1、 International Telecommunication Union ITU-T Series HTELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 11(02/2009) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSAnalysis of class-based home network QoS solutions ITU-T H-series Recommendations Supplement 11 ITU-T H-SERIES RECOMMENDATIONS AUDIO
2、VISUAL 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.259 Coding of moving video H.260H.279 Rel
3、ated 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 Supplementary services for multimed
4、ia 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.529 Security for mobile multi
5、media 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 MULTIMEDIA SERVICES Broadband mu
6、ltimedia services over VDSL H.610H.619 Advanced multimedia services and applications H.620H.629 IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV General aspects H.700H.719 IPTV terminal devices H.720H.729 IPTV middleware H.730H.739 IPTV application event handling H.740H.749 IPTV metadata H.750H.75
7、9 IPTV multimedia application frameworks H.760H.769 IPTV service discovery up to consumption H.770H.779 For further details, please refer to the list of ITU-T Recommendations. H series Supplement 11 (02/2009) i Supplement 11 to ITU-T H-series Recommendations Analysis of class-based home network QoS
8、solutions Summary Supplement 11 to ITU-T H-series Recommendations provides the gap analysis of class-based home network QoS solutions. Specifically, five documents in relevant SDOs which contain provisions of home network QoS solutions are analysed. Some aspects of class-based QoS solutions such as
9、the number of classes and practices of DiffServ code point (DSCP) are compared and summarized. In addition, this supplement identifies some issues that need to be considered in future Recommendations. Source Supplement 11 to ITU-T H-series Recommendations was agreed on 6 February 2009 by ITU-T Study
10、 Group 16 (2009-2012). Keywords Class-based QoS, DSCP, home network. ii H series Supplement 11 (02/2009) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Te
11、lecommunication 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 on a worldwide basis. The World Telecommunication Standardizatio
12、n 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 down in WTSA Resolution 1. In some areas of information technolo
13、gy which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this publication, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance wit
14、h this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the publication is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language su
15、ch as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the publication is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this publicatio
16、n 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 outside of the publication development process. As of the date of approval of th
17、is publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database
18、at http:/www.itu.int/ITU-T/ipr/. ITU 2009 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. H series Supplement 11 (02/2009) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 4 Abbreviations and acronym
19、s 2 5 Framework for home network QoS 2 6 Comparison and issues . 4 6.1 Comparison of existing practices . 4 6.2 Observations and issues for future study 7 7 Approaches for future Recommendations 9 7.1 Single policy. 9 7.2 Segmentation 9 7.3 Dynamic configuration. 10 iv H series Supplement 11 (02/200
20、9) Introduction There are two types of QoS mechanisms, i.e., class-based and session-based QoS mechanisms, used in the home network. The class-based QoS mechanism has an advantage of simplicity; however, it does not guarantee the level of QoS unlike the session-based QoS scheme. In a typical class-b
21、ased QoS mechanism, each IP packet is classified into a small number of classes which are typically 4-8, and its priority is identified by QoS marking using a certain value, e.g., DSCP. Each network device uses this marking information within the IP packet to find its relative priority and handles t
22、he packet according to the priority. An important issue on the class-based scheme is that all devices including bridging and terminal devices need to comply with the single policy. Without having a well-coordinated single policy, the integrity of QoS will be lost. This means that such network is not
23、 different from the “best-effort network“ because packets cannot be treated differently based on the priority. This nature of class-based QoS mechanism raises a challenge for standardization. There are some documents which include the description of QoS marking, and consistency among these documents
24、 needs to be checked. Furthermore, it may not be enough even if all the home network documents are completely consistent. The home network is typically connected to the access network through UNI that is defined by each telecom carrier. As mentioned in ITU-T H.622, the home network has two roles: ex
25、tension of access network and interconnection between home network devices. In ITU-T H.622, the former case is called the primary domain, while the latter case is called the secondary domain. It is possible and likely that the both domains will overlap physically, particularly in case of the IP-base
26、d home network. This means that the traffic complying with the access network specification can compete for the network resources with the traffic complying with the different home network specification. Inconsistency between the home network and the access network specifications may undermine the t
27、ransmission quality. H series Supplement 11 (02/2009) 1 Supplement 11 to ITU-T H-series Recommendations Analysis of class-based home network QoS solutions 1 Scope This supplement provides the gap analysis of the class-based home network QoS solutions. The purpose of this supplement is to clarify the
28、 problems which will result in not having well-harmonized QoS solutions in the home network, but this supplement does not intend to provide any requirements for implementation or any preferred documents/solutions analysed in this supplement. In addition, this supplement focuses on the use of DSCP, p
29、articularly in association with applications. The information indicated in this supplement may be useful for future work, including development of new Recommendations. 2 References ITU-T G.1010 Recommendation ITU-T G.1010 (2001), End-user multimedia QoS categories. ITU-T H.622 Recommendation ITU-T H
30、.622 (2008), A generic home network architecture with support for multimedia services. ITU-T Y.1221 Recommendation ITU-T Y.1221 (2002), Traffic control and congestion control in IP-based networks. ITU-T Y.1541 Recommendation ITU-T Y.1541 (2006), Network performance objectives for IP-based services.
31、IEEE 802.1D IEEE 802.1D (2004), IEEE Standard for Local and metropolitan area networks Media Access Control (MAC) Bridges. IEEE 802.11 IEEE 802.11 (2007), IEEE Standard for information technology Telecommunications and information exchange between systems Local and metropolitan area networks Specifi
32、c requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. DSL-F TR-098 DSL Forum TR-098 Amendment 2 (2008), Internet Gateway Device Data Model for TR-069. DSL-F TR-101 DSL Forum TR-101 (2006), Migration to Ethernet-Based DSL Aggregation. DSL-F TR-124 D
33、SL Forum TR-124 (2006), Functional Requirements for Broadband Residential Gateway Devices. DSL-F TR-133 DSL Forum TR-133 (2005), DSLHome TR-064 Extensions for Service Differentiation. DLNA IEC 62481-1 (2007), Digital living network alliance (DLNA) home networked device interoperability guidelines Pa
34、rt 1: Architecture and protocols. DVB-IP ETSI TS 102 034 (2007), Digital Video Broadcasting (DVB); Transport of MPEG-2 TS Based DVB Services over IP Based Networks. HGI Home Gateway Initiative (2006), Home Gateway Technical Requirements: Release 1.0. UPnP UPnP QoS (2006), UPnP QoS Architecture: 2. 2
35、 H series Supplement 11 (02/2009) 3 Definitions This supplement uses the following term defined elsewhere: 3.1 home network ITU-T H.622: Home network is the collection of elements that process, manage, transport, and store information, thus enabling the connection and integration of multiple computi
36、ng, control, monitoring, communication, and entertainment devices in the home. 4 Abbreviations and acronyms This supplement uses the following abbreviations and acronyms: ATM Asynchronous Transfer Mode BE Best Effort DLNA Digital Living Network Alliance DSCP DiffServ Code Point HGI Home Gateway Init
37、iative HPNA Home Phoneline Networking Alliance HTTP HyperText Transfer Protocol IP Internet Protocol PLC Power Line Communication QoS Quality of Service SDO Standards Development Organization TIN Traffic Importance Number VAS Value Added Service VLAN Virtual Local Area Network WMM Wi-Fi Multimedia 5
38、 Framework for home network QoS Access GW Access NW Primary Terminal Primary Domain Secondary Domain Secondary Terminal Figure 5-1 Application model of home network defined in ITU-T H.622 As defined in ITU-T H.622, it is recognized that the home network has two distinctive roles: connecting terminal
39、 devices to the access network and connecting terminal devices for communications within the home. The two different cases are referred to as primary and secondary domains, respectively. The primary domain is a collection of home network elements functioning as H series Supplement 11 (02/2009) 3 an
40、extension of the access network and thus connecting the primary terminal, which terminates multimedia services offered by the network and service provider. In the same way, the secondary domain is a collection of home network elements connecting primary and/or secondary terminals for communications
41、within the home. Figure 5-2 illustrates the framework for harmonization of class-based QoS solutions that need to be studied in this context. Figure 5-2 Framework for harmonization of home network QoS solutions The four interfaces on which harmonization should be established are defined in Figure 5-
42、2. Interface (A) Interface (A) provides the association between an IP-level priority and an application (or a protocol used in the application). It is important to assign a protocol to a certain level of priority. Each application is not aware of what types of data link technology are used in the ho
43、me network. Also, the data link technology used between bridging devices, not directly connected to the end device, is hardly visible to the end device and the application residing in the end device. A typical use of this interface is to give a higher priority for audio and video stream than other t
44、ypes of data traffic such as HTTP for web services. Interface (B) Interface (B) provides the association between an IP-level priority and a data-link level priority. This interface is important because it is not likely that all the bridging devices in the home network are able to read the IP-level p
45、riority, DSCP value. Instead of reading DSCP value, these devices typically read a lower layer marking value such as Ethernet priority. Without having any consistent policy of this interface, desirable QoS in the home network is not expected. Interface (C) Interface (C) provides the association betw
46、een an application and a data-link level priority. Unlike interfaces (A) and (B), the direct use of this interface is a minor case. However, some data link ApplicationProtocolEthernetWireless LAN HPNAPLC CoaxData linkIP Access Network Home Network(A)(D)IP(B)(C) Secondary Domain Primary Domain 4 H se
47、ries Supplement 11 (02/2009) specifications, for example, IEEE 802.1D, contain the indication of a certain priority associated with an application. It may be useful to make consistency at this interface to realize a solid and well-harmonized QoS scheme. Interface (D) Interface (D) provides the assoc
48、iation of an IP-level priority between the access and the home network. If the policy, e.g., a choice of DSCP value, of the network provider is different from that of the home network, remarking of packets needs to take place at the device around UNI. Currently, a few documents address this interfac
49、e. However, it is essential for end-to-end QoS, and therefore further study is needed. 6 Comparison and issues 6.1 Comparison of existing practices There are documents published by various SDOs defining priority levels and the use of marking. Analysis of these documents gives a good guidance on how to harmonize home network QoS solutions. Table 6-1 lists the documents indicating the use of traffic priority levels in the home network. Table 6-1 List of analysed documents Document Note DSL-F T
