Network Working Group E. Wilde Internet-Draft Swiss Federal Institute of Expires: June 26, 2002 Technology December 26, 2001 Registration of GSTN SMS Service Qualifier draft-wilde-sms-service-00 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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 June 26, 2002. Copyright Notice Copyright (C) The Internet Society (2001). All Rights Reserved. Abstract This memo describes the registration of the Short Message Service (SMS) as a registered IANA service selector for Global Switched Telephone Network (GSTN) numbers. SMS is not available for all GSTN subscribers, but it has proven very popular with users of the Global System for Mobile Communications (GSM), and has also been adapted to other telephone network technologies such as the Integrated Services Digital Network (ISDN). Wilde Expires June 26, 2002 [Page 1] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 What is GSM? . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 What is SMS? . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.1 SMS content . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.2 SMS infrastructure . . . . . . . . . . . . . . . . . . . . . 4 2. IANA registrations . . . . . . . . . . . . . . . . . . . . . 4 2.1 IANA registration form for GSTN address service-selector "SMS" . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 IANA registration form for GSTN address qualit-type1 keyword "SMSC" and value . . . . . . . . . . . . . . . . . . . . . . 5 3. Security Considerations . . . . . . . . . . . . . . . . . . 6 Normative References . . . . . . . . . . . . . . . . . . . . 7 Non-Normative References . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . 8 A. Where to send Comments . . . . . . . . . . . . . . . . . . . 8 B. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 Full Copyright Statement . . . . . . . . . . . . . . . . . . 9 Wilde Expires June 26, 2002 [Page 2] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 1. Introduction The capitalized 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 RFC 2119 [RFC2119]. 1.1 What is GSM? GSM (Global System for Mobile Communications) is a digital mobile phone standard which is used extensively in many parts of the world. First named after its frequency band around 900 MHz, GSM-900 has provided the basis for several other networks utilizing GSM technology, in particular GSM networks operating in the frequency bands around 1800 MHz and 1900 MHz. When referring to "GSM" in this document, we mean any of these GSM-based networks that operate a short message service. 1.2 What is SMS? The Short Message Service [SMS] is an integral part of the GSM network technology. It has been very successful and currently is a major source of revenue for most GSM operators. SMS as a service is so successful that other Global Switched Telephone Network (GSTN) technologies have adapted it as well, in particular the Integrated Services Digital Network (ISDN). Because of this development, this memo uses the term "SMS client" to refer to user agents who are able to send and/or receive SMS messages. 1.2.1 SMS content GSM SMS messages are alphanumeric paging messages that can be sent to and SMS clients. SMS messages have a maximum length of 160 characters (7-bit characters from the GSM character set [SMS-CHAR]), or 140 octets. Other character sets (such as UCS-2 16-bit characters, resulting in 80 character messages) MAY also be supported [SMS-CHAR], but are defined as being OPTIONAL by the SMS specification. While the 160 character variety for SMS messages is by far the most widely used one, there are numerous other content types for SMS messages, such as small bitmaps ("operator logos") and simple formats for musical notes ("ring tones"). However, these formats are proprietary and are not considered in this memo. SMS messages are very limited in length (140 octets), so several methods exist to concatenate SMS messages. However, none of these methods is standardized, and different manufacturers of mobile phones Wilde Expires June 26, 2002 [Page 3] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 implement different methods of message concatenation. Therefore, SMS message concatenation is not taken into consideration by this memo. SMS clients composing messages may still employ concatenation methods, but they MUST be aware that they do so at their own risk, possibly using a method that is not supported by the receiving SMS client. 1.2.2 SMS infrastructure SMS messages can be transmitted over an SMS client's network interface using the signalling channels of the underlying GSTN infrastructure, so there is no delay for call setup. Alternatively, SMS messages MAY be submitted through other front-ends (for example such as Web services), which makes it possible for SMS clients to run on computers which are not directly connected to a GSTN network supporting SMS. SMS messages are stored by an entity called Short Message Service Centre (SMSC), and sent to the recipient when the subscriber connects to the network. The number of a cooperative SMSC must be known to the SMS sender (ie, the entity submitting the SMS message to a GSTN infrastructure) when sending the message (usually, the SMSC's number is configured in the SMS client and specific for the network operator to which the sender has subscribed). In most situations, the SMSC number is part of the sending SMS client's configuration. However, in some special cases (such as when the SMS recipient only accepts messages from a certain SMSC), it may be necessary to send the SMS message over a specific SMSC. Short messages can be mobile terminated (MT) or mobile originated (MO). MT messages are the ones that arrive at SMS clients; MO messages are sent by SMS clients. Networks may support either, both, or none of these. For the purpose of this memo, it is important that the sending SMS client is allowed to submit MO messages, and that the receiver is allowed to receive MT messages. The exact setup of message submission and delivery is not subject of this memo, it may incorporate additional hops in addition to the pure SMS transport. For example, the sending SMS client may use a Web service to submit the SMS message, and the receiving SMS client may be set up to forward the SMS to an email account. For the purpose of this memo, it is important that the receiver can be addressed by a GSTN number, and that the sender can submit an SMS message using this number. 2. IANA registrations Based on the requirements defined in RFC 3191 [RFC3191], the IANA Wilde Expires June 26, 2002 [Page 4] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 registration forms for the "SMS" service-selector and "SMSC" qualif- type1 elements are defined here. Syntax definitions are given using the Augmented BNF for Syntax Specifications [RFC2234]. 2.1 IANA registration form for GSTN address service-selector "SMS" To: IANA@iana.org Subject: Registration of new values for the GSTN address service-selector specifier "SMS" service-selector name: SMS Description of Use: SMS - specify that the GSTN address refers to a GSTN subscriber who is capable of receiving messages using the GSM Short Message Service (SMS). For a complete description refer to RFC 3191 and draft-wilde- sms-service-00. Security Considerations: See the Security Consideration section of draft-wilde-sms-service-00. Person & email address to contact for further information: Erik Wilde Swiss Federal Institute of Technology ETH-Zentrum 8092 Zurich Switzerland tel:+41-1-6325132 fax:+41-1-6321035 mailto:ietf@dret.net 2.2 IANA registration form for GSTN address qualit-type1 keyword "SMSC" and value To: IANA@iana.org Subject: Registration of new values for the GSTN address qualif-type1 element "SMSC" qualif-type1 "keyword" name: SMSC qualif-type1 "value" ABNF definition: The ABNF definition for the value of the SMSC keyword is taken from draft-allocchio-gstn-01 Wilde Expires June 26, 2002 [Page 5] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 sub-addr = gstn-phone gstn-phone = ( global-phone / local-phone ) global-phone = "+" 1*( DIGIT / written-sep ) local-phone = [ exit-code ] dial-number / exit-code [ dial-number ] exit-code = phone-string dial-number = phone-string phone-string = 1*( DTMF / pause / tonewait / written-sep ) DTMF = ( DIGIT / "#" / "*" / "A" / "B" / "C" / "D" ) pause = "p" tonewait = "w" written-sep = ( "-" / "." ) Description of Use: SMSC - In some situations, it may be necessary to guide the sender of an SMS message to send the message via a certain Short Message Service Center (SMSC). If the SMSC qualif-type1 element is present, an SMS client SHOULD try to send the message first using the specified SMSC. If that fails, the SMS client MAY try another SMSC (such as the default SMSC for that client). Further description is available in draft-wilde-sms-service-00 Use Restriction: The use of the "SMSC" qualif-type1 element is restricted to the "SMS" service-selector, it has no meaning outside the SMS service defined by the "SMS" service-selector. Security Considerations: See the Security Consideration section of draft-wilde-sms-service-00. Person & email address to contact for further information: Erik Wilde Swiss Federal Institute of Technology ETH-Zentrum 8092 Zurich Switzerland tel:+41-1-6325132 fax:+41-1-6321035 mailto:ietf@dret.net 3. Security Considerations SMS messages are transported without any provisions for privacy or integrity, so SMS users should be aware of these inherent security problems of SMS messages. Unlike electronic mail, where additional Wilde Expires June 26, 2002 [Page 6] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 mechanisms exist to layer security features on top of the infrastructure, there is no such framework for SMS messages. SMS messages very often are delivered almost instantaneously (if the receiving SMS client is on line), but there is no guarantee for when SMS messages will be delivered. In particular, SMS messages between different network operators sometimes take a long time to be delivered (hours or even days) or are not delivered at all, so applications SHOULD NOT make any assumptions about the reliability and performance of SMS message transmission. In most networks, sending SMS messages is not a free service. Therefore, SMS clients MUST make sure that any action that incurs costs is acknowledged by the end user, unless explicitly instructed otherwise by the end user. If an SMS client has different ways of submitting an SMS message (such as a Web service and a phone line), then the end user MUST have a way to control which way is chosen. SMS clients often are limited devices (typically mobile phones), and the sending SMS client SHOULD NOT make any assumptions about the receiving SMS client supporting any non-standard services, such as message concatenation or proprietary content types. However, if the sending SMS client has prior knowledge about the receiving SMS client, then he MAY use this knowledge to compose non-standard SMS messages. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [RFC2234] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, November 1997. [RFC3191] Allocchio, C., "Minimal GSTN address format in Internet Mail", RFC 3191, October 2001. [SMS] European Telecommunications Standards Institute, "Digital Cellular Telecommunications System (Phase 2+); Technical realization of the Short Message Service (SMS); Point-to-Point (PP)", December 1998, . Wilde Expires June 26, 2002 [Page 7] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 [SMS-CHAR] European Telecommunications Standards Institute, "Digital Cellular Telecommunications System (Phase 2+) (GSM); Alphabets and language-specific information (GSM 03.38)", July 1996, . [draft-allocchio-gstn] Allocchio, C., "Text string notation for Dial Sequences and GSTN / E.164 addresses", draft-allocchio-gstn-01 (work in progress), November 2001. [draft-wilde-sms-service-00] Wilde, E., "Registration of GSTN SMS Service Qualifier", draft-wilde-sms- service-00 (work in progress), December 2001. Non-Normative References [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. Author's Address Erik Wilde Swiss Federal Institute of Technology ETH-Zentrum 8092 Zurich Switzerland Phone: +41-1-6325132 EMail: ietf@dret.net URI: http://dret.net/netdret/ Appendix A. Where to send Comments Please send all comments about this document to Erik Wilde. Appendix B. Acknowledgements This document has been written using the IETF document DTD described in RFC 2629 [RFC2629]. Wilde Expires June 26, 2002 [Page 8] Internet-Draft Registration of GSTN SMS Service Qualifier December 2001 Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Wilde Expires June 26, 2002 [Page 9]