . . . . . . . . 6
       3.3.16. AUTH Chunk Flags  . . . . . . . . . . . . . . . . . . . 7
       3.3.17. ASCONF ACK Chunk Flags  . . . . . . . . . . . . . . . . 7
       3.3.18. PAD Chunk Flags . . . . . . . . . . . . . . . . . . . . 7
       3.3.19. FORWARD TSN Chunk Flags . . . . . . . . . . . . . . . . 7
       3.3.20. ASCONF Chunk Flags  . . . . . . . . . . . . . . . . . . 7
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 7
   5.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
   6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 8

1. Introduction

   [RFC4960], which currently defines the Stream Control Transmission
   Protocol (SCTP), provides a procedure to define new chunk types.
   However, several protocol extensions currently being discussed need
   to define new chunk flags for existing chunks.

   This document updates RFC 4960 to overcome this limitation.  It
   defines the procedure to register chunk flags and specifies the
   registry entries for existing chunk types.  The protocol is not
   changed in any other way.  Therefore, only Section 14.1 of [RFC4960]
   is affected.

2. 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].

3. IANA Considerations

   Section 3.1 provides the updated procedure for SCTP Chunk Type
   registration; it replaces Section 14.1 of [RFC4960].

   Section 3.2 provides a new procedure for SCTP Chunk Flag
   registration.  A registry entry must be created for each SCTP Chunk
   Type.

   Section 3.3 provides the SCTP Chunk Flag registry values for the SCTP
   Chunk Types specified in [RFC3758], [RFC4820], [RFC4960], [RFC4895],
   and [RFC5061].

3.1. Updated IETF-Defined Chunk Extension

   The assignment of new chunk type codes is done through an IETF Review
   action, as defined in [RFC5226].  Documentation of a new chunk MUST
   contain the following information:

   a)  A long and short name for the new chunk type;

   b)  A detailed description of the structure of the chunk, which MUST
       conform to the basic structure defined in Section 3.2 of
       [RFC4960];

   c)  A detailed definition and description of intended use of each
       field within the chunk, including the chunk flags if any.
       Defined chunk flags will be used as initial entries in the chunk
       flags table for the new chunk type;

   d)  A detailed procedural description of the use of the new chunk
       type within the operation of the protocol.

   The last chunk type (255) is reserved for future extension if
   necessary.

   For each new chunk type, IANA creates a registration table for the
   chunk flags of that type.  The procedure for registering particular
   chunk flags is described in the following Section 3.2.

3.2. New IETF Chunk Flags Registration

   The assignment of new chunk flags is done through an RFC required
   action, as defined in [RFC5226].  Documentation of the chunk flags
   MUST contain the following information:

   a)  A name for the new chunk flag;

   b)  A detailed procedural description of the use of the new chunk
       flag within the operation of the protocol.  It MUST be considered
       that implementations not supporting the flag will send '0' on
       transmit and just ignore it on receipt.

   IANA selects a chunk flags value.  This must be one of 0x01, 0x02,
   0x04, 0x08, 0x10, 0x20, 0x40, or 0x80, which MUST be unique within
   the chunk flag values for the specific chunk type.

3.3. Initial Registrations

   This section describes the initial values of the chunk flag tables,
   one table for each chunk.  Most tables are currently empty.  IANA
   used these values to create the new registry.

3.3.1. DATA Chunk Flags

            +------------------+-----------------+-----------+
            | Chunk Flag Value | Chunk Flag Name | Reference |
            +------------------+-----------------+-----------+
            | 0x01             | E bit           | [RFC4960] |
            | 0x02             | B bit           | [RFC4960] |
            | 0x04             | U bit           | [RFC4960] |
            +------------------+-----------------+-----------+