1、 International Telecommunication Union ITU-T H.248.56TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Corrigendum 1(03/2009) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Gateway control protocol: Packages for virtual private network suppo
2、rt Corrigendum 1: VLAN package clarifications Recommendation ITU-T H.248.56 (2007) Corrigendum 1 ITU-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 multiplexin
3、g and synchronization H.220H.229 Systems aspects H.230H.239 Communication procedures H.240H.259 Coding 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 servi
4、ces H.350H.359 Quality of service architecture for audiovisual and multimedia services H.360H.369 Supplementary 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 mult
5、imedia systems and services H.510H.519 Mobile multimedia collaboration applications and services H.520H.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.559Mobi
6、le multimedia collaboration inter-working procedures H.560H.569 BROADBAND, TRIPLE-PLAY AND ADVANCED MULTIMEDIA SERVICES Broadband multimedia services over VDSL H.610H.619 Advanced multimedia services and applications H.620H.629 IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV General aspects H.700
7、H.719 IPTV terminal devices H.720H.729 IPTV middleware H.730H.739 IPTV application event handling H.740H.749 IPTV metadata H.750H.759 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 Recommend
8、ations. Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) i Recommendation ITU-T H.248.56 Gateway control protocol: Packages for virtual private network support Corrigendum 1 VLAN package clarifications Summary Recommendation ITU-T H.248.56 defines H.248 packages for virtual private network (VPN) support a
9、nd focuses on Ethernet-based virtual local area networks, representing a network-based layer 2 VPN type. Corrigendum 1 provides the following clarifications for the VLAN package version 1: value range 0 to 4095 of property VLAN tags used for VLAN tagging; value 4096 of property VLAN tags defines the
10、 semantic for “no VLAN tagging“; and default values for the two package properties may be defined via configuration management. Source Corrigendum 1 to Recommendation ITU-T H.248.56 (2007) was approved on 16 March 2009 by ITU-T Study Group 16 (2009-2012) under Recommendation ITU-T A.8 procedure. ii
11、Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent
12、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 every four years, establishes t
13、he 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 purview, the necessary standards a
14、re 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 voluntary. However, the Recommenda
15、tion 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 negative equivalents are use
16、d 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 the use of a claimed Intellec
17、tual 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 Recommendation, ITU had not received
18、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 http:/www.itu.int/ITU-T/ipr/. I
19、TU 2009 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) 1 Recommendation ITU-T H.248.56 Gateway control protocol: Packages for virtual private network support Corrigen
20、dum 1 VLAN package clarifications Modifications introduced by this corrigendum are shown in revision marks. Unchanged text is replaced by ellipsis (). Some parts of unchanged text (clause numbers, etc.) may be kept to indicate the correct insertion points. 1.1 General VPN support for H.248 physical
21、terminations is in principle possible with H.248 (see, e.g., b-ITU-T Rec. H.248.21), but out of scope of this Recommendation because, e.g., there is not any explicit VPN-ID on bearer level. The edge of a VPN could be further distributed in customer edge (CE) and provider edge (PE) VPN network elemen
22、ts, see clause 5.2.1 of ITU-T Y.1311 (or ITU-T G.8011.2/Y.1307.2 for Ethernet-based VPNs). The H.248 MG may provide a “customer“ edge VPN function, but also a collapsed CE/PE VPN edge function. Corrigendum 1 provides the following clarifications for the VLAN package version 1: Value range 0 to 4095
23、of property VLAN tags used for VLAN tagging; Value 4096 of property VLAN tags defines the semantic for “no VLAN tagging“; and Default values for the two package properties may be defined via configuration management. 1.2.1 Ethernet VLAN Traffic separation for frames belonging to different VLANs acro
24、ss a shared infrastructure is achieved by inserting a tag with a VLAN identifier (VID) into each frame. A VID must be assigned for each VLAN (1 to 40956) and must be globally unique within the same physical infrastructure. One of the drawbacks to this approach is that customers also use VLANs within
25、 their own network, which introduces VID allocation and limitation issues. To solve this problem, a second IEEE 802.1Q-tag can be appended to customer IEEE 802.1Q-tagged packets that enter the providers network (Q-in-Q as defined in IEEE 802.1ad). This separates the providers VLAN space from the cus
26、tomers VLAN space and allows customers to use whatever VIDs they want. 2 Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) 2 References ITU-T H.248.1 Recommendation ITU-T H.248.1 (2005), Gateway control protocol: Version 3. ITU-T H.248.52 Recommendation ITU-T H.248.52 (2008), Gateway control protocol: QoS
27、support packages. ITU-T Y.1311 Recommendation ITU-T Y.1311 (2002), Network-based VPNs Generic architecture and service requirements. 4 Abbreviations and acronyms PPVPN Provider Provisioned Virtual Private Network SDL Specification and Description Language TCI Tag Control Information 6.1 Properties 6
28、.1.1 VLAN tags Possible values: 0 to 4096 See clause 6.6.6 for a description of the 4096 value. Default: 4096 (indicating “off“) unless provisioned otherwiseNone (see also clause 6.6.5). A provisioned default value corresponds to one or two VLAN tags, dependent on flat or stacked VLAN usage. Defined
29、 in: LocalC control Characteristics: Read/write 6.1.2 Ethernet priority Possible values: 0 to 7 Default: Provisioned None (see also clause 6.6.5). Defined in: LocalC control Characteristics: Read/write Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) 3 6.6 Procedures This package can be applied to ephemer
30、al terminations where the MG is usesing an Ethernet encapsulation on the interface (compliant to IEEE 802.1p, IEEE 802.1Q and IEEE 802.1ad). For terminations where the properties are set, the MG adds the given VLAN tag(s) and priorities to the Ethernet encapsulated media flow prior to sending it out
31、 of the context. 6.6.2 QoS marking The MGC marks the priority of all egress Ethernet frames of an ephemeral termination by signalling a correspondent priority value to the MG. NOTE The function of QoS marking is possible for many packet-switched bearer technologies (see also ds package in ITU-T H.24
32、8.52). 6.6.4 Unsuccessful scenarios This clause is relevant only when both package properties are used. The Ethernet is either used as a flat or as a stacked VLAN. The sublist of possible values of both properties has then either one or two list items. The size of both sublists must be the same. Dif
33、ferent sublist sizes identify an incorrect signalling of the property values. The MG shall reply with error code #473 “Conflicting Property Values“ or code #454 (“No such parameter value in this package“) in such a case. 6.6.5 Default values for properties The default value of vlan/tags or vlan/pri
34、will be applied if the appropriate property is missing from the MGC command. In case both properties are absent, Ethernet frames are sent out of the context untagged.There are no default property values defined by this Recommendation. The primary reason is that a single MG could be connected to mult
35、iple VLANs, and every individual VLAN may use a different value range for VLAN tags and/or priorities. The MG VLAN tagging behaviour is summarized in Table 2 (and illustrated in Annex A by a formal specification using SDL): Table 2 VLAN marking using vlan version 1 package H.248 property usage Seman
36、tic vlan/pri vlan/tags Action Sent Value smaller than 4096 sent Apply VLAN tagging accordingly Sent Not sent (use provisioned default value) Apply VLAN tagging accordingly Not sent (use provisioned default value) Value smaller than 4096 sent Apply VLAN tagging accordingly Not sent Not sent Do not ap
37、ply VLAN tagging Sent or not sent Value 4096 sent Do not apply VLAN tagging 6.6.6 Turning off VLAN tagging The MGC may turn off “VLAN tagging“ by signalling a vlan/tags value of 4096 (see Figure A.1). The MG shall not insert any 802.1Q header in the Ethernet frame. The MG does not consider the vlan/
38、pri property value in this case. 4 Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) The MG and MGC shall not include the value 4096 as part of a stacked VLAN value; i.e., both the following vlan/tags values are illegal: vlan/tags = 4096, 100 ; illegal stacked VLAN with “off“ vlan/tags = 100, 4096 ; illega
39、l stacked VLAN with “off“ Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) 5 Annex A SDL specification for processing of vlan properties (This annex forms an integral part of this Recommendation) This annex provides an example SDL specification for the processing of the vlan properties by the MG. The SDL
40、chart in Figure A.1 illustrates an example logic for unstacked VLANs. Processingvlan Propertiesvlan/tags:sent?vlan/pri:sent?Novlan/tags= 4096?Yesvlan/tags= DefaultYes= provisioned value or 4096vlan/pri:sent?Novlan/pri= DefaultNoApply VLANtaggingYes= provisioned value!Turn OFF VLAN taggingYesEndvlan/
41、tags= signalled valuevlan/pri= signalled valueNoFigure A.1 Processing of vlan properties Example logic using SDL for unstacked VLANs 6 Rec. ITU-T H.248.56 (2007)/Cor.1 (03/2009) Bibliography b-ITU-T H.248.21 Recommendation ITU-T H.248.21 (2004), Gateway control protocol: Semi-permanent connection ha
42、ndling package. b-IETF RFC 2764 IETF RFC 2764 (2000), A Framework for IP Based Virtual Private Networks. b-ETSI TS 102 333 ETSI TS 102 333 (2004), Gate control protocol. Printed in Switzerland Geneva, 2009 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General ta
43、riff principles Series E Overall network operation, telephone service, service operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services
44、digital network Series J Cable networks and transmission of television, sound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, includ
45、ing TMN and network maintenance Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Terminals and subjective and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission
46、 Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
