1、 International Telecommunication Union ITU-T Y.2059TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2012) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Frameworks and functional architecture models Functional requireme
2、nts for accessing IPv6-based next generation networks Recommendation ITU-T Y.2059 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
3、.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 Y.1100Y.1199 Archi
4、tecture, 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 IPTV over NGN Y.190
5、0Y.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 Y.2250Y.2299 Number
6、ing, naming and addressing Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Packet-based Networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999 FUTURE NETWORKS Y.3000Y.3499 CLOUD C
7、OMPUTING Y.3500Y.3999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T Y.2059 (07/2012) i Recommendation ITU-T Y.2059 Functional requirements for accessing IPv6-based next generation networks Summary Recommendation ITU-T Y.2059 provides the impact study, scenario an
8、alysis and functional requirements for the networks which are connected to the IPv6-based NGN. It involves both the access network side and the core network side of NGN. All the analysis is basically divided into two aspects, which are IPv6 connectivity and IPv4-compatible connectivity. IPv6 connect
9、ivity focuses on IPv6-only network provision which contains prefix and address allocation, configuration, etc. IPv4-compatible connectivity focuses on IPv4-to-IPv6 transition technologies that continue to provide IPv4 services to users. History Edition Recommendation Approval Study Group 1.0 ITU-T Y
10、.2059 2012-07-29 13 Keywords IPv6, IPv6 network access, NGN. ii Rec. ITU-T Y.2059 (07/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunicati
11、on 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 standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (W
12、TSA), 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 by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall
13、 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 both a telecommunication administration and a recognized operating agency. Compliance with this Rec
14、ommendation 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 all of these mandatory provisions are met. The words “shall“ or some other obligatory language s
15、uch 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 RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recomm
16、endation 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 ITU members or others outside of the Recommendation development process. As of the date of appr
17、oval 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 this may not represent the latest information and are therefore strongly urged to consult the TSB
18、patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 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 Y.2059 (07/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Ter
19、ms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 Impact on network functions for accessing the IPv6-based NGN 3 6.1 IPv6 connectivity provision 3 6.2 IPv4-compatible connectivity provision . 4 6.3 Security . 4 7 Scenarios and parame
20、ter configurations for accessing the IPv6-based NGN 5 7.1 IPv6 connectivity provisioning . 6 7.2 IPv4-compatible connectivity provision . 11 7.3 Security . 12 8 Functional requirements for access to the IPv6-based NGN 14 8.1 Transport stratum functions 14 8.2 End-user functions 15 9 Security conside
21、rations . 16 Bibliography. 17 Rec. ITU-T Y.2059 (07/2012) 1 Recommendation ITU-T Y.2059 Functional requirements for accessing IPv6-based next generation networks 1 Scope The objective of this Recommendation is to identify impacts on networks which are connected to the IPv6-based NGN, and to describe
22、 the relevant scenarios/models in order to identify the functional requirements. NGN transport stratum functions provide a series of transport and transport control functions that support the service stratum features. In IPv6, some mechanisms have been already introduced to support both transport an
23、d transport control functions in order to perform the access to the IPv6-based NGN. Along with IPv6, the devices in network also have relevant functional requirements. This Recommendation covers: identification of the impact on networks which are connected to IPv6-based NGNs; network access scenario
24、s specific to the NGN, including parameter configurations such as prefix, address and server configurations; scenarios of access network level registration in IPv6-based NGNs; functional requirements for networks which are connected to IPv6-based NGNs. 2 References The following ITU-T Recommendation
25、s and other 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 e
26、ncouraged 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
27、 document, the status of a Recommendation. ITU-T Y.2001 Recommendation ITU-T Y.2001 (2004), General overview of NGN. ITU-T Y.2051 Recommendation ITU-T Y.2051 (2008), General overview of IPv6-based NGN. ITU-T Y.2053 Recommendation ITU-T Y.2053 (2008), Functional requirements for IPv6 migration in NGN
28、. 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 terms defined elsewhere: 3.1.1 IPv6-based NGN ITU-T Y.2051: This refers to NGN that supports addressing, routing protocols, and
29、 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. 2 Rec. ITU-T Y.2059 (07/2012) 3.1.2 NAT64 b-IETF RFC 6146: A mechanism for IPv4-IPv6 transition and IPv4-IPv6
30、 coexistence. Together with DNS64, these two mechanisms allow an IPv6-only client to initiate communications to an IPv4-only server. 3.1.3 next generation network ITU-T Y.2001: A packet-based network able to provide telecommunication services and to make use of multiple broadband, (QoS)-enabled tran
31、sport technologies and in which service-related functions are independent from underlying transport-related technologies. It enables unfettered access for users to networks and to competing service providers and/or services of their choice. It supports generalized mobility which will allow consisten
32、t and ubiquitous provision of services to users. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 DNS64 (based on b-IETF RFC 6147): A mechanism for synthesizing IPv6 DNS b-IETF RFC 1035 records from IPv4 DNS records. DNS64 is used with an IPv6/IPv4 tran
33、slator to enable client-server communication between an IPv6-only client and an IPv4-only server, without requiring any changes to either the IPv6 or the IPv4 node for the class of applications that work through NATs. 3.2.2 tunnel concentrator: A function/device that terminates multiple tunnels from
34、 a user side, concentrates traffic carried by the tunnels, and forwards the traffic to a new tunnel towards a network side, so that the number of tunnels to be handled by the network is reduced. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AAAA Auth
35、entication, Authorization, Accounting and Auditing CGA Cryptographically Generated Address CPE Customer Premises Equipment DHCPv6 Dynamic Host Configuration Protocol version 6 DNS Domain Name Service DUID DHCP Unique Identifier FE Functional Entity ID Identifier IPv4 Internet Protocol version 4 IPv6
36、 Internet Protocol version 6 ISP Internet Service Provider LAN Local Area Network MAC Media Access Control NACF Network Attachment Control Function NAT Network Address Translation ND Network Discovery NGN Next Generation Network OAM Operation and Maintenance PD Prefix Delegation Rec. ITU-T Y.2059 (0
37、7/2012) 3 PPP Point-to-Point Protocol RA Router Advertisement RACF Resource and Admission Control Function RS Router Solicitation UE User Equipment VLAN Virtual Local Area Network WAN Wide Area Network 5 Conventions None. 6 Impact on network functions for accessing the IPv6-based NGN IPv6 is differe
38、nt from IPv4 in various aspects. To access the IPv6-based NGN, the basic approach is to provide IPv6 connectivity, which includes mainly prefix/address provisioning and allocation. An IPv6 address is composed of prefix and interface ID. Existing mechanisms provide different methods to configure the
39、prefixes and addresses. Besides the IPv6 connectivity, the network also needs to support the old IPv4 users to access the IPv6-based NGN. Further, IPv6 security requirements are also different from the security requirements of IPv4. This clause identifies these mechanisms and describes how they impa
40、ct network access. 6.1 IPv6 connectivity provision 6.1.1 Prefix and address space The IPv6 address is 128 bits long. The most common addressing architecture is 64 bits for the network number (prefix) and 64 bits for the host number (interface ID). IPv6 has a more complex addressing architecture than
41、 IPv4. With a huge IPv6 address space and a complex prefix structure, the following impact on network access the IPv6-based NGN should be considered. Address availability and reachability: A user can have one or more globally unique IPv6 addresses. The problems caused by a limited IPv4 address space
42、 would not exist any longer. It should be technically easy and efficient for every user who wants to obtain a globally unique IPv6 address. Users can be considered globally reachable via the obtained IPv6 address. The adoption of IPv6 addresses impacts network address translation techniques, which m
43、ay be reduced or even abandoned in IPv6 networks. In IPv6, the scope of the address is embedded in part of the address structure. Unicast addresses have three defined scopes, including link-local, unique link-local and global. Default address selection for both source and destination takes scope int
44、o account. The address scope impacts address acquisition by the user terminal, the bootstrapping sequence of customer premises equipment (CPE) interfaces, etc. Prefix structure: The address mask is used in IPv4 to distinguish the network portion from the host portion. The address mask is not used in
45、 IPv6; instead, address prefix is used to distinguish the sub-network prefix of an address. IPv6 has its own way of performing the prefix advertisement and delegation in order to organize the prefix in a manageable way for service providers or customers. User equipment should be able to easily get t
46、he prefix. 4 Rec. ITU-T Y.2059 (07/2012) 6.1.2 Prefix and address allocation mechanism IPv6 supports both stateful and stateless address configuration. The relevant mechanisms have already been standardized in IETF, including DHCPv6 b-IETF RCF 3315, neighbour discovery for IPv6 b-IETF RFC 4861, IPv6
47、 stateless address auto configuration b-IETF RFC 4862, IPv6 prefix options for DHCPv6 b-IETF RFC 3633 and a number of other RFCs and Recommendations. Prefix and address allocation mechanisms in IPv6 are different from those in IPv4. They impact the following aspects: CPE side: The CPE is a connectio
48、n point between the home network and the access/aggregation network. It may employ different prefix and address allocation mechanisms on LAN and WAN interfaces. A users network access depends greatly on the functions and features provided by the CPE. Network side: The operators can have their own wa
49、y for advertising prefixes and configuring addresses. In some cases, both stateful and stateless address configuration may be used simultaneously. Some network nodes should be aware of the IPv6 signalling in order to help and monitor the IPv6 data transport. 6.1.3 Multiple addresses One of the important features of IPv6 is that it allows multiple addresses to be assigned to an interface. The feature could be utilized in many scenarios such as mobile IPv6 and multi-homing. Besides, IPv6 addresses also hav
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