Network Working Group Bo. Chen Internet-Draft Hui. Chen Expires: December 22, 2007 Xiaodong. Lee Feng. Wang CNNIC,China June 20, 2007 Telephone Number Mapping (ENUM) Service Registration for MGCP draft-chenbo-enum-mgcp-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on December 22, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Chen, et al. Expires December 22, 2007 [Page 1] Internet-Draft ENUM-MGCP June 2007 Abstract MGCP decomposes a multimedia gateway into two parts, a call agent and a media gateway,thus brings greater extensibility and makes it easy to construct a large-scale VoIP network. This document registers the MGCP Enumservice according to the guidelines given in RFC 3761 [3].This kind of Enumservice is mainly applied in Carrier Networks. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. MGCP Service Registration . . . . . . . . . . . . . . . . . . 4 3. Address of record in MGCP . . . . . . . . . . . . . . . . . . 5 4. The 'E2U+MGCP' Enumservice . . . . . . . . . . . . . . . . . . 6 5. Example of E2U+MGCP Enumservice and scenes for application . . 7 5.1. Example of E2U+MGCP Enumservice . . . . . . . . . . . . . 7 5.2. The scenes for MGCP-ENUM application . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 8.1. Normative References . . . . . . . . . . . . . . . . . . . 11 8.2. Informative References . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12 Intellectual Property and Copyright Statements . . . . . . . . . . 13 Chen, et al. Expires December 22, 2007 [Page 2] Internet-Draft ENUM-MGCP June 2007 1. Introduction ENUM (E.164 Number Mapping, RFC 3761 [3]) is a system that uses DNS to translate telephone numbers into URIs. By using DNS services like delegation through NS records and NAPTR records, one can look up what services are available for a specific E.164 number. As an improvement of H.323, MGCP assumes a call control architecture where the call control "intelligence" is outside the gateways and handled by external call control elements MGC(Media Gateway Controller)known as Call Agents, while MG(Media Gateway) is just responsible for the media conversion. MGCP defines the interaction messages between them. Moreover, MGCP assumes that these call control elements, or Call Agents, will synchronize with each other to send coherent commands and responses to the gateways under their control because MGCP does not define a mechanism for synchronizing Call Agents. This document registers the MGCP Enumservice according to the guidelines given in RFC3761 [3]. The MGCP Enumservice is used in the services field of a NAPTR resource record which indicates what class of functionality a given end point offers. As shown in part 5.2, ENUM-MGCP is mainly used in carrier networks, making a unified addressing intra or inter MGCP system or even between other VoIP systems and MGCP systems. Chen, et al. Expires December 22, 2007 [Page 3] Internet-Draft ENUM-MGCP June 2007 2. MGCP Service Registration Enumservice Name: "MGCP" Enumservice Type: "mgcp" Enumservice Subtype: N/A URI Scheme: "mgcp:" Functional Specification: see Section 4 Security considerations: see Section 6 Intended Usage: COMMON Author: Bo. Chen (chenbo@cnnic.cn) Any other information that the author deems interesting: None Chen, et al. Expires December 22, 2007 [Page 4] Internet-Draft ENUM-MGCP June 2007 3. Address of record in MGCP The address of MGCP end-points includes two parts. One is the domain name of attributive gateway, the other is the local name of this terminal in the gateway. Local name uses the form of physical interface/circuit number. For example, a MGCP address hrd4/56@gw23.example.net:5060 means that the attributive gateway is gw23.example.net, using port 5060, and the physical interface is hrd4 , while the circuit number is 56. Chen, et al. Expires December 22, 2007 [Page 5] Internet-Draft ENUM-MGCP June 2007 4. The 'E2U+MGCP' Enumservice Traditionally, the services field of a NAPTR record contains a string that is composed of two subfields: a 'protocol' subfield and a 'resolution service' subfield. ENUM in particular defines an 'E2U' (E.164 to URI) resolution service. This document defines an 'E2U+ mgcp' Enumservice for MGCP. The scheme of the URI that will appear in the regexp field of a NAPTR record using the 'E2U+mgcp' Enumservice is 'mgcp'. Chen, et al. Expires December 22, 2007 [Page 6] Internet-Draft ENUM-MGCP June 2007 5. Example of E2U+MGCP Enumservice and scenes for application 5.1. Example of E2U+MGCP Enumservice The following is an example of the use of the Enumservice registered by this document in a NAPTR resource record. $ORIGIN 9.2.1.3.1.8.8.5.0.1.6.8.e164.arpa. IN NAPTR 10 100 "u" "E2U+mgcp" "!^.*$!mgcp:hrd4/56@example.cn!" . 5.2. The scenes for MGCP-ENUM application Part of MGCP's address of record is physical interface/circuit number which should be unknown to end-users, so ENUM-MGCP is not for one dedicated user but for carriers.With the help of ENUM-MGCP, the calls, no matter intra MGCP system, inter MGCP system, or from other VoIP systems, can have a unified addressing. There are three scenes as below.In these scenes, T1 represents terminal1,while T2 represents terminal2,and arrows show the call signal. Scene 1: the ENUM-based call procedure in the same MGCP system MGC1 receives a call request from T1. After querying ENUM system, MGC1 has found that the call would terminate in the same MGCP system, then it makes a direct connection to MG12. +------+ +--------+ +-------+ |MG11 | --------> | MGC1 | --------> | MG12 | +------+ +--------+ +-------+ ^ / ^ \ / \ / \ / v \ v +------+ +----------+ +-------+ | T1 | | ENUM | | T2 | +------+ +----------+ +-------+ the ENUM-based call procedure in the same MGCP system Scene 2: the ENUM-based call procedure among different MGCP systems MGC1 receives a call request from T1. After querying from ENUM system, MGC1 has found that the call would terminate in another MGCP system, then it makes a connection to the relative call agent MGC2. Chen, et al. Expires December 22, 2007 [Page 7] Internet-Draft ENUM-MGCP June 2007 +------+ +------+ +-----+ +-----+ |MG11 | ----> | MGC1 | -----> | MGC2| ---> |MG21 | +------+ +------+ +-----+ +-----+ ^ / ^ \ / \ / \ / v \ v +------+ +----------+ +-----+ | T1 | | ENUM | | T2 | +------+ +----------+ +-----+ the ENUM-based call procedure among different MGCP systems Scene 3: the ENUM-based call procedure between other VoIP systems and MGCP systems The call agent of other VoIP systems, such as sip or H.323 based systems, receives a call request from T1. After ENUM query, it would find that the caller is MGCP-based. It then makes a connection to the attributive MGC using a MGCP-based signal. +-----------+ +----+ | | +------+ +------+ | T1 | ------>| other VoIP| -----> | MGC | ----> | MG | +----+ | H.323 sip | +------+ +------+ | | \ +-----------+ / ^ \ \ v / +-----+ v \ | T2 | +-----------+ +-----+ | ENUM | +-----------+ the ENUM-based call procedure between other VoIP systems and MGCP systems Chen, et al. Expires December 22, 2007 [Page 8] Internet-Draft ENUM-MGCP June 2007 6. Security Considerations All the security problems and resolutions described in RFC3761 [3] is available here.The security issues associated with this Enumservice have not been assessed. Chen, et al. Expires December 22, 2007 [Page 9] Internet-Draft ENUM-MGCP June 2007 7. IANA Considerations This document registers the E2U+MGCP ENUM service according to specifications and guidelines in RFC 3761 [3] and the definitions in this document. Chen, et al. Expires December 22, 2007 [Page 10] Internet-Draft ENUM-MGCP June 2007 8. References 8.1. Normative References [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [2] Andreasen, F. and B. Foster, "Media Gateway Control Protocol(MGCP) Version 1.0", RFC 3435, January 2003. [3] Faltstrom, P. and M. Mealling, "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)", RFC 3761, April 2004. [4] Foster, B. and F. Andreasen, "Basic Media Gateway Control Protocol (MGCP) Packages", RFC 3660, December 2003. [5] Foster, B. and C. Sivachelvan, "Media Gateway Control Protocol(MGCP) Return Code Usage", RFC 3661, December 2003. 8.2. Informative References [6] Arango, M., Dugan, A., Elliott, I., Huitema, C., and S. Pickett, "Media Gateway Control Protocol (MGCP) Version 1.0", RFC 2705, October 1999. Chen, et al. Expires December 22, 2007 [Page 11] Internet-Draft ENUM-MGCP June 2007 Authors' Addresses Bo,Chen CNNIC,China 4 South 4th Street,Zhongguancun,Haidian District Beijing 100080 China Email: chenbo@cnnic.cn Hui,Chen CNNIC,China 4 South 4th Street,Zhongguancun,Haidian District Beijing 100080 China Email: chenhui@cnnic.cn Xiaodong,Lee CNNIC,China 4 South 4th Street,Zhongguancun,Haidian District Beijing 100080 China Email: lee@cnnic.cn Feng,Wang CNNIC,China 4 South 4th Street,Zhongguancun,Haidian District Beijing 100080 China Email: fengw@cnnic.cn Chen, et al. Expires December 22, 2007 [Page 12] Internet-Draft ENUM-MGCP June 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Chen, et al. Expires December 22, 2007 [Page 13]