1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T Y.1414TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2004) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT GENERATION NETWORKS Internet protocol aspects Interworking Voice services MPLS network interworking ITU-T Recom
2、mendation Y.1414 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.400Y.4
3、99 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 Y.1
4、200Y.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.2099
5、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 arc
6、hitectures 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.1414 (07/2004) i ITU-T Recommendation Y.1414 Voice services MPLS network interworking Summary This Recommendation focuses
7、 on the required functions and procedures necessary for support of narrow-band voice services by MPLS networks. Details of the encapsulation of encoded audio streams in MPLS packets are specified. Source ITU-T Recommendation Y.1414 was approved on 29 July 2004 by ITU-T Study Group 13 (2001-2004) und
8、er the ITU-T Recommendation A.8 procedure. Keywords AAL type 2, Interworking, MPLS, Network, VoIP, Voice services, User Plane. ii ITU-T Rec. Y.1414 (07/2004) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU
9、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 on a worldwide basis. The World Telecommunication Standardizat
10、ion 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 techno
11、logy 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 administration and a recognized operating agency. Complianc
12、e 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 mandatory provisions are met. The words “shall“ or some other obligato
13、ry 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 attention to the possibility that the practice or implementation o
14、f 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 outside of the Recommendation development process. As of the
15、 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, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to con
16、sult the TSB patent database. ITU 2004 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. Y.1414 (07/2004) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 3 4 Abbreviations 3 5 Conventions 4 6
17、 Voice services MPLS network interworking. 4 7 General requirements 5 7.1 User plane requirements. 6 7.2 Control plane aspects 6 7.3 Management plane aspects. 6 7.4 Traffic management aspects. 7 8 Functional group considerations for voice services MPLS network interworking . 7 8.1 MPLS transport lab
18、el 7 8.2 Interworking label 7 8.3 Common interworking indicators. 7 9 Voice over IP over MPLS. 9 10 Voice over MPLS using AAL type 2 SSCS for narrowband services . 9 10.1 Transport label 10 10.2 Interworking label 10 10.3 Common interworking indicators. 10 10.4 Payload . 10 11 Voice over MPLS using
19、MPLS Forum IA 1.0 . 10 11.1 Transport label 10 11.2 Interworking label 10 11.3 Common interworking indicators. 10 11.4 Payload . 11 Appendix I Primary and control sub-frames used in MPLS Forum 1.0 . 11 I.1 Sub-frames 11 I.2 Primary Sub-frame . 12 I.3 Control sub-frame. 12 I.4 Format of the primary s
20、ub-frame . 13 iv ITU-T Rec. Y.1414 (07/2004) Introduction This Recommendation focuses on the required functions and procedures necessary for support of narrow-band voice services by MPLS networks. Details of the encapsulation of encoded audio streams in MPLS packets are specified. ITU-T Rec. Y.1414
21、(07/2004) 1 ITU-T Recommendation Y.1414 Voice services MPLS network interworking 1 Scope This Recommendation focuses on the required functions and procedures necessary for support of narrow-band voice services by MPLS networks. ITU-T Rec. Y.1261 1 describes the service requirements and architecture
22、for transport of voice services over MPLS networks. Narrow-band voice services include encoded audio streams, telephony call progress tones, fax, and optionally circuit mode data. This Recommendation specifies encapsulation of encoded audio in MPLS packets. Algorithms for encoding audio streams are
23、beyond the scope of this Recommendation. This Recommendation includes three modes: voice over IP over MPLS; voice over MPLS using AAL type 2 SSCS 2 and 3 for narrow-band services; and voice over MPLS using MPLS Forum IA 1.0 4. 2 References The following ITU-T Recommendations and other references con
24、tain 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 t
25、he 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 reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a
26、 Recommendation. 1 ITU-T Recommendation Y.1261 (2002), Service requirements and architecture for voice services over Multi-Protocol Label Switching. 2 ITU-T Recommendation I.366.2 (2000), AAL type 2 service specific convergence sublayer for narrow-band services, plus Corrigendum 1 (2002). 3 ITU-T Re
27、commendation I.363.2 (2000), B-ISDN ATM Adaptation Layer specification: Type 2 AAL. 4 MPLS Forum Implementation Agreement MPLS Forum 1.0 (2001), Voice Over MPLS Bearer Transport. 5 ITU-T Recommendation Y.1411 (2003), ATM-MPLS network interworking Cell mode user plane interworking. 6 ITU-T Recommenda
28、tion G.805 (2000), Generic functional architecture of transport networks. 7 ITU-T Recommendation G.711 (1988), Pulse code modulation (PCM) of voice frequencies. 8 ITU-T Recommendation G.723.1 (1996), Speech coders: Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit
29、/s. 9 ITU-T Recommendation G.726 (1990), 40, 32, 24, 16 kbit/s Adaptive Differential Pulse Code Modulation (ADPCM). 10 ITU-T Recommendation G.727 (1990), 5-, 4-, 3- and 2-bit/sample embedded adaptive differential pulse code modulation (ADPCM). 2 ITU-T Rec. Y.1414 (07/2004) 11 ITU-T Recommendation G.
30、729 (1996), Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear-prediction (CS-ACELP). 12 ETSI EN 301 703 V7.0.2 (1999), Digital Cellular Telecommunications System (Phase 2+) (GSM) Adaptive Multi-Rate (AMR); Speech processing functions; General description (GSM 06.71
31、 version 7.0.2 Release 1998). 13 ITU-T Recommendation G.722 (1988), 7 kHz audio-coding within 64 kbit/s. 14 ITU-T Recommendation G.722.1 (2000), Coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss. 15 ITU-T Recommendation G.722.2 (2003), Wideband coding of speech at ar
32、ound 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB). 16 ITU-T Recommendation G.711 Appendix I (1999), A high quality low-complexity algorithm for packet loss concealment with G.711. 17 ITU-T Recommendation Q.23 (1988), Technical features of push-button telephone sets. 18 ITU-T Recommendation
33、Q.24 (1988), Multifrequency push-button signal reception. 19 ITU-T Recommendation E.180/Q.35 (1998), Technical characteristics of tones for the telephone service. 20 ITU-T Recommendation I.251.3 (1992), Number identification supplementary services: Calling Line Identification Presentation. 21 ITU-T
34、Recommendation Q.310-Q.332 (1988), Specifications of Signalling System R1. 22 ITU-T Recommendation Q.400-Q.490 (1988), Specifications of Signalling System R2. 23 ITU-T Recommendation Q.724 (1988), Telephone user part signalling procedures, plus Amendment 1 (1993). 24 ITU-T Recommendation T.4 (2003),
35、 Standardization of Group 3 facsimile terminals for document transmission. 25 ITU-T Recommendation T.30 (2003), Procedures for document facsimile transmission in the general switched telephone network. 26 ITU-T Recommendation V.17 (1991), A 2-wire modem for facsimile applications with rates up to 14
36、 400 bit/s. 27 ITU-T Recommendation V.29 (1988), 9600 bits per second modem standardized for use on point-to-point 4-wire leased telephone-type circuits. 28 ITU-T Recommendation V.18 (2000), Operational and interworking requirements for DCEs operating in the text telephone mode. 29 IETF RFC 3032 (20
37、01), MPLS Label Stack Encoding. 30 IETF RFC 3031 (2001), Multiprotocol Label Switching Architecture. 31 IETF RFC 768 (1980), User Datagram Protocol. 32 IETF RFC 3550 (2003), RTP: A Transport Protocol for Real-Time Applications. 33 ATM Forum specification af-vmoa-0145.001 (2003), Loop Emulation Servi
38、ce Using AAL2 Rev 1. 34 MPLS and Frame Relay Alliance 5.0.0 (2003), I.366.2 Voice Trunking Format over MPLS, Implementation Agreement. ITU-T Rec. Y.1414 (07/2004) 3 3 Definitions This Recommendation defines or uses the following terms: 3.1 interworking: See ITU-T Rec. Y.1411 5. 3.2 interworking func
39、tion (IWF): See ITU-T Rec. Y.1411 5. 3.3 ingress IWF: The point where the voice services are encapsulated into an MPLS packet (Voice-to-MPLS direction). 3.4 egress IWF: The point where the voice services are de-encapsulated from an MPLS packet (MPLS-to-voice direction). 4 Abbreviations This Recommen
40、dation uses the following abbreviations: AAL2 ATM Adaptation Layer 2 CAS Channel Associated Signalling CCS Common Channel Signalling CID Channel Identifier CLI Calling Line Identification CPS Common Part Sublayer CPT Call Progress Tone CRC Cyclic Redundancy Check CU Combined Use DTMF Dual Tone Multi
41、 Frequency HEC Header Error Control IP Internet Protocol IWF InterWorking Function LSP Label Switched Path LSR Label Switching Router MPLS Multi-Protocol Label Switching MTU Maximum Transport Unit OAM Operation And Maintenance PDU Protocol Data Unit QoS Quality of Service RFC Request for Comments RT
42、P Real Time Protocol SSCS Service Specific Convergence Sublayer (of AAL) STF Start Field TDM Time Division Multiplexing TTL Time To Live UDP User Datagram Protocol 4 ITU-T Rec. Y.1414 (07/2004) UUI User-to-User Indication VoIP Voice over IP VS Voice Services 5 Conventions In this Recommendation the
43、term voice services is synonymous with narrow-band services, and includes 8 kHz digitized audio (carrying voice, telephony tones, fax and modem transmissions, etc). It optionally may include 16 kHz digitized audio (“wideband speech“), and 64 kbit/s data. In this Recommendation voice services are con
44、sidered without regard to the physical interface over which they are provided. In particular, while this physical interface may be a TDM link carrying multiple voice-grade channels, other cases are frequently encountered. 6 Voice services MPLS network interworking Figure 6-1 provides a general netwo
45、rk architecture for support of narrow-band voice services by MPLS networks. For the voice services-to-MPLS direction, the continuous voice services data (stream or frame) is encapsulated into an MPLS packet by the interworking function (IWF). For the MPLS-to-voice services direction, the voice servi
46、ces data is extracted from the MPLS packets. The MPLS network contains a number of Label Switching Routers (LSR), and Label Switched Paths (LSP). An example LSP is shown as a solid line in Figure 6-1. Figure 6-2 depicts the network functional architecture of voice services-MPLS network interworking
47、using the diagrammatic techniques of ITU-T Rec. G.805 6. Figure 6-3 shows the network reference model and protocol layers for user plane aspects of voice services-MPLS interworking. Figure 6-1/Y.1414 Reference architecture for voice services-MPLS network interworking ITU-T Rec. Y.1414 (07/2004) 5 Fi
48、gure 6-2/Y.1414 Functional architecture of voice services-MPLS network interworking depicted according to the diagrammatic conventions of G.805 Figure 6-3/Y.1414 Network reference model and protocol layers for voice services-MPLS user plane interworking This Recommendation specifies voice services-M
49、PLS network interworking for three of the possible solutions identified in Appendix II/Y.1261 1. The three solutions specified in this Recommendation are: voice over IP over MPLS; voice over MPLS using AAL type 2 SSCS for narrow-band services; and voice over MPLS using MPLS Forum IA 1.0. 7 General requirements A set of service requirements for Voice Services over MPLS have been identified in ITU-T Rec. Y.1261 1. This clause identifies specific requirement
