1、 International Telecommunication Union ITU-T Y.2601TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (12/2006) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Fundamental characteristics and requirements of future packet base
2、d networks ITU-T Recommendation Y.2601 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
3、and protocols Y.400Y.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 r
4、esource management 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 architectur
5、e models Y.2000Y.2099 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.24
6、99 Network control 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.2601 (12/2006) i ITU-T Recommendation Y.2601 Fundamental characteristics and requirements of future
7、 packet based networks Summary This Recommendation provides fundamental characteristics of a future packet based network (FPBN). This Recommendation provides user plane, control plane and management plane requirements for the architecture of an FPBN comprised of transport stratum packet based path l
8、ayer networks as defined in G.805, G.809, X.200 and Y.2011. Source ITU-T Recommendation Y.2601 was approved on 14 December 2006 by ITU-T Study Group 13 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. Y.2601 (12/2006) FOREWORD The International Telecommunication Union (ITU) is
9、 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 questions and issuing Recommendations on them with a view to standardizin
10、g 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 Recommendations on these topics. The approval of ITU-T Recommendations is covered b
11、y 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 Recommendation, the expression “Administration“ is used for conciseness to indicate b
12、oth 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 applicability) and compliance with the Recommendation is achieved when
13、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 with the Recommendation is required of any party. INTELLECTUAL PROPERTY
14、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 applicability of claimed Intellectual Property Rights, whether asserted by
15、 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 implement this Recommendation. However, implementers are cautioned that th
16、is 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/. ITU 2007 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Re
17、c. Y.2601 (12/2006) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 4 Abbreviations 2 5 Future packet based networks. 3 6 Fundamental characteristics . 3 7 Requirements 4 7.1 Addressing requirements 4 7.2 Control related requirements 4 7.3 QoS related requirements . 4 7.4 Network perform
18、ance management (PM) related requirements 5 7.5 Protection related requirements 5 7.6 Payload related requirements . 5 7.7 Operations, administration and maintenance (OAM) related requirements. 5 7.8 Security related requirements. 6 7.9 Control plane requirements 6 7.10 Management plane requirements
19、 6 7.11 Basic transport stratum service requirements. 6 7.12 Enhanced transport stratum service requirements 6 Appendix I Some problems with current packet based networks. 7 I.1 Issues facing network operators . 7 BIBLIOGRAPHY 9 ITU-T Rec. Y.2601 (12/2006) 1 ITU-T Recommendation Y.2601 Fundamental c
20、haracteristics and requirements of future packet based networks 1 Scope This Recommendation provides fundamental characteristics of a future packet based network (FPBN). This Recommendation provides user plane, control plane and management plane requirements for the architecture of an FPBN comprised
21、 of transport stratum packet based path layer networks as defined in G.805, G.809, X.200 and Y.2011. 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 publicatio
22、n, 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 edition of the Recommendations and other references listed below. A list of the cur
23、rently 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. G.805 ITU-T Recommendation G.805 (2000), Generic functional architecture of transport networks. G.809 ITU-T R
24、ecommendation G.809 (2003), Functional architecture of connectionless layer networks. X.200 ITU-T Recommendation X.200 (1994) | ISO/IEC 7498-1:1994, Information technology Open Systems Interconnection Basic Reference Model: The basic model. Y.2011 ITU-T Recommendation Y.2011 (2004), General principl
25、es and general reference model for Next Generation Networks. Y.2111 ITU-T Recommendation Y.2111 (2006), Resource and admission control functions in Next Generation Networks. 3 Definitions This Recommendation uses and defines the following terms: 3.1 absolute QoS: See Y.2111. 3.2 access group: See G.
26、805. 3.3 address: An address is the identifier for a specific termination point and is used for routing to this termination point. 3.4 connection: See G.805. 3.5 control plane: See Y.2011. 3.6 flow: See G.809. 3.7 flow domain: See G.809. 3.8 identifier: An identifier is a series of digits, character
27、s and symbols or any other form of data used to identify subscriber(s), user(s), network element(s), function(s), network entity(ies) providing services/applications, or other entities (e.g., physical or logical objects). 2 ITU-T Rec. Y.2601 (12/2006) NOTE Identifiers can be used for registration or
28、 authorization. They can be either public to all networks, shared between a limited number of networks or private to a specific network (private identifiers are normally not disclosed to third parties). 3.9 user plane: A classification for objects whose principal function is to provide transfer of e
29、nd-user information: user information may be user-to-user content, or private user-to-user data. 3.10 importance: Importance is the survivability of a given packet compared to all other packets when the network has insufficient resources to service all the traffic. NOTE The importance of a given pac
30、ket is independent of the delay requirements (urgency) of that packet. 3.11 management plane: See Y.2011. 3.12 off-path: Off-path in a connection-oriented network means it is using a separate trail. Off-path in a connectionless network means it is using a separate server layer trail. 3.13 relative Q
31、oS: See Y.2111. 3.14 subnetwork: See G.805. 3.15 trail: See G.805. 3.16 urgency: Urgency is how fast a packet must get processed in order to meet the requested QoS requirements. NOTE The urgency of a packet is conveyed in terms of the performance (delay) it requires and a packets urgency is independ
32、ent of the survivability (importance) of that packet. 4 Abbreviations This Recommendation uses the following abbreviations and acronyms: ATM Asynchronous Transfer Mode CAPEX Capital Expenditure cl-ps Connectionless packet switched co-cs Connection-oriented circuit switched co-ps Connection-oriented
33、packet switched DoS Denial of Service FPBN Future Packet Based Network FR Frame Relay IP Internet Protocol mp-t-mp Multipoint-to-multipoint MTU Maximum Transmission Unit OAM Operations, Administration and Maintenance OPEX Operational Expenditure PHB Per-Hop Behaviour PM Performance Management PSTN P
34、ublic Switched Telephone Network p-t-mp Point-to-multipoint p-t-p Point-to-point QoS Quality of Service ITU-T Rec. Y.2601 (12/2006) 3 SLA Service Level Agreement SLS Service Level Specification VPN Virtual Private Network 5 Future packet based networks Future Packet Based Networks (FPBNs) provide th
35、e topmost layer(s) of the transport stratum as defined in Y.2011. Further ITU-T Recommendations and other ITU-T documents are expected to provide more detailed requirements, architecture and protocols based on the FPBN fundamental characteristics and requirements within this Recommendation. 6 Fundam
36、ental characteristics This clause provides objectives for an FPBN in terms of the fundamental characteristics. The main objectives are provided below. An FPBN is expected to: Provide both connectionless (cl-ps) and connection-oriented (co-ps) services for multiple client types. Efficiently support p
37、oint-to-point (p-t-p) and point-to-multipoint (p-t-mp) services. Support at least absolute quality of service (QoS) in the co-ps mode (if a co-ps mode is provided). Interwork and coexist with current cl-ps and co-ps packet networks. Support arbitrary network topologies and be able to expand bandwidt
38、h, topology, number-of-customers and number-of-services incrementally. Detect, and recover from, facility and equipment failures and performance degradation as appropriate to the requirements of the service. Offer the appropriate operations, administration and maintenance (OAM) functions for each pl
39、ane. Completely secure the internal control and management plane traffic from external attack and ensure that it remains secure and stable under situations of extreme stress. Secure the management plane to prevent access to control and management functions by unauthorized users. Be able to accommoda
40、te new traffic types. Support mechanisms to allow statistical multiplexing for efficiency. Support lawful interception of FPBN services. The requirements for lawful interception in NGN are described in other ITU-T Recommendations. Support accounting functions by being able to monitor at least networ
41、k utilization and performance parameters. Provide the ability to distinguish between urgency (delay) and importance (survivability). Support services that require in-order delivery of packets. Provide harmonized and consistent means of referring to user plane access points. Provide traffic user plan
42、e defect detection and handling (OAM) that is not reliant on the control and/or management planes and is not a function of the nature of the client being transported. 4 ITU-T Rec. Y.2601 (12/2006) Support mechanisms to harmonize trail or connection setup and teardown with OAM activation and deactiva
43、tion. Support mechanisms to avoid traffic impact during reconfiguration. Attempt to keep traffic flowing while recovering from failures. Only deliver traffic from the intended source/ingress to the intended destination(s)/egress(es) except under extremely rare multiple failure conditions. Support em
44、ergency services. Be scalable and reliable. Support mechanisms to maintain the separation between user traffic flows as appropriate for the FPBN service that is being provided. Additionally, an FPBN: Should efficiently support multipoint-to-multipoint (mp-t-mp) services. Should allow a smooth migrat
45、ion from current cl-ps and co-ps packet networks. Should support logical separation of control, management and user planes. Should support off-path control and management planes. 7 Requirements This clause provides requirements based on the objectives provided in clause 6. 7.1 Addressing requirement
46、s This clause provides addressing related requirements for an FPBN. These requirements apply to the network, not necessarily to the user packet itself. An FPBN is expected to support: The identification of a packets source and its destination within the FPBN in the cl-ps mode. The identification of
47、a connections source within the FPBN in the co-ps mode at the connections destination. Additionally, an FPBN: Should support FPBN addressing that is disjoint from any client addressing. 7.2 Control related requirements This clause provides control related requirements for an FPBN. An FPBN is expecte
48、d to support: Mechanisms to safeguard against persistent (i.e., looping) traffic units in the cl-ps mode. Mechanisms to safeguard against co-ps connections containing forwarding loops. Mechanisms to ensure the integrity of the control information (e.g., header checksum). Additionally, an FPBN: Shoul
49、d facilitate the in-order delivery of the traffic unit. 7.3 QoS related requirements This clause provides QoS related requirements for an FPBN. An FPBN: May support queuing priority, which can be implicit or explicit. ITU-T Rec. Y.2601 (12/2006) 5 May support discard priority, which can be implicit or explicit. 7.4 Network performance management (PM) related requirements This clause provides PM related requirements for an FPBN.
