1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T J.1103 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (08/2015) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Switched digital video over cable networks Transmission
2、specification for IP-based switched digital video using data over cable service interface specifications Recommendation ITU-T J.1103 Rec. ITU-T J.1103 (08/2015) i Recommendation ITU-T J.1103 Transmission specification for IP-based switched digital video using data over cable service interface specif
3、ications Summary Recommendation ITU-T J.1103 describes the transmission specifications of IP-based switched digital video (SDV) using data over cable service interface specifications (DOCSIS) in a digital cable network. The cable broadcasting system has been changed to use resources efficiently and
4、to transmit said resources in such a way that the varying needs of subscribers are easily accommodated. The transmission specifications described in this Recommendation are defined according to Recommendation ITU-T J.1101, Functional requirements for IP-based switched digital video using data over c
5、able service interface specifications. These specifications are designed to maintain quality of service (QoS) while using bandwidth effectively in a hybrid fibre/coaxial (HFC) network environment. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T J.1103 2015-08-13 9 11.1002/10
6、00/12572 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T J.1103 (08/2015) FOREWORD The International Telecommunication Unio
7、n (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 studying technical, operating and tariff questions an
8、d 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 groups which, in turn, produce Recommendations on the
9、se 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 ISO and IEC. NOTE In this Recommendation, the expr
10、ession “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 provisions (to ensure, e.g., interoperability or applicab
11、ility) 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 such words does not suggest that compliance with the
12、Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU 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 position concerning the evidence, validity or applicabilit
13、y 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, protected by patents, which may be required to implement th
14、is 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 2015 All rights reserved. No part of this publication may be reproduced, by any means wha
15、tsoever, without the prior written permission of ITU. Rec. ITU-T J.1103 (08/2015) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 1 4 Abbreviations and acronyms 2 5 Conventions 3 6 IP-based SDV reference
16、 model 3 6.1 Transmission function 4 6.2 Subscriber function . 4 7 Transmission specification . 5 7.1 Service flow processing 5 7.2 Packet scheduling . 6 7.3 MAC header processing . 7 7.4 MPEG-2 TS convergence . 12 Annex A The service flow classification process . 15 Annex B Examples of MPEG-2 TS en
17、capsulation . 19 Bibliography. 21 Rec. ITU-T J.1103 (08/2015) 1 Recommendation ITU-T J.1103 Transmission specification for IP-based switched digital video using data over cable service interface specifications 1 Scope This Recommendation defines the transmission specifications of the IP-based switch
18、ed digital video (SDV) using data over cable service interface specification (DOCSIS). The transmission specifications described in this Recommendation are defined according to ITU-T J.1101. The transmission specifications described in this Recommendation are defined as follows: multicast service fl
19、ow processing transmission specifications multicast packet scheduling transmission specifications media access control (MAC) header processing transmission specifications MPEG-2 TS convergence transmission specifications. 2 References The following ITU-T Recommendations and other references contain
20、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; users of this Recommendation are therefore encouraged to investigate the po
21、ssibility 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 reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Reco
22、mmendation. ITU-T J.210 Recommendation ITU-T J.210 (2006), Downstream RF interface for cable modem termination systems. ITU-T J.222.1 Recommendation ITU-T J.222.1 (2007), Third-generation transmission systems for interactive cable television services IP cable modems: Physical layer specification. IT
23、U-T J.222.2 Recommendation ITU-T J.222.2 (2007), Third-generation transmission systems for interactive cable television services IP cable modems: MAC and Upper Layer protocols. ITU-T J.1101 Recommendation ITU-T J.1101 (2012), Functional requirements for IP-based switched digital video using data ove
24、r cable service interface specifications. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following term defined elsewhere: 3.1.1 IP-based SDV ITU-T J.1101: A service mechanism which provides interfaces and functionalities to enable cable television system operators to offer Q
25、oS-guaranteed broadcasting and multicasting. 3.2 Terms defined in this Recommendation None. 2 Rec. ITU-T J.1103 (08/2015) 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: CCP Channel Charge Protocol CM Cable Modem CMTS Cable Modem Termination System CRC
26、 Cyclic Redundancy Check DA Destination Address DC Downstream Channel DCID Downstream Channel Identifier DEPI Downstream External PHY Interface DMPI DOCSIS MAC-PHY Interface DOCSIS Data Over Cable Service Interface Specifications DRFI Downstream Radio Frequency Interface DS Downstream DSID Downstrea
27、m Service Identifier EH Extended Header EHDR Extended MAC Header FC Frame Control FEC Forward Error Correction FTP File Transfer Protocol GBE Giga Bit Ethernet HCS Header Check Sequence HFC Hybrid Fibre/Coaxial IGMP Internet Group Management Protocol IP Internet Protocol IPC Inter Process Communicat
28、ions MAC Media Access Control M-CMTS Modular Cable Modem Termination System MDD MAC Domain Descriptor MIB Management Information Base MPEG Moving Picture Experts Group MSB Most Significant Bit NSI Network Service Interface PDU Protocol Data Unit PHY Physical Layer PID Packet Identifier PUSI Payload
29、Unit Start Indicator Rec. ITU-T J.1103 (08/2015) 3 QAM Quadrature Amplitude Modulation QoS Quality of Service RPC Remote Procedure Call SA Source Address SDV Switched Digital Video SF Service Flow SFID Service Flow Identifier SID Service Identifier SIP Session Initiation Protocol STB Set-Top Box VSI
30、 Video Service Interface 5 Conventions In this Recommendation: The keywords “is required to“ indicate a requirement which must be strictly followed and from which no deviation is permitted if conformance to this document is to be claimed. The keywords “is recommended“ indicate a requirement which is
31、 recommended but which is not absolutely required. Thus this requirement need not be present to claim conformance. The keywords “is prohibited from“ indicate a requirement which must be strictly followed and from which no deviation is permitted if conformance to this document is to be claimed. The k
32、eywords “can optionally“ indicate an optional requirement which is permissible, without implying any sense of being recommended. This term is not intended to imply that the vendors implementation must provide the option and the feature can be optionally enabled by the network operator/service provid
33、er. Rather, it means the vendor may optionally provide the feature and still claim conformance with the specification. In the body of this Recommendation and its annexes, the words shall, shall not, should, and may sometimes appear, in which case they are to be interpreted, respectively, as is requi
34、red to, is prohibited from, is recommended, and can optionally. The appearance of such phrases or keywords in an appendix or in material explicitly marked as informative are to be interpreted as having no normative intent. 6 IP-based SDV reference model As shown in Figure 1, functionally IP-based SD
35、V using the DOCSIS system can be categorized into three parts: the transmission function the subscriber function the control function. 4 Rec. ITU-T J.1103 (08/2015) Figure 1 Diagram of an IP-based switched digital video system 6.1 Transmission function The transmission function processes the DOCSIS
36、frame header and transmits it to the multicast service group. The transmission function consists of an SDV transmission function and a downstream PHY function. The SDV transmission function processes service flow and packet header processing on the DOCSIS MAC layer ITU-T J.222.2. The downstream PHY
37、function transmits the DOCSIS header processed video stream to the subscriber. 6.1.1 SDV transmission function The SDV transmission function processes service flow and does packet header processing on the DOCSIS MAC layer. 6.1.2 Downstream PHY function The downstream PHY ITU-T J.222.1 function trans
38、mits the DOCSIS header processed video stream to the subscriber. 6.2 Subscriber function The subscriber function processes the video data stream from the transmission function. The subscriber function consists of the SDV client service function and SDV receiver function. The subscriber function also
39、 sends request information of an SDV video service programme to the control function. 6.2.1 SDV client function The SDV client function recovers an IP-based received video data stream from an MPEG-2 based video stream and outputs it to the set-top box (STB). 6.2.2 SDV receiver function The SDV recei
40、ver function processes physical signal processing; it is a function of the DOCSIS cable modem. Rec. ITU-T J.1103 (08/2015) 5 7 Transmission specification Figure 2 shows the structure of an IP-based SDV transmission module. The IP-based SDV transmission module is required to consist of service flow p
41、rocessing, packet scheduling, MAC header processing and MPEG-2 TS convergence. Service flow processing is required to obtain the following information on input packets: the packet type, the service flow ID, the downstream service ID, the transmission priority and the available downstream transmissio
42、n channel list. Packet scheduling is required to schedule the service flow by deciding on the available downstream channel, multiplexing the DOCSIS management message and multicasting the video data packet. MAC header processing is required to process the packet according to the transmission priorit
43、y and to create the DOCSIS MAC header according to the service flow information of the input packet. MPEG-2 TS convergence is required to place the DOCSIS MAC frame in the queue and to map the DOCSIS MAC frame to MPEG-2 TS. Figure 2 The architecture of IP-based SDV transmission 7.1 Service flow proc
44、essing The service flow processing block is required to obtain the following information from the input packet: packet type, downstream service identifier (DSID), service flow identifier (SFID) priority downstream channel (DC) list bitmask The packet scheduling block is required to determine the ava
45、ilable channel using this information. The packet format of a transmission specification is shown in Figure 3. Detailed definitions of the header elements are provided in Table 1. The TYPE part consists of five elements as follows: TYPE_CAST, TYPE_BOND, TYPE_PRIORITY, TYPE_MESSAGE and TYPE_RSVD. 6 R
46、ec. ITU-T J.1103 (08/2015) Figure 3 The data packet format Table 1 Data packet frame header Field Length (bits) Function TYPE_CAST 2 TYPE: 00 Unicast 01 Multicast 10 Broadcast 11 Reserved TYPE_BOND 1 TYPE BONDING CONDITION 0 Channel non-bonded 1 Channel bonded TYPE_PRIORITY 1 TYPE ZERO PRIORITY 0 Ze
47、ro priority 1 Non-zero priority TYPE_MESSAGE 1 TYPE MESSAGE 0 User packet 1 MAC management message TYPE_RSVD 3 TYPE Reserved PRIORITY 4 PRIORITY 0x 0 7: High value is high priority DSID 20 Downstream ID DC LIST MASK 32 Service available channel list SFID_ADDR 32 Service flow ID The service flow clas
48、sification process is shown in Figure A.1. 7.2 Packet scheduling Packet scheduling is required to determine the available downstream channel. It is possible to transmit a management message for a determined channel. The management packet format of a transmission specification is shown in Figure 4. D
49、etailed definitions of the header elements are provided in Table 2. Rec. ITU-T J.1103 (08/2015) 7 Figure 4 The management packet format Table 2 Management packet frame header Field Length (Bit) Function DCID 8 Down channel ID UCID 8 Up channel ID LEN 16 Length 7.3 MAC header processing The MAC header processing unit is required to classify the packet and store it in the queue according to the transmission priority. The MAC header processing unit is required to process the stored pa
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