1、 International Telecommunication Union ITU-T Y.2058TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2011) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Frameworks and functional architecture models Roadmap for IPv6 mig
2、ration from the perspective of the operators of next generation networks Recommendation ITU-T Y.2058 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.199 Services, applications an
3、d middleware Y.200Y.299 Network aspects Y.300Y.399 Interfaces 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
4、 Y.1100Y.1199 Architecture, access, network capabilities and resource 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
5、IPTV over NGN Y.1900Y.1999 NEXT GENERATION NETWORKS Frameworks and functional architecture models Y.2000Y.2099Quality 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
6、Y.2250Y.2299 Numbering, naming and addressing Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Smart ubiquitous networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999 Future networ
7、ks Y.3000Y.3099 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T Y.2058 (11/2011) i Recommendation ITU-T Y.2058 Roadmap for IPv6 migration from the perspective of the operators of next generation networks Summary Recommendation ITU-T Y.2058 specifies multiple phases
8、 for next generation network (NGN) operators to migrate from an Internet protocol version 4 (IPv4)-based NGN to an Internet protocol version 6 (IPv6)-based NGN. The migration includes five phases from a pure IPv4-based NGN to a pure IPv6-based NGN. General functional requirements of migration are gi
9、ven as are specific functional requirements for each phase. History Edition Recommendation Approval Study Group 1.0 ITU-T Y.2058 2011-11-29 13 Keywords IPv6, IPv6-based NGN, IPv6 migration, NGN, NGN operator. ii Rec. ITU-T Y.2058 (11/2011) FOREWORD The International Telecommunication Union (ITU) is
10、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 organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing R
11、ecommendations on them with a view to standardizing 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.
12、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 are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression Admi
13、nistration is used for conciseness to indicate both 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 co
14、mpliance 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 used to express requirements. The use of such words does not suggest that compliance with the Recommendation is
15、 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 Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Int
16、ellectual 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 notice of intellectual property, protected by patents, which may be required to implement this Recommendatio
17、n. 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/. ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without
18、 the prior written permission of ITU. Rec. ITU-T Y.2058 (11/2011) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Features of IPv6 migration in NGNs 2 6.1
19、Communication scenarios in IPv6 migration for NGN operators 2 6.2 Available transition mechanisms for NGN operator deployment 3 6.3 Function architecture of NGNs in the IPv6 migration period 5 7 Phases of IPv6 migration in NGNs . 6 7.1 Phase 0: NGN with IPv4 6 7.2 Phase 1: Connecting IPv6-based NGNs
20、 across an IPv4-based NGN . 7 7.3 Phase 2: Connecting IPv6-based NGNs and IPv4-based NGNs across a dual-stack NGN 8 7.4 Phase 3: Connecting IPv4-based NGNs through IPv6-based NGNs . 9 7.5 Phase 4: Fully migrated IPv6-based NGN . 9 8 Functional requirements of IPv6 migration for NGN operators . 10 8.
21、1 General functional requirements to support IPv6 migration for NGN operators . 10 8.2 Functional requirements of each IPv6 migration phase for NGN operators 11 9 Security Considerations 13 Bibliography. 14 Rec. ITU-T Y.2058 (11/2011) 1 Recommendation ITU-T Y.2058 Roadmap for IPv6 migration from the
22、 perspective of the operators of next generation networks 1 Scope The objective of this Recommendation is to specify multiple phases for NGN operators to migrate from an IPv4-based NGN to an IPv6-based NGN. The scope of this Recommendation includes: identification of IPv6 migration phases for NGN op
23、erators; IPv6 migration scenarios of each phase for NGN operators; functional requirements of each phase for NGN operators. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At
24、 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 the possibility of applying the most recent edition of the Recommendations and other references listed b
25、elow. 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 Recommendation. ITU-T Y.2001 Recommendation ITU-T Y.2001 (2004), General overview of NGN. ITU-T Y.2011
26、 Recommendation ITU-T Y.2011 (2004), General principles and general reference model for Next Generation Networks. ITU-T Y.2012 Recommendation ITU-T Y.2012 (2006), Functional requirements and architecture of the NGN release 1. ITU-T Y.2053 Recommendation ITU-T Y.2053 (2008), Functional requirements f
27、or IPv6 migration in NGN. ITU-T Y.2091 Recommendation ITU-T Y.2091 (2007), Terms and definitions for Next Generation Networks. ITU-T Y.2701 Recommendation ITU-T Y.2701 (2007), Security requirements for NGN release 1. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following te
28、rms defined elsewhere: 3.1.1 host b-ITU-T Y.1540: A computer that communicates using the Internet protocols. A host implements routing functions (i.e., it operates at the IP layer) and may implement additional functions including higher layer protocols (e.g., TCP in a source or destination host) and
29、 lower layer protocols (e.g., ATM). 3.1.2 router b-ITU-T Y.1540: A host that enables communication between other hosts by forwarding IP packets based on the content of their IP destination address field. 2 Rec. ITU-T Y.2058 (11/2011) 3.1.3 IPv6-based NGN b-ITU-T Y.2051: This refers to NGN that suppo
30、rts addressing, routing protocols, and services associated with IPv6. An IPv6-based NGN shall recognize and process the IPv6 headers and options, operating over various underlying transport technologies in the transport stratum. 3.2 Terms defined in this Recommendation This Recommendation defines th
31、e following terms: 3.2.1 carrier grade NAT (CGN): A network address translation (NAT) device deployed in a carrier network. It translates packets between different IP address namespaces. It may be integrated with tunnel functions too. 3.2.2 dual-stack NGN: This refers to an NGN that supports address
32、ing, routing protocols, and services associated with both IPv4 and IPv6. A dual-stack NGN shall recognize and process both IPv4 and IPv6 headers and options, operating over various underlying transport technologies in the transport stratum. Translation services may be provided in a dual-stack NGN to
33、 enable intercommunication between IPv4 and IPv6. 3.2.3 NGN operator: An entity that provides NGN connections. It provides and maintains NGN infrastructure. Either, an IPv4-based NGN, an IPv6-based NGN, or both may be provided. 4 Abbreviations and acronyms This Recommendation uses the following abbr
34、eviations and acronyms: 6PE IPv6 Provider Edge Router CGA Cryptographically Generated Addresses CGN Carrier Grade NAT DNS Domain Name System IPSec Internet Protocol Security IPv4 Internet Protocol version 4 IPv6 Internet Protocol version 6 MPLS Multi-Protocol Label Switching NAT Network Address Tran
35、slation NGN Next Generation Network 5 Conventions None. 6 Features of IPv6 migration in NGNs The primary purpose of IPv6 migration solutions is to allow NGN operators to provide IPv6 networks and IPv6-based services whilst ensuring the continuation of IPv4 networks and IPv4-based services. They also
36、 allow IPv4 and IPv6 networks to communicate with each other. 6.1 Communication scenarios in IPv6 migration for NGN operators During the IPv6 migration period, NGN operators need to support the following communication scenarios, in addition to some basic IPv6 communications. Some of these scenarios
37、may be optional during the different migration phases, which are described in clause 6. Rec. ITU-T Y.2058 (11/2011) 3 Scenario A: A legacy IPv4 host communicates with a legacy IPv4 host or an IPv4 application on a dual-stack host. It should continue to receive support until phase 4, when the network
38、 has fully migrated to an IPv6-based NGN. The basic function requires IPv4 routing and forwarding. Scenario B: An IPv6-only host communicates with an IPv6-only host or an IPv6 application on a dual-stack host. It should be supported throughout IPv6 migration starting from the beginning, phase 1. The
39、 basic function requires IPv6 routing and forwarding. Scenario C: A legacy IPv4 host communicates with a legacy IPv4 host or an IPv4 application on a dual-stack host through an IPv6 network. It should be supported in phase 3, and may be supported in phase 2. The basic function requires IPv4-over-IPv
40、6 tunnelling. Scenario D: An IPv6-only host communicates with an IPv6-only host or an IPv6 application on a dual-stack host through an IPv4 network. It should be supported in phase 1, and may be supported in phase 2. The basic function requires IPv6-over-IPv4 tunnelling. Scenario E: An IPv6-only hos
41、t communicates with an IPv4-only host. It should be supported in phases 1, 2, 3 and 4. The basic function requires the translation of addresses and protocols. Scenario F: A legacy IPv4 host communicates with an IPv6-only host. It should be supported in phases 1, 2, 3 and 4. The basic function requir
42、es the translation of addresses and protocols. 6.2 Available transition mechanisms for NGN operator deployment 6.2.1 Available transition mechanisms ITU-T Y.2053 describes three basic approaches for interworking and migration: dual IP layer (dual stack), configured tunnelling and network address and
43、 protocol translation. Additionally, application level gateways or proxy servers can be adopted based on each application. These basic transition mechanisms meet different requirements and scenarios during the migration phases. NGN operators may deploy the different combinations of these existing tr
44、ansition mechanisms in their NGN according to their requirements in each phase. Furthermore, the exhaustion of global public IPv4 addresses is getting closer and closer. Many network operators are already suffering from the shortage of global public IPv4 addresses. Many NAT devices have been deploye
45、d so that private IPv4 addresses are used more extensively. The usage of private IPv4 addresses does not solve the address exhaustion issue. It may slow the exhaustion but with many side effects and issues. However, during the IPv6 migration, private IPv4 addresses may be used to provide IPv4 access
46、 services. CGNs can be deployed in the NGN so that public IPv4 addresses can be shared. 6.2.2 Combined transition mechanisms for NGN operators deployment The combination of existing transition mechanisms can be deployed in the NGN to simplify the operation of end user services during the IPv4/IPv6 m
47、igration phases. The functions can be integrated with CGNs and deployed on the network side and managed/maintained by NGN operators. In phases 1 and 2, as shown in Figure 1, IPv6-over-IPv4 tunnelling may be integrated with the CGN and translation function between IPv6 and IPv4. The integrated device
48、s can be deployed at the border between the IPv4-based NGN and the IPv6-based NGN. When a dual-stack CGN receives a data packet from a dual-stack host, it firstly checks whether the packet is a normal IPv4 packet or an IPv6-over-IPv4 tunnel packet. For a normal IPv4 packet, the CGN translates the pa
49、cket source address from a CGN-scoped private IPv4 address into a public IPv4 address, and then sends it to an IPv4-based NGN. The CGN should record the IPv4-IPv4 address mapping information for inbound packets, just like a normal NAT. For an IPv6-over-IPv4 tunnel packet, the CGN needs to 4 Rec. ITU-T Y.2058 (11/2011) de-encapsulate it into the original IPv6 packet and then send it to an IPv6-based NGN. If the destination address of the original IPv6 packet is an IPv4-embedded address, this IPv6
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