1、 International Telecommunication Union ITU-T Y.1453TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2006) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Internet protocol aspects Interworking TDM-IP interworking User plane interworking ITU-T Re
2、commendation Y.1453 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.199 Services, applications and middleware Y.200Y.299 Network aspects Y.300Y.399 Interfaces and protocols Y.400
3、Y.499 Numbering, addressing and naming Y.500Y.599 Operation, administration and maintenance Y.600Y.699 Security Y.700Y.799 Performances Y.800Y.899 INTERNET PROTOCOL ASPECTS General Y.1000Y.1099 Services and applications Y.1100Y.1199 Architecture, access, network capabilities and resource management
4、Y.1200Y.1299 Transport Y.1300Y.1399 Interworking Y.1400Y.1499 Quality of service and network performance Y.1500Y.1599 Signalling Y.1600Y.1699 Operation, administration and maintenance Y.1700Y.1799 Charging Y.1800Y.1899 NEXT GENERATION NETWORKS Frameworks and functional architecture models Y.2000Y.20
5、99 Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Service aspects: Interoperability of services and networks in NGN Y.2250Y.2299 Numbering, naming and addressing Y.2300Y.2399 Network management Y.2400Y.2499 Network control
6、architectures and protocols Y.2500Y.2599 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. Y.1453 (03/2006) i ITU-T Recommendation Y.1453 TDM-IP interworking User plane interworking Summary This Recommendation a
7、ddresses required functions for network interworking between TDM networks up to DS3 or E3 rates and IP networks, in order to transport TDM traffic over IP networks. This Recommendation addresses user plane interworking mechanisms, connection multiplexing and procedures. These interworking mechanisms
8、 must ensure that TDM timing, signalling, voice quality, and alarm integrity be maintained. Details of the interworking model and required interworking functions are described. This Recommendation may not be suitable for use by Recognized Operating Agencies due to possible degradation of network syn
9、chronization performance as compared with native TDM transport. Source ITU-T Recommendation Y.1453 was approved on 29 March 2006 by ITU-T Study Group 13 (2005-2008) under the ITU-T Recommendation A.8 procedure. Keywords Interworking, IP, network interworking, TDM, UDP, user plane. ii ITU-T Rec. Y.14
10、53 (03/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff q
11、uestions 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 groups which, in turn, produce Recommendat
12、ions 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 ISO and IEC. NOTE In this Recommendatio
13、n, 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 provisions (to ensure e.g. interoperability or
14、 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 such words does not suggest that compliance
15、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 position concerning the evidence, validity or ap
16、plicability 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 im
17、plement 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. ITU 2006 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the p
18、rior written permission of ITU. ITU-T Rec. Y.1453 (03/2006) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 3 4 Abbreviations and acronyms 3 5 Conventions 4 6 TDM-IP interworking. 5 7 General requirements 6 7.1 User plane requirements. 6 7.2 Management plane aspects. 7 7.3 Fault management
19、 aspects 8 7.4 Traffic management aspects. 9 7.5 Connection admission control for the IWF 9 8 Functional group considerations for TDM-IP network interworking. 10 8.1 IP. 10 8.2 UDP 10 8.3 Common interworking indicators. 10 8.4 Optional timing information. 12 8.5 TDM payload 12 8.6 Summary of encapsu
20、lation format 12 9 Payload formats 16 9.1 Structure-agnostic transport 16 9.2 Structure-aware transport . 17 10 Timing aspects 20 11 Packet loss aspects 20 12 Support of CAS and CCS . 20 12.1 Support of CAS 20 12.2 Support of CCS. 20 13 Security considerations. 21 Appendix I Optional processing of H
21、DLC-based CCS signals 21 Appendix II IP network performance metrics. 21 II.1 Errors in the IP network that impact TDM service 21 II.2 Relationship to TDM service impairment metrics . 22 II.3 Availability requirements . 23 II.4 Voice quality requirements. 23 Appendix III Suggested payload sizes for s
22、tructure-agnostic transport . 24 Appendix IV Suggested number of AAL1 SAR PDUs per packet. 24 iv ITU-T Rec. Y.1453 (03/2006) Introduction There is a need to define network interworking wherein traffic from conventional synchronous or plesiochronous networks (hereafter denoted TDM networks) is transp
23、orted over IP networks. Such interworking must ensure that TDM timing, signalling, voice quality, and alarm integrity be maintained. ITU-T Rec. Y.1453 (03/2006) 1 ITU-T Recommendation Y.1453 TDM-IP interworking User plane interworking 1 Scope This Recommendation addresses required functions for netw
24、ork interworking between TDM networks up to and including DS3/E3 rates and IP networks, in order to transport TDM traffic over IP networks. Transport of higher rate TDM services (such as SDH) over IP networks is beyond the scope of this Recommendation. This Recommendation addresses user plane interw
25、orking mechanisms, connection multiplexing and related procedures. These interworking mechanisms must ensure that TDM timing, signalling, telephony voice quality, and alarm integrity be maintained. Details of the interworking model and required interworking functions are described. This Recommendati
26、on may not be suitable for use by recognized operating agencies (ROAs) 1 due to possible degradation of network synchronization performance as compared with native TDM transport. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this
27、 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 possibility of applying the most recent editi
28、on 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 Recommendation. 1 ITU-T Recommendation F.110 (1
29、996), Operational provisions for the maritime mobile service. 2 ITU-T Recommendation Y.1411 (2003), ATM-MPLS network interworking Cell mode user plane interworking. 3 ITU-T Recommendation Y.1413 (2004), TDM-MPLS network interworking User plane interworking. 4 ITU-T Recommendation G.809 (2003), Funct
30、ional architecture of connectionless layer networks. 5 ITU-T Recommendation G.702 (1988), Digital hierarchy bit rates. 6 ITU-T Recommendation G.705 (2000), Characteristics of plesiochronous digital hierarchy (PDH) equipment functional blocks. 7 ITU-T Recommendation G.114 (2003), One-way transmission
31、 time. 8 ITU-T Recommendation G.826 (2002), End-to-end error performance parameters and objectives for international, constant bit-rate digital paths and connections. 9 ITU-T Recommendation G.823 (2000), The control of jitter and wander within digital networks which are based on the 2048 kbit/s hier
32、archy. 10 ITU-T Recommendation G.824 (2000), The control of jitter and wander within digital networks which are based on the 1544 kbit/s hierarchy. 11 IETF RFC 791 (1981), Internet Protocol DARPA Internet Program Protocol Specification. 12 IETF RFC 2460 (1998), Internet Protocol, Version 6 (IPv6) Sp
33、ecification. 2 ITU-T Rec. Y.1453 (03/2006) 13 IETF RFC 768 (1980), User Datagram Protocol. 14 ITU-T Recommendation G.703 (2001), Physical/electrical characteristics of hierarchical digital interfaces. 15 ITU-T Recommendation V.36 (1988), Modems for synchronous data transmission using 60-180 kHz grou
34、p band circuits. 16 ITU-T Recommendation V.37 (1988), Synchronous data transmission at a data signalling rate higher than 72 kbit/s using 60-108 kHz group band circuits. 17 ITU-T Recommendation I.231.1 (1988), Circuit-mode bearer service categories Circuit-mode 64 kbit/s unrestricted, 8 kHz structur
35、ed bearer service. 18 ANSI T1.107 (2002), Digital Hierarchy Formats Specifications. 19 ITU-T Recommendation G.751 (1988), Digital multiplex equipments operating at the third order bit rate of 34 368 kbit/s and the fourth order bit rate of 139 264 kbit/s and using positive justification. 20 ITU-T Rec
36、ommendation G.704 (1998), Synchronous frame structures used at 1544, 6312, 2048, 8448 and 44 736 kbit/s hierarchical levels. 21 ITU-T Recommendation Q.700 (1993), Introduction to CCITT Signalling System No. 7. 22 ITU-T Recommendation Q.931 (1998), ISDN user-network interface layer 3 specification fo
37、r basic call control. 23 ITU-T Recommendation I.363.1 (1996), B-ISDN ATM Adaptation Layer specification: Type 1 AAL. 24 IETF RFC 3550 (2003), RTP: A Transport Protocol for Real-Time Applications. 25 ITU-T Recommendation Y.1540 (2002), Internet protocol data communication service IP packet transfer a
38、nd availability performance parameters. 26 IETF RFC 2474 (1998), Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers. 27 IETF RFC 3246 (2002), An Expedited Forwarding PHB (Per-Hop Behavior). 28 IETF RFC 2210 (1997), The Use of RSVP with IETF Integrated Services. 2
39、9 IETF RFC 2212 (1997), Specification of Guaranteed Quality of Service. 30 ATM Forum af-vtoa-0078.000 (1997), Circuit Emulation Service 2.0. 31 ITU-T Recommendation G.802 (1988), Interworking between networks based on different digital hierarchies and speech encoding laws. 32 ITU-T Recommendation Q.
40、921 (1997), ISDN user network interface Data link layer specification. 33 ITU-T Recommendation G.827 (2003), Availability performance parameters and objectives for end-to-end international constant bit-rate digital paths. 34 ITU-T Recommendation G.1020 (2003), Performance parameter definitions for q
41、uality of speech and other voiceband applications utilizing IP networks. 35 ITU-T Recommendation P.800 (1996), Methods for subjective determination of transmission quality. 36 ITU-T Recommendation P.862 (2001), Perceptual evaluation of speech quality (PESQ): An objective method for end-to-end speech
42、 quality assessment of narrow-band telephone networks and speech codecs. ITU-T Rec. Y.1453 (03/2006) 3 37 ITU-T Recommendation I.231.5 (1988), Circuit-mode bearer service categories: Circuit-mode 2 64 kbit/s unrestricted, 8 kHz structured bearer service. 38 ITU-T Recommendation I.231.10 (1992), Circ
43、uit-mode bearer service categories: Circuit-mode multiple-rate unrestricted 8 kHz structured bearer service. 39 ITU-T Recommendation I.231.6 (1996), Circuit-mode bearer service categories: Circuit-mode 384 kbit/s unrestricted, 8 kHz structured bearer service. 3 Definitions This Recommendation uses o
44、r defines the following terms: 3.1 interworking: See ITU-T Rec. Y.1411 2. 3.2 interworking flow: A pair of G.809 flows 4 capable of simultaneously transferring information in opposite directions over an IP network for the purpose of transporting TDM traffic. 3.3 interworking function (IWF): See ITU-
45、T Rec. Y.1411. 3.4 ingress IWF: The point where the continuous TDM stream is segmented and encapsulated into IP packets (TDM-to-IP direction). 3.5 egress IWF: The point where TDM segments are de-encapsulated from IP packets and reassembled into a continuous TDM stream (IP-to-TDM direction). 4 Abbrev
46、iations and acronyms This Recommendation uses the following abbreviations and acronyms: AAL ATM Adaptation Layer AIS Alarm Indication Signal AP Access Point ATM Asynchronous Transfer Mode CAS Channel Associated Signalling CCS Common Channel Signalling CES Circuit Emulation Service CP Connection Poin
47、t CSI Convergence Sublayer Indication CSRC Contributing Source dAIS AIS defect Diffserv Differentiated Services dLOA Loss of Alignment defect dLOS Loss of Signal defect DSn Digital Signal level n EF PHB Expedited Forwarding Per Hop Behaviour En Electrical Interface Signal, level n FAS Frame Alignmen
48、t Signal FCS Frame Check Sequence 4 ITU-T Rec. Y.1453 (03/2006) GS Guaranteed Service HDLC High level Data Link Control Intserv Integrated Services IP Internet Protocol ISDN Integrated Services Digital Network IWF InterWorking Function LOF Loss of Frame Synchronization LOS Loss of Signal MPLS Multi-
49、Protocol Label Switch MTU Maximum Transport Unit OAM Operation, Administration and Maintenance PDU Protocol Data Unit PDV Packet Delay Variation PLC Packet Loss Concealment PM Performance Monitoring PRI Primary Rate Interface PSTN Public Switched Telephone Network PT Payload Type QoS Quality of Service ROA Recognized Operating Agency RDI Remote Defect Indication RFC Request for Comments RTP Real Time Protocol SAR Segmentation And Reassembly SRTS Sy
