1、 International Telecommunication Union ITU-T Q.3313TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2012) SERIES Q: SWITCHING AND SIGNALLING Signalling requirements and protocols for the NGN Resource control protocols Signalling protocols and procedures relating to flow state aware QoS control in
2、 a bounded subnetwork of a next generation network Recommendation ITU-T Q.3313 ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE
3、ISDN Q.60Q.99 CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS Q.100Q.119 SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4, 5, 6, R1 AND R2 Q.120Q.499 DIGITAL EXCHANGES Q.500Q.599 INTERWORKING OF SIGNALLING SYSTEMS Q.600Q.699 SPECIFICATIONS OF SIGNALLING SYSTEM No. 7 Q.700Q.799 Q3 INTERFACE Q.800Q.849 DIGITAL
4、 SUBSCRIBER SIGNALLING SYSTEM No. 1 Q.850Q.999 PUBLIC LAND MOBILE NETWORK Q.1000Q.1099 INTERWORKING WITH SATELLITE MOBILE SYSTEMS Q.1100Q.1199 INTELLIGENT NETWORK Q.1200Q.1699 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR IMT-2000 Q.1700Q.1799 SPECIFICATIONS OF SIGNALLING RELATED TO BEARER INDEPENDENT C
5、ALL CONTROL (BICC) Q.1900Q.1999 BROADBAND ISDN Q.2000Q.2999 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR THE NGN Q.3000Q.3999 General Q.3000Q.3029 Network signalling and control functional architecture Q.3030Q.3099 Network data organization within the NGN Q.3100Q.3129 Bearer control signalling Q.3130Q.
6、3179 Signalling and control requirements and protocols to support attachment in NGN environments Q.3200Q.3249 Resource control protocols Q.3300Q.3369Service and session control protocols Q.3400Q.3499 Service and session control protocols supplementary services Q.3600Q.3649 NGN applications Q.3700Q.3
7、849 Testing for NGN networks Q.3900Q.3999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T Q.3313 (02/2012) i Recommendation ITU-T Q.3313 Signalling protocols and procedures relating to flow state aware QoS control in a bounded subnetwork of a next generation networ
8、k Summary Recommendation ITU-T Q.3313 specifies the signalling format and procedures for the flow state aware (FSA) transfer capability in a bounded subnetwork of a next generation network (NGN). The FSA transfer capability provides QoS controls that operate on a per-flow basis, allowing flows withi
9、n a bounded subnetwork of an NGN to receive different treatments depending on signalled parameters. These parameters are requested using in-band signalling. The parameters contained in these signals are included in the “flow state“ maintained on each flow (or each aggregate flow), at each FSA node.
10、Service options that may be selected include the requested support of the highest available end-to-end rate for data transfer, assuming some source-to-receiver forwarding paths are entirely within the bounded subnetwork of an NGN. The focus of this Recommendation is on broadband (including mobile) s
11、ervice access scenarios typically involving restricted bandwidth shared by many flows. In such circumstances, customer satisfaction, when there is temporary congestion, may be best handled by applying flow preferences and QoS differently for each customer and not simply on the type of media. This le
12、ads to the notion of customised QoS supported partly by signalling and partly through web-based tools. These concepts may also be applied to flow aggregates, with associated signalling support acting at the aggregate level between aggregation end-points, as defined in Recommendation ITU-T Y.2121. Th
13、e customization of aggregates in this Recommendation is limited to the notions of preference priority and FSA transfer capability. History Edition Recommendation Approval Study Group 1.0 ITU-T Q.3313 2012-02-22 11 Keywords Available rate, broadband service access, flow state, flow state aware (FSA),
14、 in-band signalling, NGN, QoS. ii Rec. ITU-T Q.3313 (02/2012) 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
15、-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 every four y
16、ears, 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 purview, the ne
17、cessary 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 voluntary. Howe
18、ver, 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 negative
19、 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 the use o
20、f 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 Recommendation, I
21、TU 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 http:/www.i
22、tu.int/ITU-T/ipr/. ITU 2012 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 Q.3313 (02/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Ter
23、ms defined in this Recommendation . 2 4 Abbreviations and acronyms 3 5 Conventions 4 6 High-level description 4 7 Protocol description 5 7.1 QoS parameters related to flow-based QoS management 5 7.2 Message sequences related to FSA transport service set up and clear down. 6 7.3 Procedures and format
24、 of layer 2 FSA Ethertype packets 8 8 Security considerations and requirements 12 8.1 Authentication 12 8.2 Authorization 12 8.3 Data confidentiality 13 8.4 Data integrity 13 8.5 Accountability 13 8.6 Availability and accessibility . 13 8.7 Privacy 13 8.8 Protection against network attacks, from wit
25、hin or outside . 13 9 State diagrams for FSA signalling edge functions at origination and destination 13 9.1 Origination state machine . 13 9.2 Termination state machine . 14 9.3 Signalling renegotiation 15 10 FSA QoS manager 15 Annex A Rules for encoding floating point rates . 17 A.1 AR and GR Enco
26、ding floating point . 17 Appendix I Mapping FSA services to ITU-T Y.1221 transfer capabilities 18 I.1 Maximum rate service (MRS) 18 I.2 Available rate service (ARS) 18 Appendix II Example of a bounded subnet isolated by proxies . 20 Rec. ITU-T Q.3313 (02/2012) 1 Recommendation ITU-T Q.3313 Signallin
27、g protocols and procedures relating to flow state aware QoS control in a bounded subnetwork of a next generation network 1 Scope This Recommendation provides the signalling format and procedures for the flow state aware (FSA) transfer capability in a bounded subnetwork of a next generation network (
28、NGN). The FSA transfer capability provides QoS controls that operate on a per-flow basis, allowing flows within a bounded subnetwork of an NGN to receive different treatments depending on signalled parameters. These parameters are requested using in-band signalling. The parameters contained in these
29、 signals are included in the “flow state“ maintained on each flow (or each aggregate flow), at each FSA node. Out of scope are any FSA edge functions at the network domain boundaries needed for interworking between two FSA networks, where one uses in-band signalling exclusively for all FSA service s
30、upport and the other uses both out-of band signalling (for resource reservation and clear down) and in-band signalling (to establish the agreed flow state). FSA signalling must not be used in the core network as it impacts on the scalability. 2 References The following ITU-T Recommendations and othe
31、r references contain 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
32、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 Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document,
33、 the status of a Recommendation. ITU-T Y.1221 Recommendation ITU-T Y.1221 (2010), Traffic control and congestion control in IP-based networks. ITU-T Y.2111 Recommendation ITU-T Y.2111 (2011), Resource and admission control functions in next generation networks. ITU-T Y.2121 Recommendation ITU-T Y.21
34、21 (2008), Requirements for the support of flow-state-aware transport technology in NGN. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 available rate service (ARS) ITU-T Y.2121: The name of one of the flow state aware (FSA) transport
35、services. ARS is primarily for applications that can flexibly adapt to the current available capacity and can quickly adjust their sending rate as the available capacity changes. 3.1.2 flow ITU-T Y.2121: A unidirectional sequence of packets with the property that, along any given network link, a flo
36、w identifier has the same value for every packet. 3.1.3 flow admission control ITU-T Y.2121: The determination, for authorised requests, of whether or not to accept a given flow. 3.1.4 flow aggregate ITU-T Y.2121: A hierarchical flow construct that is associated with a group of flows. The carried fl
37、ows may extend beyond the flow aggregate. Except for the end nodes, 2 Rec. ITU-T Q.3313 (02/2012) flow aggregate forwarders in general do not know that they are carrying flows within the flow aggregate. All packets belonging to a given flow aggregate are commonly routed between aggregation end-point
38、s. 3.1.5 flow state ITU-T Y.2121: A set of values stored per flow identifier at each flow state aware node. This set of values will determine controls applied on a per-flow basis, dealing with forwarding rate, delay, and congestion recovery. 3.1.6 flow state aware node ITU-T Y.2121: A network node t
39、hat is capable of maintaining flow state and applying per-flow QoS controls, based on recognising flow identifier and associated signals. 3.1.7 in-band signalling ITU-T Y.2121: A mode of signalling where the signalling messages are within the flow of the data packets, and follow a path that is tied
40、to the data packets. Signalling messages are routed only through nodes that are in the data path. 3.1.8 maximum rate service (MRS) ITU-T Y.2121: The name of one of the flow state aware (FSA) transport services. MRS is for applications that want packet loss characteristics to be sufficient for stream
41、ed services as soon as possible but are unwilling to wait or be rejected by network admission control if network resource for this target QoS is not available immediately. 3.1.9 out-of-band signalling ITU-T Y.2121: A mode of signalling where the signalling messages are not in the same flow of the da
42、ta packets, and may follow a different path to the data packets and are routed to one or more nodes that are not in the data path. 3.1.10 QoS structure ITU-T Y.2121: The block of QoS signalling information in a signalling packet. 3.2 Terms defined in this Recommendation This Recommendation defines t
43、he following terms: 3.2.1 bounded subnet: In the context of Recommendation ITU-T Q.3313, a flow state aware (FSA) bounded subnet is a network section where all network nodes support that Recommendation. 3.2.2 ethertype: An Ethertype is a 16 bit identifier assigned by the IEEE to designate a layer 3
44、protocol being carried over Ethernet. NOTE The Ethertype for Recommendation ITU-T Q.3313 is 0x22EF. 3.2.3 flow identifier: A vector comprising the values of a number of elements taken from the header fields of the incoming packets which identify the flow. The flow identifier for a flow within a sing
45、le FSA network is unique. 3.2.4 flow state aware proxy: A function that provides the origin and/or termination of the flow state aware end-to-end signalling path, and participates in requests and responses on behalf of a user application or management action. NOTE Flow state aware proxy may be locat
46、ed, for example, in a user end-system or at a network edge node where it serves as the signalling end-point of multiple users and associated applications. 3.2.5 preference priority: A parameter used to determine whether to admit a flow or scale its rate in case of network overload. NOTE In network o
47、verload state, an MRS flow with the lower preference priority may be rejected while the one with a higher preference priority level will still be admitted, or for ARS flows, preference priority should be used to scale the rate of the flow with respect to other ARS flows. Rec. ITU-T Q.3313 (02/2012)
48、3 3.2.6 proxy: In the context of Recommendation ITU-T Q.3313, proxy is the name for a flow state aware signalling edge function, a process which encapsulates incoming traffic and inserts ITU-T Q.3313 signalling in one direction and in the other direction de-encapsulates and deletes ITU-T Q.3313 sign
49、alling. NOTE This process can be located inside a users end-system or exist as a separate system in the data path. 3.2.7 RESPONSETIMEOUT: The maximum period that a signal packet of type request, renegotiate, or close has not been responded to. NOTE The signalling packet should be repeated a second and third time before the ITU-T Q.3313 state is dropped. 3.2.8 signal packet: Signal packets are used to carry signalling information across the bounded subnet where flow state aware (FSA) support i
