1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T Q.3713 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2017) SERIES Q: SWITCHING AND SIGNALLING, AND ASSOCIATED MEASUREMENTS AND TESTS Signalling requirements and protocols for SDN Resource control protocols Signalling
2、requirements for broadband network gateway pool Recommendation ITU-T Q.3713 ITU-T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING, AND ASSOCIATED MEASUREMENTS AND TESTS SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE Q.1Q.3 INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING Q.4Q.59 FUNCTIONS AND IN
3、FORMATION FLOWS FOR SERVICES IN THE 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
4、.799 Q3 INTERFACE Q.800Q.849 DIGITAL 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 SIGNAL
5、LING RELATED TO BEARER INDEPENDENT CALL CONTROL (BICC) Q.1900Q.1999 BROADBAND ISDN Q.2000Q.2999 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR THE NGN Q.3000Q.3709 SIGNALLING REQUIREMENTS AND PROTOCOLS FOR SDN Q.3710Q.3899 Resource control protocols Q.3710Q.3739 TESTING SPECIFICATIONS Q.3900Q.4099 For fu
6、rther details, please refer to the list of ITU-T Recommendations. Rec. ITU-T Q.3713 (03/2017) i Recommendation ITU-T Q.3713 Signalling requirements for broadband network gateway pool Summary Recommendation ITU-T Q.3713 describes the scenarios, architecture and signalling for broadband network gatewa
7、y (BNG) pool in order to achieve the following outstanding benefits: high reliability for broadband access services, resource sharing and load balancing among multiple BNG devices which composed a pool, simplified operation administration and maintenance (OAM) and reduction of operational expenditur
8、e (OPEX) and capital expenditure (CAPEX). History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T Q.3713 2017-03-29 11 11.1002/1000/13247 Keywords Broadband network gateway, BNG, pool. * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your we
9、b browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/ 11830-en. ii Rec. ITU-T Q.3713 (03/2017) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communi
10、cation 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 Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The
11、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 by the procedure laid down in WTSA Resolution 1.
12、 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 both a telecommunication administration and a re
13、cognized 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 all of these mandatory provisions are met. Th
14、e 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 RIGHTSITU draws attention to the possibility
15、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 ITU members or others outside of the Recommen
16、dation 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 this may not represent the latest information an
17、d are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2017 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.3713 (03/2017) iii Table of Contents Page
18、 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 1 4 Abbreviations and acronyms 1 5 Conventions 2 6 Introduction of BNG pool . 2 7 Architecture of the BNG pool . 3 8 Signalling requirements for the BNG pool . 3 8.1 Signalling for
19、membership management and configuration of the BNG pool . 4 8.2 Signalling for the notification of BNG status/information . 6 8.3 Signalling for fault monitoring and notification . 6 8.4 Signalling for synchronization of user session information among BNGs 6 8.5 Signalling for user traffic schedulin
20、g among BNGs 7 Annex A The scenarios related to BNG pool . 9 Appendix I The networking methods of BNG pool 11 Rec. ITU-T Q.3713 (03/2017) 1 Recommendation ITU-T Q.3713 Signalling requirements for broadband network gateway pool 1 Scope This Recommendation describes the scenarios, the architecture and
21、 the networking method for BNG pool. It specifies signalling requirements and procedures between the controller and BNG devices. Signalling between the controller and the application is outside the scope of this Recommendation. 2 References The following ITU-T Recommendations and other references co
22、ntain 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 to investigate
23、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, the status of
24、a Recommendation. ITU-T Q.3711 Recommendation ITU-T Q.3711 (2016), Signalling requirements for software-defined broadband access network. 3 Definitions 3.1 Terms defined elsewhere None. 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following
25、 abbreviations and acronyms: API Application Programming Interface BNG Broadband Network Gateway CAPEX Capital Expenditure IP Internet Protocol IPTV Internet Protocol Television MAC Media Access Control NETCONF Network Configuration Protocol OAM Operation Administration and Maintenance OLT Optical L
26、ine Terminal OPEX Operational Expenditure OTN Optical Transport Network QoS Quality of Service 2 Rec. ITU-T Q.3713 (03/2017) SBAN Software-defined Broadband Access Network SNMP Simple Network Management Protocol VLAN Virtual Local Area Network 5 Conventions In this Recommendation: The keywords “is r
27、equired to“ indicate a requirement which must be strictly followed and from which no deviation is permitted, if conformance to this Recommendation is to be claimed. The keywords “is recommended“ indicate a requirement which is recommended but which is not absolutely required. Thus, this requirement
28、need not be present to claim conformance. The keywords “can optionally“ indicate an optional requirement which is permissible, without implying any sense of being recommended. This term is not intended to imply that the vendors implementation must provide the option, and the feature can be optionall
29、y enabled by the network operator/service provider. Rather, it means the vendor may optionally provide the feature and still claim conformance with this Recommendation. 6 Introduction of BNG pool With the fast development of broadband service/network, higher requirements for BNG are needed. This inc
30、ludes addressing the following problems when deploying BNG in current carrier networks: As BNGs are usually deployed individually, according to its geographical region, there is usually no redundancy/protection function deployed among multiple BNG devices. As a result, the high reliability requireme
31、nt for high value services, e.g., Internet protocol television (IPTV), customer leased-line services cannot be met. Given its low reliability, BNGs are not allowed to serve a large number of users simultaneously so as to avoid interrupting users service. This leads to excessive waste of BNG resource
32、s. Resource utilization in BNGs is significantly different depending on its deployment location, carried services, etc., which may also lead to the waste of BNG resources. The individual deployment of BNG increases the complexity of BNG OAM. Given the high requirements regarding the BNG deployment e
33、nvironment (e.g., the power supply, transmission resources), the individual deployment of BNGs would increase the CAPEX. A BNG pool architecture is proposed to solve the problems described above. In this architecture, BNG devices will be deployed in a moderately centralized manner. A BNG pool is com
34、posed of multiple BNG devices located in a central office or multiple central offices which are geographically adjacent to each other. Using BNG pool architecture has the following advantages: The BNG devices in one pool can provide the backup protection for each other, which can achieve the high re
35、liability to meet the requirements of high value services. The BNG devices in one pool can provide resource sharing and load balancing, which can improve the overall resource utilization. The BNG pool can be maintained and operated as a whole, which can simplify the OAM. Moderately centralized deplo
36、yment of BNG devices can reduce the demand for central office, which can greatly reduce the CAPEX. Rec. ITU-T Q.3713 (03/2017) 3 Note that the hot-standby technology has been deployed to ensure the reliability of BNG. However, this technology is based on a totally distributed approach, which makes i
37、t complicated to configure, monitor, manage and coordinate the BNG devices. This will place high pressure on the BNG control plane. The BNG pool architecture is based on a centralized control mode, which facilitates centralized/unified coordination and scheduling, and helps achieve load balancing am
38、ong the BNG devices. Under the control of a centralized controller, the pressure on control plane of the BNG can be alleviated, unified OAM for BNG devices can be achieved and differentiated requirements from the applications can be satisfied through open application programming interfaces (APIs). 7
39、 Architecture of the BNG pool Figure 7-1 The architecture of the BNG pool The architecture of the BNG pool, which is required to be kept aligned with the software-defined broadband access network (SBAN) model defined in ITU-T Q.3711, is divided into three layers, as shown in Figure 7-1. The BNG is r
40、esponsible for the packet forwarding, policy enforcing and route processing, etc. The controller performs central control and coordination among multiple BNG devices which belong to the same BNG pool. Services can be easily configured based on the application modules with the northbound APIs provide
41、d by the controller. The controller is in charge of the BNG pool, and the BNG devices forward data packets, provide the backup protection for each other and realize the load balancing among members of the BNG pool based on the actions/commands from the controller. The application interface defined b
42、y the controller is open for the upper application developers, which can satisfy the application requirements, for example, providing differentiated quality of service (QoS) for specific services/users. The detailed signalling between the application and the controller is not included in this Recomm
43、endation. The signalling between the controller and the BNG is described in clause 8. 8 Signalling requirements for the BNG pool As the hub node, the controller establishes the star-like control connections with each member of the BNG pool. To realize the high reliability and load balancing in the B
44、NG pool, the following signalling requirements between the controller and the member of the BNG pool is recommended to be specified. No new protocol is specified here, and the signalling can be implemented with existing protocols with possible extension. 4 Rec. ITU-T Q.3713 (03/2017) 8.1 Signalling
45、for membership management and configuration of the BNG pool The controller is in charge of the membership management for the BNG pool. The membership management functions include adding a new member, deleting an old member, and monitoring the status of each member of the BNG pool. Figure 8-1 illustr
46、ates the signalling flow of the membership management and configuration between the controller and the BNG device. Figure 8-1 The membership management and configuration procedure At the initial phase, the controller creates a BNG pool after receiving an external request. The request could be issued
47、 from the operator, or one application module, etc. The detailed signalling between the controller and the application is not included in this Recommendation. For membership management, the controller sets up a membership relation by adding a BNG device into the BNG pool. The message of adding a BNG
48、 pool member is generated and sent to the BNG device by the controller. A pool ID is carried in this message to identify the BNG pool. With receipt of the message, the BNG gets the information of membership and enables the corresponding BNG pool functions. The BNG device is recommended to notify its
49、 status to the controller used for the functions of the load balancing, the fault protection, etc. This notification is recommended to be periodically sent, and the controller knows the status of all members in the BNG pool. The procedure of removing members from the BNG pool is similar to the procedure of adding members. The controller is also in charge of the management of the IP address pool in the BNG pool. This IP address pool is located in the BNG, and used for allocating IP addresses to the dial-up users.
