Research on Unified Policy Control Platform of Fixed / Mobile Converged Network
1 Introduction Fixed-mobile convergence (Fixed-mobile Convergence, FMC) is the basic direction of the evolution of next-generation networks. The demand for network convergence arises from the competition of operators' access services and the willingness to reduce the cost of network operation and maintenance. It is designed to provide operators with a unified core network control and management platform, and a unified service experience for end users, without having to distinguish the access technology used to access this service. Through convergence, operators will further increase the utilization rate of assets, expand coverage, improve service ease of use, and expand network service capacity. Policy control was first proposed by the IETF in the process of enhancing the evolution of IP networks. First introduced by 3GPP to the R5 version of the UMTS system, that is, Policy Control and Charging (Policy Control and Charging, PCC) architecture, its purpose is to apply policy control to the communication network resource access and use process. The PCC architecture maps the QoS requirements of the application-level session service data flow to the QoS requirements of the IP-CAN access transport network bearer-level service to ensure data transmission, and implements the service data flow-level charging function according to the operator's charging strategy. The PCC architecture allows operators to reasonably allocate and effectively control the network's service capabilities. The tariff competition among operators makes broadband services cheaper and cheaper, and users gradually tend to use monthly subscriptions for unrestricted use of bandwidth, making ARPU values ​​continue to decline. The P2P service shifts the network bottleneck from the server to the operator's network, and the cost pressure is also transferred from the ISP to the operator. To solve this problem, fixed-line operators introduce resource admission control technology into IP networks to monitor and reasonably allocate network resources and develop new tariff strategies to facilitate the rapid deployment of new services (such as IMS) and improve user services. Experience, so that operators get rid of the dilemma of network pipeline. At present, the main research includes BBF BPCF, TISPAN RACS, ITU-T RACF and so on. Fixed networks and mobile networks are moving towards deep integration. The unified IMS architecture implements a unified core control network for fixed and mobile access. The importance of unified policy control and charging architecture in the evolution of converged networks has gradually become more prominent. At this stage, different standardization organizations have different research perspectives and progress on policy control. Incompatible architectures have become obstacles to the unified policy control and charging functions of the converged network. Based on a brief description of the progress of 3GPP's existing FMC related research and the technical points of unified IMS, this paper compares the fixed and mobile network policy control architecture and functions based on TISPAN RACS and 3GPP PCC, and then proposes a The architecture is based on a unified policy control architecture for fixed and mobile converged networks that integrate policy control related functions of other standardization organizations. The architecture supports unified policy control for mobile and fixed networks of the same operator, including fixed / mobile network collaboration platforms and fixed / Two development stages of mobile network convergence platform. 2 3GPP FMC key technology introduction The related work of 3GPP FMC is reflected in the fixed broadband access to IMS (Fixed Broadband Access to IMS, FBI) ​​in R7 and the requirements for interoperability of traditional networks. FBI studied the impact of FMC on IMS from the access level. The main work is completed by the 3GPP SA2 and CT working groups. The direct work result is TR 23.819, which has now been converted into CR to modify the IMS specifications involved, such as TS 23.228, TS 24.229, TS 29.163, etc. FBI-related work can be divided into two levels: First, support for fixed-line NGN, which requires IMS to support various fixed access methods at the same time. 3GPP and TISPAN form a joint working group to study IMS enhancements and impacts on NGN, including extended Gq interface to support NGN access, SIP header domain supplementary fixed access positioning, and IPv6 / v4 address translation with IM-ALG and TrGW And private network traversal. The second is the problem of interworking with traditional circuit domain services. In the existing IMS framework, IMS services are carried on the packet domain and are in an interworking relationship with the circuit domain. The 3GPP CT working group focused on the needs of related functions, as well as the basic architecture that supports traditional circuit domain signaling, bearer, and various supplementary services. Another important research in 3GPP's FMC category is unified IMS (Common IMS). Although IMS was first proposed by 3GPP, because IMS adopts SIP architecture, it has the advantages of access independence, support for user roaming and centralized management of user data, which makes it possible to achieve network convergence based on IMS. Unified IMS, as a unified core control network supporting fixed and mobile access, meets the overall network capability needs of different versions of IMS such as 3GPP and TISPAN R1, and can also meet the standardization organizations such as 3GPP, TISPAN, 3GPP2, etc. The latest network capability requirements in other areas have been widely recognized. The core of Common IMS is Core IMS, which includes CSCF, SLF, MRFC, MGCF, BGCF and other functional entities. It is the basic network and basic business capability architecture of IMS, which implements basic functions such as basic session control, media resource control, and interconnection. NASS is suitable for fixed network terminals to access Common IMS, which is similar to the GGSN function of mobile networks. It mainly implements fixed terminal UAAF, assigns IP to fixed terminal (NACF: similar to DHCP server), and delivers PCSCF address, application server address and other information to the terminal. RACS mainly provides admission control and gateway control functions (including public and private network IP address translation control functions). Admission control mainly includes checking the authorization of contracted data saved by the access network attachment subsystem according to the operator's specific policy rules and resources, checking the consistency of user request bandwidth, predetermined bandwidth, and used bandwidth. The access gateway control function (AGCF) interacts with network elements such as RACS and CSCF to complete the interworking of ISUP signaling and analog or ISDN signaling encapsulated in SIP. It is an important functional entity for PSTN / ISDN simulation. The network capabilities of the unified IMS include registration, authentication and authorization, centralized management of user data, service triggering, IP multimedia session control, identification, encoding and addressing, network interworking, SIP compression, and complete billing capabilities. 3 Comparison of fixed and mobile network policy control architecture and functions Research on the control mechanisms for authorization, reservation, and allocation of QoS and charging strategies for fixed and mobile networks has been conducted simultaneously in different standardization organizations. Although the research topics are the same, the architecture, interface protocol and functional details of the solution are different due to the different network objects studied. This chapter explains the difference between the PCC architecture of 3GPP and the RACS architecture of TISPAN. (1) Different ways to control the access network RACS maintains network topology and resource status through X-RACF, and implements resource admission control functions. 3GPP PCC controls IP-CAN, not the nodes in the access network. The 3GPP PCC is responsible for resource authorization, and the access network is responsible for resource admission control. (2) Different degrees of support for network access technology Although RACS has been improved in the R2 version so that it can be applied to any access type, there is no in-depth and specific research on other access technologies besides the fixed network. The 3GPP PCC architecture is independent of the access technology. It is applicable to all access technologies that conform to the 3GPP IP-CAN definition, but is mainly aimed at mobile access networks. Therefore, PCC's support for nomadic, roaming application scenarios and processes and other mobility aspects is also more complete. (3) Different requirements for terminal capabilities RACS has no strict requirements on the terminal's QoS signaling capability. The terminal required by 3GPP PCC must support QoS signaling. QoS signaling can be explicit, such as GPRS; it can also be implicit, such as WLAN. (4) Different research levels in billing strategies PCC's support for billing is relatively complete, supporting multiple billing methods such as online billing (Gy interface), offline billing, and flow billing (Gz interface). While RACSR2 only defines the Rf interface to support offline charging, research on online charging is still blank. (5) Different implementation strategies for IMS border gateway control RACS incorporates research on IMS border gateway control technology, such as the NAT / NAPT mechanism, into the BGF function. The 3GPP PCC architecture does not include this part. (6) Different support for specific business RACS has a complete solution to support multicast control of IPTV services. PCC does not support IPTV services. Support for IPTV services is considered to be a bright spot in TISPAN's long-term evolution research direction. In short, the 3GPP PCC architecture provides a mature resource control and charging strategy solution. Major industry operators use PCC as a benchmark for unified policy control platforms for fixed and mobile converged networks. The RACS solution contains more function points (such as permission control) and can support IPTV services, but in the short term there is a lack of business application requirements. Other standardization organizations (such as BBF), most of the strategic control architecture solutions given are not mature enough and need to be further improved. Commercial Coffee Urn,Coffee Urn,100 Cup Coffee Urn,Large Coffee Urn FOSHAN FORTUNE ELECTRICAL APPLIANCE CO.,LTD , https://www.coffelady.com