1、 International Telecommunication Union ITU-T H.248.22TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2013) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Gateway control protocol: Shared Risk Group package Recommendation ITU-T H.248.22
2、 ITU-T 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.259C
3、oding of 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
4、 Supplementary 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
5、H.520H.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 ADVAN
6、CED MULTIMEDIA 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 dev
7、ices H.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 Recom
8、mendations. Rec. ITU-T H.248.22 (03/2013) i Recommendation ITU-T H.248.22 Gateway control protocol: Shared Risk Group package Summary Recommendation ITU-T H.248.22 describes a package to enable the media gateway controller (MGC) to indicate to the media gateway (MG) to use or not to use network reso
9、urces associated with a shared risk group when setting up connections. When network connections are associated with ephemeral terminations in the MG, certain resources are used. A failure in the MG may result in the loss of certain groups of resources, whilst other groups of resources remain unaffec
10、ted. The resources that share a risk of failure are called a shared risk group. A shared risk group is simply a grouping of the network resources (e.g., IP interfaces) sharing the same risk of failure. Each shared risk group could, for example, contain a number of IP interfaces located on the same p
11、iece of hardware. If a resource failure occurs, only terminations in the shared risk group corresponding to the failed resource are affected while other terminations are not. This revision incorporates corrections to several values in the procedure associated with the usage of the Include shared ris
12、k group property. History Edition Recommendation Approval Study Group 1.0 ITU-T H.248.22 2003-07-14 16 2.0 ITU-T H.248.22 2013-03-16 16 ii Rec. ITU-T H.248.22 (03/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunication
13、s, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications
14、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 groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid
15、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 ISO and IEC. NOTE In this Recommendation, the expression Administration is used for conciseness to indicate both a telecommunication
16、 administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandator
17、y 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 such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attentio
18、n to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others ou
19、tside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the
20、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 this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T H.248.22 (03/2013) iii
21、 Table of Contents Page 1 Scope 1 2 References. 3 3 Definitions 3 4 Abbreviations and acronyms 3 5 Shared risk group package 3 5.1 Properties 3 5.2 Events . 4 5.3 Signals 4 5.4 Statistics 4 5.5 Procedures 4 Rec. ITU-T H.248.22 (03/2013) 1 Recommendation ITU-T H.248.22 Gateway control protocol: Share
22、d Risk Group package 1 Scope When network connections are associated with ephemeral terminations in the MG, certain resources are used. A failure in the MG may result in the loss of certain groups of resources, whilst other groups of resources remain unaffected. The resources that share a risk of fa
23、ilure are called a shared risk group. A shared risk group is simply a grouping of the network resources (e.g., IP interfaces) sharing the same risk of failure. Each shared risk group could, for example, contain a number of IP interfaces located on the same piece of hardware. If a resource failure oc
24、curs, only terminations in the shared risk group corresponding to the failed resource are affected while other terminations are not. The MGC may select different shared risk groups when the redundancy of network resources has to be controlled, or when the MGC wishes to specify which group of resourc
25、es are to be used. With this functionality the MGC is given control of the resources used by ephemeral terminations in the MG. The MGC may order the MG to use resources from a selected Shared Risk Group, or not to use resources from a Shared Risk Group. This gives an advantage over using Termination
26、 ID schemes to link resource groups in that the MGC can specify certain resources to avoid in a CHOOSE ($) Termination ID scenario. The capability to order the MG to use diverse resources for different connections is particularly useful when a pair of connections is used for a primary and secondary
27、link e.g., for signalling transport. Figure 1 shows an example of a scenario where two shared risk groups have been defined and are used by ephemeral terminations. Context 3 represents a Primary Link and Context 5 is its secondary link. 2 Rec. ITU-T H.248.22 (03/2013) H.248.22_F01Termination 1RTP st
28、reamTermination 2RTP streamInterface board 1Termination 7Termination 8Context 1 Context 2Termination 3RTP streamTermination 4RTP streamSRGI 1Termination 9Termination 10Context 3Context 4Termination 5RTP streamTermination 6RTP streamSRGI 2Termination 11Termination 12Context 5Context 6Media gateway SC
29、N bearerchannelSCN bearerchannelSCN bearerchannelSCN bearerchannelSCN bearerchannelSCN bearerchannelInterface board 2Interface board 3Figure 1 Example of shared risk group usage The Shared Risk Group Package may be used whenever the behaviour described in the procedures section of the package is req
30、uired. Rec. ITU-T H.248.22 (03/2013) 3 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
31、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 list of the currently valid ITU-T Recommendations is regularly published. The
32、 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 Definitions This Recommendation defines the following term: 3.1 shared risk group
33、: A Shared Risk Group consists of resources or groups of resources that share the same risk of failure. It is the relationship between resources in a MG that defines a shared risk group. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: DSP Digital Signa
34、l Processor MG Media Gateway MGC Media Gateway Controller RTP Real Time Protocol SCN Switched Circuit Network SRGI Shared Risk Group Identity 5 Shared risk group package Package name: Shared Risk Group Package Package ID: shrisk (0x006b) Description: This package defines properties and procedures th
35、at are used to distinguish between different shared risk groups in the MG. Version: 1 Designed to be extended only: No Extends: None 5.1 Properties 5.1.1 Include shared risk group Property name: Include shared risk group Property ID: incl (0x0001) Description: The value of this property indicates if
36、 the shared risk group specified is requested to be used or to not be used (see clause 5.5.1.1 for further details). 4 Rec. ITU-T H.248.22 (03/2013) Type: Sublist of type Boolean Possible values: on (TRUE) Use resources from the specified SRGI only Default off (FALSE) Use resources from any but the
37、specified SRGI Defined in: Termination State Descriptor Characteristics: Write Only 5.1.2 Shared risk group identity request Property name: Shared risk group identity request Property ID: srgir (0x0002) Description: The value of this property specifies the shared risk group identity Type: Sublist of
38、 type Integer Possible Values: The values specify the SRGI according to a scheme understood by both MGC and MG (see clause 5.5.1.3 for further details). Defined in: Termination State Descriptor Characteristics: Write Only 5.1.3 Assigned shared risk group identity Property name: Assigned shared risk
39、group identity Property ID: asrgi (0x0003) Description: The value of this property specifies the Shared risk group identity that has been allocated by the MG. This value cannot be directly modified by the MGC. Type: Integer Possible Values: The values specify the SRGI according to a scheme understoo
40、d by both MGC and MG (see clause 5.5.1.2 for further details). Defined in: Termination State Descriptor Characteristics: ReadOnly 5.2 Events N/A 5.3 Signals N/A 5.4 Statistics N/A 5.5 Procedures 5.5.1 Establishment/modification of terminations when using shared risk group When an MGC determines that
41、 an ephemeral termination must use resources belonging to (or different to) a specific shared risk group, an Add/Modify/Move command will be sent to the MG specifying the Include shared risk group property and the Shared risk group identity Request property. Rec. ITU-T H.248.22 (03/2013) 5 5.5.1.1 U
42、sage of the Include shared risk group property The Include shared risk group property shall be used to indicate to the MG if resources from the specified shared risk group identity (shrisk/srgir) must be used for the termination (shrisk/incl = on) or if resources from the specified risk group identi
43、ty must not be used for the termination (shrisk/incl = off). If the MGC is not concerned with which shared risk groups are used then it should not include the shrisk/incl nor shrisk/srgir properties. The shrisk/incl and shrisk/srgir properties are valid only for the command that they are contained i
44、n. They cannot be read/audited after the execution of the command. Wildcarding values with CHOOSE ($) or ALL (*) shall not be used with shrisk/incl and/or shrisk/srgir. For example: in the case of a semi-permanent connection and a protective secondary link, by specifying (shrisk/incl = on, shrisk/sr
45、gir = 1) for the primary link and (shrisk/incl = off, shrisk/srgir = 1) for the secondary, the MGC is assured that the primary and secondary links are not sharing the same groups of resources. The MGC may provide a sublist of shrisk/incl and shrisk/srgir to the MG to enable the MGC to request that c
46、ertain shared risk groups shall be used and other shared risk groups shall not be used. The first value of shrisk/incl in the sublist corresponds to the first value of shrisk/srgir sublist. 5.5.1.2 Usage of the Assigned shared risk group identity property The Assigned Shared Risk Group Identity (shr
47、isk/asrgi) contains the accumulated shared risk identities of the resources used by the termination. This value cannot be directly written by the MGC. However, it can indirectly be influenced by adding, modifying or subtracting resources from the termination. The MGC can audit this property to deter
48、mine the shared risk groups used by a termination. 5.5.1.3 Usage of the Shared risk group identity property How the Shared risk group identity is associated with MG resources is out of the scope of this Recommendation. The different resources used by a termination may have different Shared Risk Grou
49、p Identity ranges. However, it is assumed that this will be operator configurable and provisioned on both the MGC and MG so that they have a mutual understanding of the Specified Risk Group identity schema. For example, a binary structure of the property can be used. That is, the shrisk/srgi decimal integer is treated as a four byte binary number within the MG and MGC. This way different bytes or groups of bits may be used to address different types of resources in the MG. For example:
