1、 International Telecommunication Union ITU-T H.248.54TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (08/2007) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Gateway control protocol: MPLS support package ITU-T Recommendation H.248.54 ITU-
2、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.259 Codin
3、g 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 Sup
4、plementary 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 H.52
5、0H.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.559Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAND AND TRIPLE-PLAY MULTIMEDIA
6、SERVICES Broadband multimedia services over VDSL H.610H.619 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. H.248.54 (08/2007) i ITU-T Recommendation H.248.54 Gateway control protocol: MPLS support package Summary An H.248 media gateway may be connected to multipro
7、tocol label switching (MPLS) domains in various ways. ITU-T Recommendation H.248.54 defines an H.248 package that allows H.248 streams or terminations to bind to MPLS label switched paths. Source ITU-T Recommendation H.248.54 was approved on 29 August 2007 by ITU-T Study Group 16 (2005-2008) under t
8、he ITU-T Recommendation A.8 procedure. ii ITU-T Rec. H.248.54 (08/2007) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization S
9、ector (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 Standardization Assembly (WTSA), which meets ev
10、ery 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 technology which fall within ITU-Ts purvi
11、ew, 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. Compliance with this Recommendation is volun
12、tary. 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 obligatory language such as “must“ and the
13、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 of this Recommendation may involve t
14、he 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 date of approval of this Recommend
15、ation, 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 latest information and are therefore strongly urged to consult the TSB patent database at htt
16、p:/www.itu.int/ITU-T/ipr/. ITU 2008 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. H.248.54 (08/2007) iii CONTENTS Page 1 Scope 1 1.1 General MPLS networks 2 1.2 PSTN/ISDN evolution to NGN 2 1.3 ITU
17、-T NGN Release 1 2 1.4 Relation to “RACF for MPLS based (core) networks“ 2 2 References. 2 3 Definitions 3 3.1 Terms defined elsewhere 3 3.2 Terms defined in this Recommendation. 3 4 Abbreviations and acronyms 3 5 Conventions 3 6 MPLS package 4 6.1 Properties 4 6.2 Events . 4 6.3 Signals 4 6.4 Stati
18、stics 4 6.5 Error codes 4 6.6 Procedures 4 Appendix I Some examples for MPLS network architectures 5 I.1 Introduction 5 I.2 H.248 MG as a MPLS edge node. 5 I.3 LSPs as aggregates for MG-to-MG traffic . 6 Bibliography. 7 ITU-T Rec. H.248.54 (08/2007) 1 ITU-T Recommendation H.248.54 Gateway control pr
19、otocol: MPLS support package 1 Scope An H.248 media gateway (MG) may be connected to multiprotocol label switching (MPLS) domains in various ways. The connection is typically realized via H.248 IP terminations, but there could also be other types of H.248 ephemeral terminations due to the nature of
20、the MPLS protocol architecture. A basic MPLS building block is the so-called “Label Switched Path“ (LSP), see IETF RFC 3031. The LSP binds MPLS domains and H.248 MGs because LSPs are associated with H.248 ephemeral terminations. This is the basic application of the H.248 mpls package. The concept of
21、 LSP is very extensive, leading to a variety of scenarios involving LSP usage. Some examples are, most notably: LSP establishment and release: signalled LSP establishment and release via a label distribution protocol (LDP); provisioned LSP. NOTE 1 The mpls package is applicable for provisioned LSPs.
22、 The support of signalled LSPs is for further study. Hierarchical LSPs: relates to the MPLS label stack (see property stack; label stacking introduces hierarchy). NOTE 2 The mpls package supports “any“ legal MPLS label stack size. LSPs used for traffic engineering: basic LSPs (according to IETF RFC
23、3031) are not “traffic engineered“, e.g., transport characteristics are not explicitly assigned, however: LSPs may be used for “traffic engineering“ support (see IETF RFC 2702). NOTE 3 The dimension of traffic engineering is not addressed by the mpls package version 1 as such, but the package permit
24、s traffic engineered LSPs. Traffic engineered LSPs are under the responsibility of MG provisioning. The support of signalled, traffic engineered LSPs is for further study and requires the handling of the LSP control protocol (e.g., CR-LDP, RSVP-TE; see IETF RFC 2702 and IETF RFC 3468) by the MGC and
25、/or MG. LSP mapping on H.248 streams and terminations: The following relations are applicable for LSP, H.248 stream and termination mapping: 1:1:1 relation between a H.248 stream of an ephemeral termination and LSP; N:1:1 relation between H.248 streams, ephemeral termination and LSP; N:M:1 relation
26、between H.248 streams, ephemeral terminations and LSP. NOTE 4 The mpls package supports the above mapping schemes. LSP termination: an H.248 MG could terminate an LSP, in which case the MG acts as an MPLS edge node (more details are outlined in Appendix I); an H.248 MG could also provide a LSP traff
27、ic forwarding function. The LSP would then involve a single H.248 context with two ephemeral terminations. NOTE 5 The first case is supported. The second case does not require the capabilities of the mpls package. 2 ITU-T Rec. H.248.54 (08/2007) The mpls package may be used in various network enviro
28、nments. Several environments are described below. The function of the mpls package is further illustrated by examples in Appendix I. 1.1 General MPLS networks IETF RFC 3031 describes different MPLS node functions. Using this H.248 package, a H.248 MG could provide the MPLS edge node function. Furthe
29、r details are outlined in clause I.2. 1.2 PSTN/ISDN evolution to NGN ITU-T Y.2261 describes, amongst other things, core network evolution scenarios towards NGN. In these scenarios, the packet-switched network infrastructure could be MPLS-based. In this particular network evolution scenario, many H.2
30、48 MGs are interconnected in the transport domain. This is especially so for the call server-based evolution scenarios to NGN (see clause I.1.1 of ITU-T Y.2261, see also ITU-T Y.2271). Appendix I indicates how the mpls package could be used in such NGN use cases. 1.3 ITU-T NGN Release 1 MPLS is cons
31、idered as one of the transport technologies by NGN Release 1 (see clause 5.2 of ITU-T Y.2111). The policy enforcement physical entity (PE-PE) may control an entire MPLS domain, or theoretically may also be an element within an MPLS domain. The PE functional entity (PE-FE) may be physically realized
32、in an H.248 MG. In this case, the H.248 protocol may be profiled by the so-called “H.248 Rw profile“ (according to ITU-T Q.3303.2). The mpls package could then be used dependent on specific MPLS deployment scenarios (see above). 1.4 Relation to “RACF for MPLS based (core) networks“ For further descr
33、iption of MPLS in the NGN RACF, see the ITU-T Y-series of Recommendations. 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
34、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 edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recomme
35、ndations 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. ITU-T H.248.1 ITU-T Recommendation H.248.1 (2005), Gateway control protocol: Version 3. ITU-T Q.3303.2 ITU-T Recommendation Q.3303.2 (2
36、007), Resource control protocol No. 3 Protocol at the interface between a Policy Decision Physical Entity (PD-PE) and a Policy Enforcement Physical Entity (PE-PE) (Rw interface): H.248 alternative. ITU-T Y.2111 ITU-T Recommendation Y.2111 (2006), Resource and admission control functions in Next Gene
37、ration Networks. ITU-T Y.2261 ITU-T Recommendation Y.2261 (2006), PSTN/ISDN evolution to NGN. ITU-T Y.2271 ITU-T Recommendation Y.2271 (2006), Call server-based PSTN/ISDN emulation. IETF RFC 2702 IETF RFC 2702 (1999), Requirements for Traffic Engineering Over MPLS. ITU-T Rec. H.248.54 (08/2007) 3 IE
38、TF RFC 3031 IETF RFC 3031 (2001), Multiprotocol Label Switching Architecture. IETF RFC 3468 IETF RFC 3468 (2003), The Multiprotocol Label Switching (MPLS) Working Group decision on MPLS signaling protocols. 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation None
39、. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AMG Access MG CR-LDP Constraint-based Routing Label Distribution Protocol FEC Forwarding Equivalence Class LDP Label Distribution Protocol LER Label Edge Router LSP Label Switched Path LSR Label Switchi
40、ng Router MG Media Gateway MGC Media Gateway Controller MPLS MultiProtocol Label Switching NGN Next Generation Network PE-FE Policy Enforcement Functional Entity PE-PE Policy Enforcement Physical Entity RACF Resource Admission Control Function RSVP-TE Resource Reservation Protocol Traffic Engineerin
41、g TMG Trunking MG 5 Conventions None. 4 ITU-T Rec. H.248.54 (08/2007) 6 MPLS package Package Name: MPLS package PackageID: mpls (0x0090) value allocated by IANA. Description: This package enables a specific MPLS label stack to be passed to the MG to be applied to the given termination/stream. The fi
42、rst entry in the list is the top of the label stack and the last entry is the bottom of the label stack. Version: 1 Extends: None 6.1 Properties 6.1.1 MPLS Label Stack Property Name: MPLS Label Stack PropertyID: stack (0x0001) Description: This property corresponds to a stack of MPLS labels Type: Su
43、b-list of integer Possible values: Any legal MPLS label Default: Provisioned Defined in: Local Control Characteristics: Read/Write 6.2 Events None. 6.3 Signals None. 6.4 Statistics None. 6.5 Error codes None. 6.6 Procedures 6.6.1 Label assignment Label assignment relates to the binding of a particul
44、ar label to a H.248 stream of an ephemeral termination. This property can be applied to ephemeral terminations, which use an MPLS encapsulation. The MG prepends the label stack onto the MPLS packets (so-called “labelled packet“, see clause 3.3 of IETF RFC 3031) before sending them out of the context
45、. ITU-T Rec. H.248.54 (08/2007) 5 Appendix I Some examples for MPLS network architectures (This appendix does not form an integral part of this Recommendation) I.1 Introduction This appendix illustrates some examples of MG involvement in MPLS network architectures. I.2 H.248 MG as a MPLS edge node T
46、he H.248 MG may be connected to MPLS domains in various ways. In this case, the MG acts as a MPLS edge node (see IETF RFC 3031), see Figure I.1. Subsequent MPLS nodes within the MPLS domain could be, for instance, MPLS label switching routers (LSR), i.e., the H.248 MG would then peer with one or mul
47、tiple LSRs. Another example is a peering configuration of the H.248 MG with a label switched hop. Figure I.1 H.248 MG as MPLS edge node The H.248 MG as MPLS edge node generally provides both the MPLS ingress node and the MPLS egress node functions in case of services with bidirectional communication
48、. The LSPs of the MPLS domain, which are terminated at the H.248 MGs, may be provisioned. Other LSPs in the MPLS domain could be dynamically controlled (signalled). The MGC binds a particular H.248 stream/termination to a LSP. 6 ITU-T Rec. H.248.54 (08/2007) I.3 LSPs as aggregates for MG-to-MG traff
49、ic Aggregation is a basic MPLS concept, see clause 3.20 of IETF RFC 3031. Such aggregates could be used for MG-to-MG traffic (Figure I.2, Note 1). The relation of a label to an aggregate is detailed in IETF RFC 3031. The MGC binds (Figure I.2, Note 2) a H.248 stream/termination to an aggregate via the stack property. Figure I.2 LSPs used for aggregated MG-to-MG traffic ITU-T Rec. H.248.54 (08/2007) 7 Bibliography b-ETSI TS 102 333 ETSI TS 102 333 v1.2.0 (2008),
