1、 International Telecommunication Union ITU-T H.248.25TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2013) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Gateway control protocol: Basic CAS packages Recommendation ITU-T H.248.25 ITU-T
2、H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS H.100H.199 INFRASTRUCTURE OF AUDIOVISUAL SERVICES General H.200H.219 Transmission multiplexing and synchronization H.220H.229 Systems aspects H.230H.239 Communication procedures H.240H.259Coding o
3、f moving video H.260H.279 Related systems aspects H.280H.299 Systems and terminal equipment for audiovisual services H.300H.349 Directory services architecture for audiovisual and multimedia services H.350H.359 Quality of service architecture for audiovisual and multimedia services H.360H.369 Supple
4、mentary services for multimedia H.450H.499 MOBILITY AND COLLABORATION PROCEDURES Overview of Mobility and Collaboration, definitions, protocols and procedures H.500H.509 Mobility for H-Series multimedia systems and services H.510H.519 Mobile multimedia collaboration applications and services H.520H.
5、529 Security for mobile multimedia systems and services H.530H.539 Security for mobile multimedia collaboration applications and services H.540H.549 Mobility interworking procedures H.550H.559 Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAND, TRIPLE-PLAY AND ADVANCED MUL
6、TIMEDIA SERVICES Broadband multimedia services over VDSL H.610H.619 Advanced multimedia services and applications H.620H.629 Ubiquitous sensor network applications and Internet of Things H.640H.649 IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV General aspects H.700H.719 IPTV terminal devices H.
7、720H.729 IPTV middleware H.730H.739 IPTV application event handling H.740H.749 IPTV metadata H.750H.759 IPTV multimedia application frameworks H.760H.769 IPTV service discovery up to consumption H.770H.779 Digital Signage H.780H.789 For further details, please refer to the list of ITU-T Recommendati
8、ons. Rec. ITU-T H.248.25 (03/2013) i Recommendation ITU-T H.248.25 Gateway control protocol: Basic CAS packages Summary Recommendation ITU-T H.248.25 defines basic channel associated signalling (CAS) and R1 packages and supplemental CAS packages that, in association with the ITU-T H.248 Protocol, ca
9、n be used to control a media gateway (MG) from an external media gateway controller (MGC). This revision adds a new read-only property containing the current CAS state of the termination, to allow the MGC to resynchronize itself in the event it loses track of this state. This revision incorporates a
10、n update to the optionality of the “Pulse off“ and “Pulse On“ events. History Edition Recommendation Approval Study Group 1.0 ITU-T H.248.25 2003-07-14 16 1.1 ITU-T H.248.25 (2003) Cor. 1 2004-03-15 16 2.0 ITU-T H.248.25 2007-01-13 16 3.0 ITU-T H.248.25 2013-03-16 16 ii Rec. ITU-T H.248.25 (03/2013)
11、 FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for stu
12、dying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study gro
13、ups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with
14、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. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisi
15、ons (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of suc
16、h words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no positio
17、n 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, ITU had not received notice of intellectual property, protecte
18、d by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 All rights reserved. No part of t
19、his publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T H.248.25 (03/2013) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 1 4 Abbreviations and acronyms 1 5 Assumptions and partitioning . 2 6 Basic CAS package. 2 6.1 Pro
20、perties 2 6.2 Events . 3 6.3 Signals 5 6.4 Statistics 6 6.5 Procedures 7 7 Basic CAS addressing package 8 7.1 Properties 8 7.2 Events . 8 7.3 Signals 10 7.4 Statistics 11 7.5 Procedures 11 8 Robbed bit signalling package 11 8.1 Properties 11 8.2 Events . 12 8.3 Signals 14 8.4 Statistics 14 8.5 Proce
21、dures 14 9 Operator services and emergency services package . 14 9.1 Properties 15 9.2 Events . 15 9.3 Signals 15 9.4 Statistics 15 9.5 Procedures 15 10 Operator services extension package 15 10.1 Properties 16 10.2 Events . 16 10.3 Signals 17 10.4 Statistics 18 10.5 Procedures 19 iv Rec. ITU-T H.24
22、8.25 (03/2013) Page Appendix I Call flows . 20 I.1 Basic single-stage MF or DTMF wink start or immediate start . 20 I.2 EAOSS termination Telephone company operator services call 21 I.3 EAOSS termination IC/INC operator services call indirect through an access tandem (Overlap outpulsing) . 22 I.4 EA
23、OSS termination IC/INC operator services call indirect through an access tandem (No overlap outpulsing) 23 I.5 EAOSS termination IC/INC “National“ operator direct to the IC/INC (Overlap outpulsing) . 24 I.6 EAOSS termination IC/INC “National“ operator direct to the IC/INC (No overlap outpulsing) 24
24、I.7 EAOSS origination Telephone operating company serves the call . 25 Rec. ITU-T H.248.25 (03/2013) 1 Recommendation ITU-T H.248.25 Gateway control protocol: Basic CAS packages 1 Scope The basic channel associated signalling (CAS) package provides a baseline package. Basic CAS defines abstract even
25、ts and signals that are common to all CAS protocols. For some protocols, basic CAS provides all of the functionality required to satisfy the line interface, such as North American single-stage dialling applications or R1 signalling. For other protocols, basic CAS provides a baseline package for whic
26、h additional protocol specific extension packages can be defined. Further line signals and events required for international signalling protocols can be provided through extension packages. The basic CAS addressing package extends the basic CAS package to add the signals and events required for basi
27、c addressing. This would satisfy addressing functionality for many protocols such as North American single-stage dialling applications or R1 signalling. The robbed bit signalling (RBS) package, operator services and emergency services package and the operator services extension package can be used t
28、o provide functionality required in addition to the basic CAS package. The support of these packages is optional. 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
29、of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; 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 li
30、st of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T H.248.1 Recommendation ITU-T H.248.1 (2013), Gateway Control Protocol: Version 3. 3 Defini
31、tions None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: CAS Channel Associated Signalling MG Media Gateway MGC Media Gateway Controller RBS Robbed Bit Signalling TS Time Slot 2 Rec. ITU-T H.248.25 (03/2013) 5 Assumptions and partitioning The termin
32、ation the MGC addresses is the channel. With TS16, the MG associates the line signal with the appropriate channel. For some applications, the basic CAS package provides all of the functionality needed to satisfy the interface. In other cases (e.g., operator services), additional supplementary packag
33、es may be needed to meet the complete interface requirements. This Recommendation includes three supplementary packages which may be used to provide additional functionality required by some interfaces: The robbed bit signalling package provides basic RBS supervisory signalling that is required in a
34、ddition to the basic CAS package. The operator services and emergency services package provides supervisory signalling that is specific to North American operator services and emergency services. The operator services extension package provides supervisory signalling that is specific to North Americ
35、an operator services and is required in addition to the operator services and emergency services package. 6 Basic CAS package Package name: Basic CAS package Package ID: bcas (0x003f) Description: This package provides basic event and signal handling for terminations that support CAS signalling. Ver
36、sion: 2 Extends: None 6.1 Properties 6.1.1 CAS near-end line state Property name: CAS near-end line state Property ID: nels (0x0002) Description: Specifies the current CAS near-end line state of the termination by reflecting the last applied line signal. Type: Enumeration Possible values: Idle (0x01
37、) The CAS termination near-end is in the idle state Seize (0x02) The CAS termination near-end is in the seize state SeizeAck (0x03) The CAS termination near-end is in the seize acknowledge state Answer (0x04) The CAS termination near-end is in the answer state Default: The last applied line signal.
38、If no line signal has been applied by the MGC, Idle. Defined in: TerminationState Descriptor Characteristics: ReadOnly Rec. ITU-T H.248.25 (03/2013) 3 6.1.2 CAS far-end line state Property name: CAS far-end line state Property ID: fels (0x0003) Description: Specifies the current CAS far-end line sta
39、te of the termination by reflecting the last detected line event. Type: Enumeration Possible values: Idle (0x01) The CAS termination far-end is in the idle state Seize (0x02) The CAS termination far-end is in the seize state SeizeAck (0x03) The CAS termination far-end is in the seize acknowledge sta
40、te Answer (0x04) The CAS termination far-end is in the answer state Default: The last detected line event. If no line event has been detected by the MG, Idle. Defined In: TerminationState Descriptor Characteristics: ReadOnly 6.2 Events 6.2.1 Seizure Event name: Seizure Event ID: sz (0x0001) Descript
41、ion: Seizure event shall be reported when an incoming “Seizing“ signal occurs on the termination. The event is reported by the MG if either the timed transition to this line signal is detected or the line signal already exists. The line signal condition against which the “Seizing“ signal is verified
42、 is provisioned in the MG. 6.2.1.1 EventsDescriptor parameters None. 6.2.1.2 ObservedEventsDescriptor parameters None. 6.2.2 Seize acknowledge Event name: Seize acknowledge Event ID: sza (0x0002) Description: The Seize Acknowledge event shall be reported when an incoming “Seize Acknowledge“ signal o
43、ccurs on the termination. This event also acts as a start dial notification, indicating that out-pulsing should begin. For R1 interfaces, the event is reported when the “start dialling“/“proceed to send“ signal occurs. For wink start trunks, the “Seize Acknowledge“ event is reported when the trailin
44、g edge of the wink-start signal occurs. For immediate start trunks, the “Seize Acknowledge“ event is provided by the media gateway as an immediate response to the request for that event from the MGC. 4 Rec. ITU-T H.248.25 (03/2013) 6.2.2.1 EventsDescriptor parameters None. 6.2.2.2 ObservedEventsDesc
45、riptor parameters None. 6.2.3 Answer Event name: Answer Event ID: ans (0x0003) Description: The Answer event shall be reported when an incoming line signal “Answer“ occurs on the termination. The event is reported by the MG if either the timed transition to this line signal is detected or the line s
46、ignal already exists. The line signal condition against which the “Answer“ signal is verified is provisioned in the MG. 6.2.3.1 EventsDescriptor parameters None. 6.2.3.2 ObservedEventsDescriptor parameters None. 6.2.4 Idle Event name: Idle Event ID: idle (0x0004) Description: This event applies to a
47、n incoming interface and is reported when a “Clear“ or “Idle“ line signal occurs on the termination. For an R1 interface, the Idle event shall be reported when an “Idle“ line signal occurs on the termination. For robbed bit signalling digital interfaces, it corresponds to an “on-hook“ indication on
48、the termination. The event is reported by the MG if either the timed transition to this line signal is detected or the line signal already exists. The condition against which the signal is verified is provisioned in the MG. 6.2.4.1 EventsDescriptor parameters 6.2.4.1.1 Idle guard timing Parameter na
49、me: Idle guard timing Parameter ID: idlgt (0x0001) Description: Specifies whether the MG shall start an idle guard timer for the receipt of the “Idle“ signal. If the idle guard timer expires prior to the detection of idle signal and the CAS Failure event is active, the MG shall report a CAS Failure event with a “IDLTO“ error. The timer value is provisioned on the MG. Type: Boolean Optional: Yes Possible values: On when the idle guard timing is requested Off when the idle guard timing is turned off. Rec. ITU-T
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