Internet DRAFT - draft-itu-t-ieps-description
draft-itu-t-ieps-description
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)
<draft-itu-t-ieps-description-00.txt>
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
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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]
