Network Working Group ITU-T Internet Draft Geneva, Switzerland Expires August 20, 2001 February 20, 2001 Description of an international emergency preference scheme (IEPS) ITU-T Recommendation E.106 (Formerly CCITT Recommendation) Hal Folts Status of this Memo This document is an Internet-Draft and is NOT offered in accordance with Section 10 of RFC2026, and the author does not provide the IETF with any rights other than to publish as an Internet-Draft 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 beupdated, 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/lid-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Background Information The text of Recommendation E.106 of the International Telecommunication Union, Telecommunication Standardization Sector (ITU-T) is being posted as an Internet -Draft with permission of the Director, ITU Telecommunication Standardization Bureau (TSB). Recommendation E.106 is being provided as background information to facilitate work in the IETF on IEPS matters as part of the cooperation between the ITU-T and IETF. Although Recommendation E.106 describes provisions for emergency communications in the Public Switched Telephone Network (PSTN) and the Integrated Services Digital Network (ISDN), it is recognized that with the emergence of Internet- based telecommunication services provisions for similar and enhanced emergency communications need to be developed for next generation networks. In this regard, ITU-T Study Group 16 is developing a new Recommendation for International Emergency Multimedia Service (IEMS) as an extension to E.106 to provide for enhanced emergency services over Internet-based networks in the future. Related Internet-Drafts on IEPS that have been posted are the following: draft-folts-ohno-ieps-considerations-00.txt draft-carlberg-ieps-framework-00.txt The verbatim text of ITU-T Recommendation E.106 converted to the Internet-Draft format follows. ITU-T Recommendation E.106 [Page 1] Internet Draft Description of IEPS February 17, 2001 Summary The International Emergency Preference Scheme (IEPS) is needed when there is a crisis situation which causes abnormal telecommunication requirements for governmental, military, civil authorities and other essential users of public telecommunications networks. It allows authorized users to have access to the International Telephone Service while the service is restricted due to damage, congestion and/or other faults. Source ITU-T Recommendation E.106 was prepared by ITU-T Study Group 2 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on 13 March 2000. FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. Copyright ITU 2000 All rights reserved. No part of this publication may be reproduced or utilized ITU-T Recommendation E.106 [Page 2] Internet Draft Description of IEPS February 17, 2001 In any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. Introduction In a crisis situation, there is a need for telecommunications among Governmental military, civil authorities and other essential users of public telecommunications networks, such as the PSTN, ISDN and PLMN. These communications, which are regarded as essential, will be needed at the same time as the public will be attempting to make more calls while the telecommunications service may be restricted due to damage, congestion and/or faults. Most countries have national preference schemes to allow this essential internal traffic to flow. However, it is important for an international support scheme during a crisis to lay down the interoperability principles necessary to allow communications between the essential users in one country and their correspondents in another. The International Emergency Preference Scheme (IEPS) will subsequently derive from these principles as a whole. Recommendation E.106 Description of an International Emergency Preference Scheme (IEPS) (Geneva, 2000) 1 Scope The International Emergency Preference Scheme (IEPS) allows authorized users to have access to the International Telephone Service as described in Recommendation E.105 [1] while the service is restricted due to damage, congestion and/or other faults. This Recommendation describes the functional requirements, features, access and the operational management of the IEPS. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. [1] ITU-T Recommendation E.105 (1992), International telephone service. 3 Definitions This Recommendation defines the following term: 3.1 IEPS user: User determined by national governments to have access to IEPS. ITU-T Recommendation E.106 [Page 3] Internet Draft Description of IEPS February 17, 2001 4 Abbreviations This Recommendation uses the following abbreviations: IEPS International Emergency Preference Scheme ISDN Integrated Services Digital Network PLMN Public Land Mobile Network PSTN Public Switched Telephone Network 5 Overall functional requirements The primary goal of IEPS is to support crisis management arrangements. IEPS should significantly increase the ability of essential users to initiate and complete their communications (voice and data) via the PSTN, ISDN and PLMN. Most existing national preference schemes are designed to be invoked in times of national crisis, but there could be occasions when international preference may need to be enabled although activating the respective national system would be unnecessary. An example of this is when intense international traffic is generated to a distant country in crisis. Therefore, international and national preference schemes would need to be considered as independent and yet be compatible. Authorized users of a national preference scheme may not be eligible to gain access to the international scheme, but authorized users of the international scheme must be able to use their own national preference scheme. It should be recognized that in some national systems, IEPS features may be permanently enabled. IEPS users should be able to use their normal telecommunications equipment in times of crisis. When making an IEPS call, the PSTN/ISDN must not appear markedly different to any essential user. Calls originated by IEPS users should be given priority through the networks involved when IEPS is enabled. Under conditions of severe damage or congestion, countries should be able to effect control, particularly over incoming traffic, even though IEPS may have been invoked. To ensure that a preference user can reliably call any other user, call- barring or similar facilities which can be set by or for any called party should be overridden. There must be no conflict between preference for a call from an essential user and call priority for a non-essential user to an emergency service. The national authority will need to determine the preference status of calls from essential users from countries with which agreements have been made. It is likely that call restrictions to certain specific destinations (e.g. country codes, area codes) will already be in place when IEPS is activated. Such restrictions should not apply to IEPS users. The remaining destinations should continue to be available to non-IEPS users. ITU-T Recommendation E.106 [Page 4] Internet Draft Description of IEPS February 17, 2001 Both the technical means and the management procedures for the initiation and operation of IEPS should be established and should be compatible with the existing national network traffic management schemes. Priority calls to a number where there has been a call transfer or call forwarding will retain the priority. The marking will need to pass from one telecommunications provider to the other. 6 IEPS features Calls from IEPS users should be suitably marked (see Note 1) at the network entrance and such markings should be associated with the call to completion (i.e. IEPS calls should be marked from end to end). NOTE 1 - Call Marking: A specific identifying mark is associated with the call which prompts operational elements of the public switched network to provide advantages in signalling, switching and traffic routing over non-marked calls. Call marking facilities are available in modern signalling networks and these can be used by the telecommunications providers to maintain services to other users while allowing call completion advantages to preference user's calls. NOTE 2 - The call marking, marking interpretation and the processing arrangements will have to be specified and fully agreed at the gateway points. Specific arrangements to transfer the marked signals would also need to be agreed with non-participating but intermediate transit countries. The essential network features for the successful operation of IEPS are: a) priority dial tone; b) priority call setup, including priority queuing schemes; and c) exemption from restrictive management controls, such as call gapping. A list of features that will enhance call completion are mentioned in Annex A. All IEPS calls will be of the same call class such that there will be only one level of priority for IEPS calls. Pre-emption in the Public Network (i.e. terminating any existing call) is not to be provided. 7 Access to the IEPS A user of any other network than the PSTN/ISDN requiring access to IEPS will need to ensure that IEPS call marking information can be carried across the network being used. Options to access IEPS are: - access via predetermined lines (the most practical option in nations using Access Control schemes). This option reduces the possible misuse of the enhanced facility; NOTE - Access Control: If sufficient resources are no longer available, the ability to make telephone calls is removed from non-preference users, ITU-T Recommendation E.106 [Page 5] Internet Draft Description of IEPS February 17, 2001 usually indicated by an absence of dial tone. The ability to receive calls is not affected. All calls then made by an essential user are permitted. Access control can be applied in either analogue or digital networks. - access by means of special code including for example a Personal Identification Number (PIN) at any available PSTN/ISDN interface, which may be confined to the network of any particular telecommunications operator. This option provides the flexibility of access at the cost of technological and operational considerations. The allocation and control of the IEPS user PINs would require the establishment of appropriate procedures; and - access to/from any national emergency networks. 8 Operational management of the IEPS Requests for enabling the IEPS should be co-ordinated between the involved countries. In each country IEPS will be authorized by the national authority and it will be their responsibility to establish the necessary arrangements. IEPS users are to be determined by national governments. Some criteria for the selection of IEPS user can be found in Appendix I. ANNEX A Features and techniques to enhance call completion The features described in this annex may be used separately or in combination to create favourable conditions for the successful completion of calls, but IEPS is not necessarily dependent on them. The list is not exclusive and the use of these features is to be determined by each country, taking into account the capabilities of the networks being used. ================================================================================ No. Essential features for IEPS Feature requires call marking ================================================================================ 1 Priority dial tone - wireline or wireless No connections (Essential Line Service) -------------------------------------------------------------------------------- 2 Priority call setup message through signalling Yes network with high priority call identifier (HPC identifier) -------------------------------------------------------------------------------- 3 Exemption from restrictive (network) management Yes controls, such as call gapping (Exemption from RNMC) -------------------------------------------------------------------------------- ITU-T Recommendation E.106 [Page 6] Internet Draft Description of IEPS February 17, 2001 ================================================================================ No. Optional features (F) and techniques (T) to Feature enhance call completion requires call marking ================================================================================ 4 Survivable access and egress from end user location to PSTN/ISDN: (F) a) Local exchange bypass; (T) b) Diverse PSTN/ISDN access from cellular; (T) c) Prescription override; (T) d) Avoidance routing; (T) e) Diverse routing. (T) -------------------------------------------------------------------------------- 5 IEPS user verification (F) Yes -------------------------------------------------------------------------------- 6 Special announcements on call progress (F) Yes -------------------------------------------------------------------------------- 7 Special routing capabilities: (F) a) Enhanced alternate routing; (T) Yes b) Trunk queuing; (T) Yes c) Off-hook trunk waiting; (T) Yes d) Dynamic trunk reservation; (T) Yes e) Trunk sub-grouping; (T) Yes f) Automatic call re-routing; (T) No g) PSTN/ISDN partitioning. (T) No -------------------------------------------------------------------------------- 8 Call forwarding (F) Yes -------------------------------------------------------------------------------- 9 Abbreviated dialling (F) No -------------------------------------------------------------------------------- 10 Attendant override (F) Yes -------------------------------------------------------------------------------- 11 Authorization codes (F) No -------------------------------------------------------------------------------- 12 Automatic call distribution (F) No -------------------------------------------------------------------------------- 13 Call-by-call service selection (F) No -------------------------------------------------------------------------------- 14 Call pickup (F) No -------------------------------------------------------------------------------- 15 Call transfer (F) No -------------------------------------------------------------------------------- 16 Call waiting (F) No -------------------------------------------------------------------------------- 17 Calling number identification (F) No ================================================================================ A.1 Priority Dial Tone A service arrangement that enhances the ability of IEPS users to receive priority over other users for the reception of dial tone. This is a restrictive treatment of non-IEPS users. Note that access denial systems are an extreme form of restrictive treatment, providing dial tone to permitted lines only. Call ITU-T Recommendation E.106 [Page 7] Internet Draft Description of IEPS February 17, 2001 attempts from such designated lines are placed in a priority queue and are handled before non-IEPS calls. A.2 Priority call setup message through national and international signalling network with call identifier This is a method of marking and identifying IEPS calls through networks. As the IEPS call progresses through the networks, this identifier would enable special routing and preferential treatment to ensure the higher probability of call completion. A.3 Exemption from restrictive management controls A set of control measures used to prevent or control degradation of network service. These measures are either expansive or protective. Expansive measures increase call routing choices by providing more capability than normal to carry excess traffic. Protective measures limit calls going into a switch or trunk group. A.4 Survivable access and egress from end user location to PSTN/ISDN Techniques that enhance survivable access from the end user to the PSTN/ISDN are described in a) to e). a) Local exchange bypass The use of direct access services to or egress services from Switched Networks by using either bulk, wide-band, switched, point-to-point, or circuit- by-circuit services. These services are available from providers such as cellular service providers, specialized service providers and satellite service providers. b) Diverse PSTN/ISDN access from cellular This technique allows cellular networks to directly interconnect with other elements of PSTN/ISDN. This allows cellular calls to be routed around failed or congested nodes. Network access diversity allows specifically identified calls to be routed to private or special purpose networks. c) Prescription override The ability to select an alternative carrier, e.g. by dialling a specific code or operating a selection key on the terminal instrument. d) Avoidance routing This technique, with limited availability, permits a user to enhance their survivability in PSTN/ISDN by directing the service provider to assign them to transmission facilities that avoid points of vulnerability such as earthquake zones or hurricane areas. ITU-T Recommendation E.106 [Page 8] Internet Draft Description of IEPS February 17, 2001 e) Diverse routing This technique provides the user with a second route over physically separate facilities which can be used if the primary route is unavailable. A.5 IEPS user verification This feature allows for the verification of the IEPS user. Personal Identification Numbers (PINs), line identification, authorization codes or call- back facilities could be used to verify the call as an authorized IEPS call. A.6 Special announcements on call progress This feature will provide recorded voice announcements for originated call to announce information to the user when calls cannot be completed or to provide problem and restoral information. A.7 Special routing capabilities Special routing capabilities that enhance call completion are described in a) to g). a) Enhanced alternate routing Routing programs are used to provide special routing controls and paths within a network. b) Trunk queuing This technique would hold the IEPS call in queue until a trunk became available, then the first call in queue (the IEPS call) would have access to the next available trunk. The IEPS call would not receive an immediate "all trunks busy" tone. c) Off-hook trunk waiting This technique allows the IEPS caller to remain off-hook and the network continually searches, at predetermined intervals (i.e. several seconds) for an idle trunk if no idle trunk was found on the initial attempt. d) Dynamic trunk reservation This technique automatically reserves reservation of trunks for certain classes of calls under designated conditions. It could be implemented or activated in the following ways: IEPS calls could be allocated a variable number of trunks between switches according to demand; the use of network management control under predetermined conditions, to reserve trunks in an idle condition for the exclusive use of IEPS calls; and the designation of specific sub-groups within a trunk group that, under predetermined conditions, would be reserved for IEPS calls. ITU-T Recommendation E.106 [Page 9] Internet Draft Description of IEPS February 17, 2001 e) Trunk sub-grouping This technique splits trunks into pre-assigned sub-groups; one for general use and another for IEPS use only. Under normal conditions general use traffic could use either sub-group. During emergencies only IEPS calls would use the IEPS sub- group. Overflow from the IEPS sub-group could be routed over the general use sub-group but the general calls would not be allowed to overflow to the IEPS sub-group. f) Automatic call re-routing This technique allow calls to be routed over other operator's networks. g) PSTN/ISDN partitioning This is the use of hardware or software to separate traffic into specific functional groups for the purpose of providing special service capabilities such as enhanced call completion for IEPS calls. A.8 Call forwarding A feature that enables calls to be re-routed automatically from one line to another or to an attendant. A.9 Abbreviated dialing A feature by which a user can attempt a call by dialling a two- or three- digit code that instructs a database to obtain the actual desired number from a look- up table and transmit it into the network to connect the calling line to the called line. A.10 Attendant override A feature that allows the terminal equipment operator to interrupt a call that is in progress. A.11 Authorization codes Unique multi-digit codes used to allow an authorized user privileged access to a network, system or device. If the code is validated the call is allowed to advance. A.12 Automatic call distribution A system designed to evenly distribute traffic by directing incoming calls over a group of terminals. A.13 Call-by-call service selection A feature that provides improved trunking efficiency between end-user location and end-office by allowing a variety of services to use the same trunk group and by distributing traffic over the total number of available trunks on a call-by- call basis. ITU-T Recommendation E.106 [Page 10] Internet Draft Description of IEPS February 17, 2001 A.14 Call pickup A feature that enables a connected extension to answer any ringing extension within an assigned call pickup group. A.15 Call transfer A feature whereby a call to a user's number is automatically transferred to one or more alternative numbers when the called number is busy or does not answer. A.16 Call waiting A feature that provides a distinctive audible tone to a busy user's line to notify the user when another caller is attempting to reach his/her number. A.17 Calling number identification A feature that provides the identification of the calling user's number by means of a visual or audible identification at the called terminal. APPENDIX I Criteria for the selection of IEPS users IEPS users are to be determined by national governments. The criteria for selection may be as follows: military purposes; civil defence/"home defence", e.g. public warning systems; diplomatic and other vital governmental purposes; state security purposes including customs and immigration; emergency services by local authorities, including police, fire services, etc.; posts and telecommunications service providers, for maintaining their service provision to other essential users; public utilities including energy, water supplies, etc.; medical services; air and sea rescue. END OF RECOMMENDATION E.106 ------------------------------------------------- Email list and Web Site An Email list has been established for discussion of the IEPS issues - ieps@listserv.gsfc.nasa.gov, to subscribe send Email to majordomo@listserv.gsfc.nasa.gov indicating: subscribe ieps - in ITU-T Recommendation E.106 [Page 11 Internet Draft Description of IEPS February 17, 2001 the body (do not include any other text in the body). The Web Site at http://www.iepscheme.net provides background and access to working documents. Contact Hal Folts National Communications System 701 Arlington South Court House Rd. Arlington VA 22204-2198 foltsh@ncs.gov ITU-T Recommendation E.106 [Page 12]