Internet Engineering Task Force Adam Roach Internet Draft Ericsson Inc. Category: Informational November 2000 Expires May 2001 Ringback tones in SIP-Based Telephony 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 cite them other than as "work in progress". The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/lid-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This document is an individual submission to the IETF. Comments should be directed to the authors. Abstract This document describes a mechanism by which an appropriate ringback tone may be played to the calling party when the called party's device is alerting. It is written specifcally to address the case where the Session Initiation Protocol (SIP) is used to initiate voice-over-IP calls. It also lists ringback characteristics for several countries. 1. Introduction In the current PSTN (public switched telephony network), users expect to hear an appropriate ringback tone when contacting a node in a foreign network. For example, when placing a call from the United States to Sweden, a Swedish ringback tone is heard by the caller. Further, it is currently possible that calls terminating on a PBX exchange receive special ringback tones which are distinct from those used by the PSTN in the country in which the PBX resides. Roach [Page 1] Internet Draft Ringback tones in SIP-Based Telephony November 2000 In order to ease the transition from standard circuit-switched telephony to voice-over-IP telephony, it is desirable that, when feasable, user experience remains largely the same. In the case of providing an appropriate ringback tone, doing so is quite trivial. This document defines two extension headers to SIP [1] to allow such behavior. The first, "Country," specifies the country in which the called party is located. The second, "Ringback," allows the called party to give an specific frequency and cadence for the ringback tone. Both headers are expected to be included only in "180 Ringing" responses to "INVITE" requests. 2. Client Handling If a SIP UAS (called party) wishes to suggest that a specific ringback tone be played to the calling party, it may include one or both of the "Country" or "Ringback" headers (defined below) in its "180 Ringing" responses to "INVITE" requests. For robust operation, it is strongly recommended that UASs wishing to use this extension include both headers. UACs (calling party agents) may elect to implement either or both of the "Ringback" and "Country" headers (although, for robustness sake, are encouraged to implement both). Note that low-memory embedded devices may not have the luxury of storing ringtone information for scores of countries; similarly, many clients may choose not to parse out the slightly more complicated "Ringback" syntax and instead opt to use the "Country" header exclusively. When a UAC (calling party) understanding either or both of the "Country" and "Ringback" headers receives them in a "180 Ringing" message, it can use them to generate an approprite ringback tone for the calling user. In the case that only a "Country" header is present, the ringback tone is that defined in section 4. When a "Ringback" header is present, it will define a specific tone (frequency and cadence) to be played to the calling user. In the case that the UAC understands both headers, "Ringback" is expected to take precedence over "Country." This allows the definition of custom ringback tones (e.g. for special PBX ringback). It is suggested that nodes implementing the extension described in this document also implement the "Reliability of Provisional Responses in SIP" extension [6] ; this will ensure delivery of the "180 Ringing" response. 2.1. New SIP headers Roach [Page 2] Internet Draft Ringback tones in SIP-Based Telephony November 2000 This table expands on tables 4 and 5 in RFC 2543 [1] . Header field where proxy ACK BYE CAN INV OPT REG --------------------------------------------------------- Country 180 - - - o - - Ringback 180 - - - o - - 2.1.1. SIP "Country" Header The following SIP header is defined. Country = "Country" ":" country-code country-code = 2(lower-case) lower-case = %x61-7a ; lowercase letters a-z This header is used to convey which country-specific ringback tone is to be presented to the calling party. The defined values for "country-code" and their corresponding ringback tone definitions are given in section 4. Note that the "Country" header may be generally useful in other situations which are outside the scope of this document. Draft authors are encouraged to reuse the "Country" header where appropriate. The syntax and accepted values (based on ISO 3166 [3] and the IANA TLD list [2] ) are expected remain the largely the same, with the possible addition of parameters when needed (e.g. "Country: gb;subdivision=sct"). 2.1.2. SIP "Ringback" Header The following SIP header is defined. Ringback = "Ringback" ":" frequency ";" cadence frequency = 1*DIGIT [("x" | "+") 1*DIGIT] cadence = duration ";" duration *(";" duration ";" duration) duration = 1*DIGIT ["." 1*DIGIT] When present, this header gives a specific definition of the ringback tone to be played for the calling party. The "frequency" parameter specifies the tone to be played. All frequency numbers represent a sine-wave frequency in hertz. If the frequency paremeter contins a single number, it represents a pure tone to be played. If a frequency of the format "f1 + f2" is specified, both frequencies f1 and f2 should be played Roach [Page 3] Internet Draft Ringback tones in SIP-Based Telephony November 2000 simultaneously to generate the tone. If a frequency of the format "f1 x f2" is speficied, the frequency f1 should be modulated by the frequency f2 to generate the tone. The remaining numbers in the "Ringback" header represent the cadence at which the tone is to be played. There must always be an even number of cadence parameters; clients receiving an odd number of cadence parameters are expected to ignore the "Ringback" header as malformed. The first cadence parameter is a decimal duration, in seconds, for which the tone is to be played. The second parameter is a duration, in seconds, which should be paused before playing the tone again. Third and subsequent parameters specify additional on/off periods for the tone. All ringtone patterns repeat. 2.2. Alternate Handling If no "Country" or "Ringback" header is present, clients implementing this extension may choose to make an intellegent guess about the called party's country. If the "180 Ringing" message contains a "Contact" header using a symbolic name (i.e. resolvable by DNS), the client takes note of the top-level-domain of this contact address for the processing described below. If the "Contact" header contains an IP address, the client may attempt to perform a DNS lookup on this IP address to determine the top-level-domain for its preferred name. If a top-level-domain could not be determined from the "Contact" header, the same series of steps is applied to the address in the "To" header. If a country-specific top-level-domain can be determined via the steps above, the client will play the ringtone matching this country (as if it had been specified in a "Country" header). Note that the country-specific top-level-domain "uk" should be treated the same as "gb." If a non-country-specific top-level-domain is determined, it is suggested that the client play one of: the ringback tone local to the calling party, North American ringback tone (see section 4.165. ), or a generic ringback tone meeting the requirements described in ITU-T E.180 [4] (e.g. 425 Hz at a cadence of 1 second on, 4 seconds off). It would be appropriate to allow the user to select between these three modes of operation to suit personal preferences. 3. Proxy Handling No special proxy handling is required by this extension. Roach [Page 4] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4. Ringtone Characteristics by Country This section provides a reference for relevant information about a number of countries. "Code" is the two-letter "country-code" token to be used in the "Country:" header. "Frequency" describes the frequency/frequencies which compose(s) the ringback tone, and the remaining information describes the cadence of the ringback tone. The two-letter country codes in this section are largely aligned which those published in ISO 3166 [3] , with some minor additions from the IANA document "Root-Zone Whois Information" [2] for practical considerations. The ringback tones and cadences are beleived to be the most common form of ringback tone in the associated country, as published in Suppliment 2 to ITU-T E.180 [5] . 4.1. Albania Code: al Frequency: 425 Hz - 1 second on - 4 seconds off 4.2. Algeria Code: dz Frequency: 25 Hz - 1.5 seconds on - 3.5 seconds off 4.3. Angola Code: ao Frequency: 25 Hz - 1 second on - 5 seconds off 4.4. Anguilla Code: ai Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.5. Antigua And Barbuda Code: ag Roach [Page 5] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Frequency: 440 Hz - 2 seconds on - 4 seconds off 4.6. Argentina Code: ar Frequency: 425 Hz - 1 second on - 4 seconds off 4.7. Aruba Code: aw Frequency: 425 Hz - 1 second on - 4 seconds off 4.8. Ascension Code: ac Frequency: 440 Hz - 1 second on - 3 seconds off 4.9. Australia Code: au Frequency: 400 Hz modulated with 17 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.10. Austria Code: at Frequency: 420 Hz - 1 second on - 5 seconds off 4.11. Bahamas Code: bs Frequency: 400 Hz - 2 seconds on - 4 seconds off 4.12. Bahrain Roach [Page 6] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Code: bh Frequency: 440 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.13. Barbados Code: bb Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.14. Belarus Code: by Frequency: 425 Hz - 0.8 seconds on - 3.2 seconds off 4.15. Belgium Code: be Frequency: 425 Hz - 1 second on - 3 seconds off 4.16. Benin Code: bj Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.17. Bermuda Code: bm Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.18. Bhutan Code: bt Frequency: 400 Hz + 25 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2.6 seconds off Roach [Page 7] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4.19. Botswana Code: bw Frequency: 400 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.20. Brazil Code: br Frequency: 425 Hz - 1 second on - 4 seconds off 4.21. British Indian Ocean Territory Code: io Frequency: 440 Hz - 1 second on - 3 seconds off 4.22. British Virgin Islands Code: vg Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.23. Brunei Darussalam Code: bn Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.3 seconds off - 0.4 seconds on - 2 seconds off 4.24. Bulgaria Code: bg Frequency: 425 Hz - 1 second on - 9 seconds off 4.25. Burkina Faso Code: bf Roach [Page 8] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Frequency: 425 Hz - 1 second on - 4 seconds off 4.26. Burundi Code: bi Frequency: 425 Hz - 1.7 seconds on - 3.3 seconds off 4.27. Cameroon Code: cm Frequency: 440 Hz - 1.7 seconds on - 3.3 seconds off 4.28. Canada Code: ca Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.29. Cayman Islands Code: ky Frequency: 425 Hz - 1 second on - 4 seconds off 4.30. Central African Rep. Code: cf Frequency: 425 Hz - 1.7 seconds on - 3.3 seconds off 4.31. Channel Islands: Jersey Code: je Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.32. Chile Roach [Page 9] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Code: cl Frequency: 400 Hz - 1 second on - 3 seconds off 4.33. China Code: cn Frequency: 450 Hz - 1 second on - 4 seconds off 4.34. Comoros Code: km Frequency: 425 Hz - 1.71 seconds on - 3.31 seconds off 4.35. Costa Rica Code: cr Frequency: 425 Hz - 1.2 seconds on - 4.6 seconds off 4.36. Cote D'Ivoire Code: ci Frequency: 50 Hz - 1.66 seconds on - 3.33 seconds off 4.37. Croatia Code: hr Frequency: 425 Hz - 1 second on - 4 seconds off 4.38. Cuba Code: cu Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.39. Cyprus Code: cy Roach [Page 10] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Frequency: 425 Hz - 1.5 seconds on - 3 seconds off 4.40. Czech Rep. Code: cz Frequency: 425 Hz - 1 second on - 4 seconds off 4.41. Denmark Code: dk Frequency: 425 Hz - 1 second on - 4 seconds off 4.42. Djibouti Code: dj Frequency: 425 Hz - 1.5 seconds on - 3.5 seconds off 4.43. Dominica Code: dm Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.44. Dominican Rep. Code: do Frequency: 400 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2.2 seconds off 4.45. Ecuador Code: ec Frequency: 425 Hz - 1.2 seconds on - 4.65 seconds off 4.46. Egypt Roach [Page 11] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Code: eg Frequency: 425 Hz modulated with 50 Hz - 2 seconds on - 1 second off 4.47. El Salvador Code: sv Frequency: 425 Hz - 1.2 seconds on - 5 seconds off 4.48. Estonia Code: ee Frequency: 425 Hz - 1 second on - 4 seconds off 4.49. Ethiopia Code: et Frequency: 425 Hz - 1 second on - 4 seconds off 4.50. Falkland Islands Code: fk Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off 4.51. Faroe Islands Code: fo Frequency: 425 Hz - 1 second on - 4 seconds off 4.52. Fiji Code: fj Frequency: 133 Hz modulated with 16 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.53. Finland Roach [Page 12] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Code: fi Frequency: 425 Hz - 1 second on - 4 seconds off 4.54. France Code: fr Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.55. French Polynesia Code: pf Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.56. Gabon Code: ga Frequency: 440 Hz - 1.5 seconds on - 3 seconds off 4.57. Gambia Code: gm Frequency: 425 Hz - 1 second on - 4 seconds off 4.58. Germany code: de Frequency: 425 Hz - 0.25 seconds on - 4 seconds off - 1 second on - 4 seconds off - 1 second on - 4 seconds off 4.59. Ghana Code: gh Frequency: 400 Hz - 1 second on Roach [Page 13] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 4 seconds off 4.60. Gibraltar Code: gi Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.61. Greece Code: gr Frequency: 425 Hz - 1 second on - 4 seconds off 4.62. Greenland Code: gl Frequency: 445 Hz - 1 second on - 4 seconds off 4.63. Grenada Code: gd Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.64. Guadeloupe Code: gp Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.65. Guiana Code: gf Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.66. Guinea Code: gn Frequency: 450 Hz Roach [Page 14] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 0.4 seconds on - 0.2 seconds off 4.67. Guyana Code: gy Frequency: 425 Hz - 1.75 seconds on - 3.25 seconds off 4.68. Honduras Code: hn Frequency: 440 Hz - 0.5 seconds on - 4 seconds off - 2 seconds on - 4 seconds off 4.69. Hongkong Code: hk Frequency: 440 Hz + 480 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 3 seconds off 4.70. Hungary Code: hu Frequency: 425 Hz - 1.2 seconds on - 3.7 seconds off 4.71. Iceland Code: is Frequency: 425 Hz - 1.2 seconds on - 4.7 seconds off 4.72. India Code: in Frequency: 400 Hz modulated with 25 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2.6 seconds off Roach [Page 15] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4.73. Indonesia Code: id Frequency: 425 Hz - 1 second on - 4 seconds off 4.74. Iran Code: ir Frequency: 425 Hz - 1 second on - 4 seconds off 4.75. Iraq Code: iq Frequency: 400 Hz - CONTINUOUS 4.76. Ireland Code: ie Frequency: 400 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.77. Israel Code: il Frequency: 400 Hz - 1 second on - 3 seconds off 4.78. Italy Code: it Frequency: 425 Hz - 1 second on - 4 seconds off 4.79. Jamaica Code: jm Frequency: 440 Hz modulated with 480 Hz - 2 seconds on - 4 seconds off Roach [Page 16] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4.80. Japan Code: jp Frequency: 400 Hz modulated with 16 Hz - 1 second on - 2 seconds off 4.81. Jordan Code: jo Frequency: 420 Hz modulated with 40 Hz - 1.2 seconds on - 4.8 seconds off 4.82. Kenya Code: ke Frequency: 425 Hz - 1 second on - 4 seconds off - 1 second on - 2 seconds off - 1 second on - 5 seconds off - 0.4 seconds on - 0.2 seconds off 4.83. Kiribati Code: ki Frequency: 425 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.84. Korea (Democratic People's Republic of) Code: kp Frequency: 440 Hz + 480 Hz - 1 second on - 2 seconds off 4.85. Korea (Republic of) Code: kr Frequency: 440 Hz + 480 Hz - 1 second on - 2 seconds off Roach [Page 17] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4.86. Kuwait Code: kw Frequency: 425 Hz - 1 second on - 4 seconds off 4.87. Kyrgyzstan Code: kg Frequency: 425 Hz - 0.8 seconds on - 3.2 seconds off 4.88. Lao Code: la Frequency: 425 Hz - 1 second on - 4 seconds off 4.89. Lebanon Code: lb Frequency: 435 Hz - 1.2 seconds on - 4.4 seconds off 4.90. Liberia Code: lr Frequency: 425 Hz - 1 second on - 4 seconds off 4.91. Lithuania Code: it Frequency: 425 Hz - 0.8 seconds on - 3.2 seconds off 4.92. Luxembourg Code: lu Frequency: 425 Hz - 1 second on - 4 seconds off Roach [Page 18] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4.93. Macau Code: mo Frequency: 425 Hz - 1 second on - 4 seconds off 4.94. Madagascar Code: mg Frequency: 25 Hz - 1.66 seconds on - 3.33 seconds off 4.95. Malawi Code: mw Frequency: 425 Hz - 1 second on - 4 seconds off 4.96. Malaysia Code: my Frequency: 425 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.97. Maldives Code: mv Frequency: 400 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.98. Mali Code: ml Frequency: 425 Hz - 1.7 seconds on - 3.3 seconds off 4.99. Malta Code: mt Frequency: 400 Hz + 450 Hz Roach [Page 19] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.100. Martinique Code: mq Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.101. Mauritania Code: mr Frequency: 425 Hz - 1.5 seconds on - 3.5 seconds off 4.102. Mauritius Code: mu Frequency: 425 Hz - 1 second on - 4 seconds off 4.103. Mayotte Code: yt Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.104. Mexico Code: mx Frequency: 425 Hz - 1 second on - 4 seconds off 4.105. Moldova Code: md Frequency: 425 Hz - 0.8 seconds on - 3.2 seconds off 4.106. Montserrat Code: ms Roach [Page 20] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.107. Morocco Code: mc Frequency: 425 Hz - 1.66 seconds on - 3.33 seconds off 4.108. Mozambique Code: mz Frequency: 400 Hz - 1 second on - 5 seconds off 4.109. Namibia Code: na Frequency: 400 Hz modulated with 33 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.110. Nauru Code: nr Frequency: 400 Hz - 1 second on - 4 seconds off 4.111. Nepal Code: np Frequency: 425 Hz - 1.1 seconds on - 3.1 seconds off 4.112. Netherlands Code: nl Frequency: 425 Hz - 1 second on - 4 seconds off 4.113. New Caledonia Roach [Page 21] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Code: nc Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.114. New Zealand Code: nz Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.115. Niger Code: ne Frequency: 440 Hz - 1.7 seconds on - 3.3 seconds off 4.116. Nigeria Code: ng Frequency: 400 Hz - 2 seconds on - 4 seconds off 4.117. Norway Code: no Frequency: 425 Hz - 1 second on - 4 seconds off 4.118. Oman Code: om Frequency: 425 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.119. Pakistan Code: pk Frequency: 450 Hz - 1 second on - 4 seconds off Roach [Page 22] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4.120. Panama Code: pa Frequency: 425 Hz - 1.2 seconds on - 4.65 seconds off 4.121. Papua New Guinea Code: pg Frequency: 425 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.122. Paraguay Code: py Frequency: 425 Hz - 1 second on - 4 seconds off 4.123. Philippines Code: ph Frequency: 450 Hz - 1 second on - 10 seconds off 4.124. Poland Code: pl Frequency: 425 Hz - 1 second on - 4 seconds off 4.125. Portugal Code: pt Frequency: 400 Hz - 1 second on - 5 seconds off 4.126. Qatar Code: qa Frequency: 400 Hz + 450 Hz - 0.4 seconds on Roach [Page 23] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 0.2 seconds off - 0.4 seconds on - 2.2 seconds off 4.127. Reunion Code: re Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.128. Romania Code: ro Frequency: 400 Hz modulated with 16 Hz - 2 seconds on - 4 seconds off 4.129. Russia Code: ru Frequency: 425 Hz - 0.8 seconds on - 3.2 seconds off 4.130. Rwanda Code: rw Frequency: 440 Hz - 1.7 seconds on - 3.3 seconds off 4.131. St Helena Code: sh Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off 4.132. St Kitts And Nevis Code: kn Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.133. St Lucia Code: lc Frequency: 425 Hz Roach [Page 24] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 0.375 seconds on - 0.25 seconds off - 0.375 seconds on - 2 seconds off 4.134. St Pierre And Miquelon Code: pm Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.135. St Vincent And The Grenadines Code: vc Frequency: 400 Hz + 450 Hz - 0.2 seconds on - 0.4 seconds off 4.136. San Marino Code: sm Frequency: 425 Hz - 1 second on - 4 seconds off 4.137. Sao Tome And Principe Code: st Frequency: 425 Hz - 1 second on - 5 seconds off 4.138. Saudi Arabia Code: sa Frequency: 425 Hz - 1.2 seconds on - 4.6 seconds off 4.139. Senegal Code: sn Frequency: 400 Hz - 1.7 seconds on - 3.3 seconds off 4.140. Seychelles Code: sc Roach [Page 25] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Frequency: 425 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.141. Sierra Leone Code: sl Frequency: 425 Hz - 1 second on - 4 seconds off 4.142. Singapore Code: sg Frequency: 425 Hz modulated with 24 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.143. Slovakia Code: sk Frequency: 425 Hz - 1 second on - 4 seconds off 4.144. Slovenia Code: si Frequency: 425 Hz - 1 second on - 4 seconds off 4.145. Solomon Code: sb Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off 4.146. South Africa Code: za Frequency: 400 Hz modulated with 33 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on Roach [Page 26] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 2 seconds off 4.147. Spain Code: es Frequency: 425 Hz - 1.5 seconds on - 3 seconds off 4.148. Sri Lanka Code: lk Frequency: 425 Hz - 0.4 seconds on - 0.2 seconds off 4.149. Suriname Code: sr Frequency: 425 Hz - 15 seconds on - 0.5 seconds off 4.150. Swaziland Code: sz Frequency: 400 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 4 seconds off 4.151. Sweden Code: se Frequency: 425 Hz - 1 second on - 5 seconds off 4.152. Switzerland Code: ch Frequency: 425 Hz - 1 second on - 4 seconds off 4.153. Syria Code: sy Frequency: 425 Hz Roach [Page 27] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 1 second on - 4 seconds off 4.154. Tajikistan Code: tj Frequency: 425 Hz - 0.8 seconds on - 3.2 seconds off 4.155. Tanzania Code: tz Frequency: 400 Hz - CONTINUOUS 4.156. Thailand Code: th Frequency: 400 Hz - 1 second on - 4 seconds off 4.157. Trinidad And Tobago Code: tt Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.158. Tunisia Code: tn Frequency: 425 Hz - 1.2 seconds on - 4.6 seconds off 4.159. Turkey Code: tr Frequency: 450 Hz - 2 seconds on - 4 seconds off 4.160. Turkmenistan Code: tm Frequency: 25 Hz - 0.4 seconds on - 4 seconds off Roach [Page 28] Internet Draft Ringback tones in SIP-Based Telephony November 2000 4.161. Turks And Caicos Islands Code: tc Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.162. Uganda Code: ug Frequency: 133 Hz + 17 Hz - 0.25 seconds on - 0.5 seconds off - 0.25 seconds on - 2 seconds off 4.163. United Arab Emirates Code: ae Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.164. United Kingdom Code: gb Frequency: 400 Hz + 450 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on - 2 seconds off 4.165. United States Code: us Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.166. United States Virgin Islands Code: vi Frequency: 440 Hz + 480 Hz - 2 seconds on - 4 seconds off 4.167. Uruguay Roach [Page 29] Internet Draft Ringback tones in SIP-Based Telephony November 2000 Code: uy Frequency: 425 Hz - 1 second on - 4 seconds off 4.168. Vanuatu Code: vu Frequency: 425 Hz - 1 second on - 4 seconds off 4.169. Wallis And Futuna Code: wf Frequency: 440 Hz - 1.5 seconds on - 3.5 seconds off 4.170. Western Samoa Code: ws Frequency: 425 Hz modulated with 25 Hz - 0.375 seconds on - 0.25 seconds off - 0.375 seconds on - 2 seconds off 4.171. Yugoslavia Code: yu Frequency: 450 Hz modulated with 25 Hz - 1 second on - 9 seconds off 4.172. Zambia Code: zm Frequency: 425 Hz - 1 second on - 4 seconds off 4.173. Zimbabwe Code: zw Frequency: 400 Hz modulated with 450 Hz - 0.4 seconds on - 0.2 seconds off - 0.4 seconds on Roach [Page 30] Internet Draft Ringback tones in SIP-Based Telephony November 2000 - 2 seconds off 5. Example Messages This section provides a collection of SIP messages which demonstrate the various uses of the "Country:" and "Ringback:" headers. 5.1. Dual-Tone Ringback This is an example of how a message might look for a standard two-tone ringback. In this example, both a country code of "us" and the standard US ringtone are specified. SIP/2.0 180 Ringing To: From: ;tag=012345 Call-ID: cmk2109fj@ws17.ericsson.se CSeq: 397 INVITE Via: SIP/2.0/UDP fw.ericsson.se Via: SIP/2.0/UDP ws17.ericsson.se Country: us Ringback: 440+480;2;4 Content-Length: 0 5.2. Modulated Ringback This is almost identical to the previous example, with the exception that Australian ringback is being provided. This demonstrates the syntax for modulated ringback tones. SIP/2.0 180 Ringing To: From: ;tag=34789a Call-ID: 13098jv@b04a24.ericsson.com CSeq: 32849 INVITE Via: SIP/2.0/UDP b04a24.ericsson.com Country: au Ringback: 400x17;0.4;0.2;0.4;2 Content-Length: 0 5.3. Continuous Ringtone Some localities provide an continuous ringtone, which indicates that there is no pause in the tone whatsoever. The suggested syntax for encoding such a ringtone is to provide an "off" period of 0. Roach [Page 31] Internet Draft Ringback tones in SIP-Based Telephony November 2000 SIP/2.0 180 Ringing To: From: ;tag=39835afe Call-ID: ckn9q23k@b04a24.ericsson.com CSeq: 3249786 INVITE Via: SIP/2.0/UDP b04a24.ericsson.com Country: tz Ringback: 400;1;0 Content-Length: 0 5.4. No "Ringback" specified This is an example of a message which specifies no particular ringtone pattern. If the calling party client understands the country code of "gb," it will provide the proper ringback tone; otherwise, it will provide default handling. SIP/2.0 180 Ringing To: From: ;tag=1987 Call-ID: 1358fjslk83la0@b04a24.ericsson.com CSeq: 985325 INVITE Via: SIP/2.0/UDP b04a24.ericsson.com Country: gb Content-Length: 0 5.5. Special PBX double-ring ringback This message gives an example in which the default ringtone for the country should be overridden (e.g. because the call has terminated on a PBX). The "Country" header is still provided so that clients not implementing the "Ringback" header can still provided a regionalised dialtone. SIP/2.0 180 Ringing To: From: ;tag=012345 Call-ID: cmk2109fj@ws17.ericsson.se CSeq: 397 INVITE Via: SIP/2.0/UDP fw.ericsson.se Via: SIP/2.0/UDP ws17.ericsson.se Country: us Ringback: 440+480;0.5;0.5;1;4 Content-Length: 0 5.6. Custom-defined ringback Roach [Page 32] Internet Draft Ringback tones in SIP-Based Telephony November 2000 This message gives an example in which the specific ringback tone has been provided, but no country. Clients not implementing the "Ringback" header will treat this as a normal "Ringing" message. SIP/2.0 180 Ringing To: From: ;tag=012345 Call-ID: cmk2109fj@ws17.ericsson.se CSeq: 397 INVITE Via: SIP/2.0/UDP fw.ericsson.se Via: SIP/2.0/UDP ws17.ericsson.se Ringback: 350;0.2;0.2;0.2;4 Content-Length: 0 6. References [1] M. Handley/H. Schulzrinne/E. Schooler/J. Rosenberg, "SIP: Session Initiation Protocol", RFC 2543, IETF; March 1999. [2] "Root-Zone Whois Information," http://www.iana.org/cctld/cctld-whois.htm, IANA. [3] "Codes for the Representation of Names of Countries," ISO 3166, ISO; 1993 [4] "Technical Characteristics of Tones for the Telephone Service," ITU-T E.180, ITU; 1993 [5] "Various Tones Used in National Networks," ITU-T E.180 Suppliment 2, ITU; January 1994 [6] J. Rosenberg/H. Schulzrinne, "Reliability of Provisional Responses in SIP," draft-ietf-sip-100rel-02.txt, IETF; June 2000. Work in progress. 7. Security Considerations Note that user location (including information as broad as "country") may be considered private information. As such, the user should have direct control over the presence and value of the "Country:" header. 8. Author's Address Adam Roach Ericsson Inc. Mailstop L-04 851 International Pkwy. Richardson, TX 75081 Roach [Page 33] Internet Draft Ringback tones in SIP-Based Telephony November 2000 USA Phone: +1 972-583-7594 Fax: 972-669-0154 E-Mail: adam.roach@ericsson.com Roach [Page 34]