DCCP-UDP: A Datagram Congestion Control Protocol UDP Encapsulation for NAT Traversal
RFC 6773
Internet Engineering Task Force (IETF) T. Phelan
Request for Comments: 6773 Sonus
Updates: 4340, 5762 G. Fairhurst
Category: Standards Track University of Aberdeen
ISSN: 2070-1721 C. Perkins
University of Glasgow
November 2012
DCCP-UDP: A Datagram Congestion Control Protocol UDP Encapsulation for
NAT Traversal
Abstract
This document specifies an alternative encapsulation of the Datagram
Congestion Control Protocol (DCCP), referred to as DCCP-UDP. This
encapsulation allows DCCP to be carried through the current
generation of Network Address Translation (NAT) middleboxes without
modification of those middleboxes. This document also updates the
Session Description Protocol (SDP) information for DCCP defined in
RFC 5762.
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/rfc6773.
Phelan, et al. Standards Track [Page 1]
RFC 6773 DCCP-UDP Encapsulation November 2012
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. DCCP-UDP . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. The UDP Header . . . . . . . . . . . . . . . . . . . . . . 5
3.2. The DCCP Generic Header . . . . . . . . . . . . . . . . . 5
3.3. DCCP-UDP Checksum Procedures . . . . . . . . . . . . . . . 6
3.3.1. Partial Checksums and the Minimum Checksum
Coverage Feature . . . . . . . . . . . . . . . . . . . 7
3.4. Network-Layer Options . . . . . . . . . . . . . . . . . . 8
3.5. Explicit Congestion Notification . . . . . . . . . . . . . 8
3.6. ICMP Handling for Messages Relating to DCCP-UDP . . . . . 8
3.7. Path Maximum Transmission Unit Discovery . . . . . . . . . 9
3.8. Usage of the UDP Port by DCCP-UDP . . . . . . . . . . . . 9
3.9. Service Codes and the DCCP Port Registry . . . . . . . . . 11
4. DCCP-UDP and Higher-Layer Protocols . . . . . . . . . . . . . 11
5.1. Protocol Identification . . . . . . . . . . . . . . . . . 12
5.2. Signalling Encapsulated DCCP Ports . . . . . . . . . . . . 13
5.3. Connection Management . . . . . . . . . . . . . . . . . . 14
5.4. Negotiating the DCCP-UDP Encapsulation versus Native
DCCP . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.5. Example of SDP Use . . . . . . . . . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
7.1. UDP Port Allocation . . . . . . . . . . . . . . . . . . . 17
7.2. DCCP Reset . . . . . . . . . . . . . . . . . . . . . . . . 17
7.3. SDP Attribute Allocation . . . . . . . . . . . . . . . . . 17
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1. Normative References . . . . . . . . . . . . . . . . . . . 18
9.2. Informative References . . . . . . . . . . . . . . . . . . 18
Phelan, et al. Standards Track [Page 2]
RFC 6773 DCCP-UDP Encapsulation November 2012
1. Introduction
The Datagram Congestion Control Protocol (DCCP) [RFC4340] is a
transport-layer protocol that provides upper layers with the ability
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