Analysis and Design of Instant Message System Based on P2P

Analysis and Design of Instant Message System Based on P2P Shen Zhiwei Ma Shaowu China Netcom Group Labs Beijing 100032 Abstract By analyzing current development conditions of mainstream Instant Message technologies and services, some detailed discussion about technical solution and formal operation deployment strategies of P2P Instant Message Services based on Internet is made. Several crucial problems of P2P Instant Message System about services management, interconnection with other instant message, security and profit-making mode are analyzed,, and how to develop P2P IM Services is proposed. Keywords P2P; Instant Message; Session Initiation Protocol; Profit-making Mode 1 Introduction At present, the application of IM (Instant Message) is used very widely, it is able to realize the integrated services based on Internet such as IP voice, data, and images. At the same time, the fee with PC voice one another is almost free,in virtue of the realizing of voice PC to phone must through fixed-line operator s interconnection, the fee is cheaper though not free. The very-low-fee or even cost-free IM software heavily shunt the traditional voice services of the operators. So need analyzing and research the IM, utilizing the technologies advantage of P2P IM to optimize operators own network and services, and bring forward the suited P2P IM scheme for operators faction. For the operators, the use of IM technologies based on P2P architecture would reduce communication equipment investment greatly, improve the network utilization rate and reduce the service development cost. And the operators could exploit many new value-added services based on P2P IM and make it become a new profit increment point. This paper proposes a solution of the IM based on P2P from the aspects of technical realization and service deployment by analyzing current mainstream IM technologies. 2 The current development conditions of Instant Message services Resently, with the rapid incensement of the number of the Internet users, the users of the IM also increase. Based on the I-Research market expection, the IM users all over the world would increase from 490 million in 2007 to 650 million in 2010, and the scale of IM market would increase from 150 million dollars to 280 hundred million dollars in 2010. The operators at home and abroad continuously propose new services. England Telecom had put forward a new Internet service that from Yahoo IM product to a phone in March 2004.China Telecom proposed Internet CALL ME IM system that provide the text message services among PC, PHS and mobile phone and the PC to 13

P2P 和 CDN 技 术 融 合 实 现 流 媒 体 业 务 phone voice service in November 2004, and the CALL ME update edition is tested in Guangdong province at present. China Mobile developed the IM Fetion based on Mobile Network that offering the text messages and voice services between a PC and a mobile phone in November 2006.China Union proposed the Mobile Network IM UMS that offering the text messages and voice services between a PC and a mobile phone in August 2007.China Netcom also provided CNCIM based on PHS in April 2007, and would propose CA based on Soft Switch. The development procedure of china IM is shown in figure 1.Figure 1(a) focuses on the time and figure 1(b) focuses on the function [1]. between different IM systems has become a serious problem[2,3]. Table.1 Contrast analyze of mainstream IM (a) For the profit-making mode, most IM platforms still use advertisement as their main way. This advertisement mode includes traditional, initiative and personal way. At the same time, it includes Internet, wireless and fixed-line Increment Services. The corporation mode makes profit by providing IM services for enterprises. The virtual telecommunication operators collect fees form the users to a dial fixed or mobile phone by using the IM software, and make profit with the IM brand patents. (b) Figure1 The development of IM in China ((a)about time,(b)about function) The contrastive analyis of current mainstream IM software such as QQ, MSN, TOM-Skype and Fetion according to the aspects of support network, work mode and protocol etc. is shown in table 1. It could be seen from table 1 that all of the IM platforms based on conventional C/S structure have their own private protocols except TOM-Skype, which is based on P2P mode and has standard protocol. So the IM system would have a bottleneck if the number of the users increases to a certain degree. At the same time, for the protocols not being opened, the interconnection 3 The technology realization scheme of P2P IM Services and deployment strategies After analyzing the contrast of the mainstream IM architecture with P2P technical features, a technical solution of the P2P IM providing a online real-time communication service across Internet, fixed and mobile networks that realized anywhere real-time communication to the users within fixed-telephone, PHS, PC, GSM mobile phone, CDMA mobile phone, GPRS mobile phone, 3G mobile phone and wifi/wimax mobile phone is proposed. The Internet communication services include the PC to PC text messages, presence of PC to PC, PC to PC voice, PC to PC video and PC to PC file transfer; the acrossnetwork data communication services consist of PC 14 信 息 通 信 技 术

to PC text messages, presence of PC to PC and PC to PC file transfer; and the across-network multimedia communication services are the PC to PC voices and PC to PC videos. At the same time, the system also supply the increment services based on content with a series of IM applications and the interface with the other services platform or content providers, for example, many people online games and personal spaces etc. management of users, platforms, contents and charges etc. In addition, the operation management level also provides the third-party interfaces. The physics topology of system is shown in figure 3. The established super node consists of chord ring and common users node connected with its adjacent super node that composed of partially decentralized structure topology. At the beginning, a node is a common node, and after it has run for certain time, Figure 2 Logical Architecture of P2P IM The solution adopts the partially decentralized structure topology and SIP/SIMPLE protocol as its calling signal, and the logical architecture is shown in figure 2. The access level is a terminal type of support services that including PC, wifi/wimax phone, fixed phone, PHS, GSM/GPRS/WAP mobile phone, CDMA mobile phone and 3G mobile phone etc. The network level is the uniform P2P overlay network above the access level, this level uses partially decentralized structure topology and is responsible for joining a peer and leaving a peer, choosing the calling route, maintaining the network stability with the chord algorithm and DHT algorithm. The service level is the system that could support services including Internet communication, the across-network data communication, the across-network multimedia communication and the increment services. The operation management level implements the the node could be converted to a super node when the node itself inspect own have enough performance and accessibility (for example, have an IP address and be able to run stably for a long time). The platform management server and content management server mostly manage every super node. The correlate information of users is stored through a database server. The message cache server stores the off-line text messages etc of the users. This system could interconnect with the operators own operation support system and the operators own increment services platform, SP/CP increment services platform and other IM systems through all kinds of interconnection gateway. All the IM services in this paper could be shown by WAP and WEB server. Considering the network of the operator, it is suggested that try to implement this system in one province or in one district in a practical deployment at the beginning. The system of P2P IM deployed in 15

P2P 和 CDN 技 术 融 合 实 现 流 媒 体 业 务 a province or a district metropolitan-area networks in the registration stage should be checked. Between (MAN), at the same time, validating usability the the validate communication the users could negotiate mechanism of P2P and the users experience effect a shared key which used for data transmission or by trial the each service function of P2P IM. As the communication stage. The system also provides the P2P architecture continuously mature, the mechanism functions of platform management and maintenance, of control and management improved, the market content release and management, system configure needs farther expand, the accumulate rich operation and management, long-distance monitoring and faults experience step by step, the internet bandwidth diagnose etc. farther increased and mobile terminal equipment its At present, much IM software have many performance better etc, we could deploy the system differences in the service function interface, and of P2P IM in core network. In this time, the system the description of data format that caused the deployment would be very flexibility that adjust the interconnection of different IM applications has dispose of super node which could deployed in core became a serious problem. Now there are two network, a province of backbone network or MAN, solutions, one is based on gateway, and the other is and super node s join, leave, failure all couldn t affect based on multi-protocol client. In this paper, a gateway the system stability. is adopted to realize the interconnection between one IM and another. On account of the real-time character of IM application that caused the network attack spread more fast and the result also more seriously through IM. We should design a specific information security IM system structure for IM garbage messages. For the security of transmission channel, a very credible encrypted channel mechanism is needed but Figure 3 Physics system topology of P2P IM there would not be a very high computing complexity. And for the enterprises, 4 Analyzing the management, it is suggested to build their own EIM (Enterprise IM) interconnection and security of P2P IM server inside, run the specific IM services, inspect and The solution of this paper proposed is a P2P IM note the flow of IM and the operation of IM users to system which could management, controlled and ensure the security of IM services [4]. operated. Before user login the system, user should send certificate request to authenticate server and 5 Analyzing the profit-making mode of through negotiation way to authenticate. The users P2P IM could login the system only using the authentication. When the operators develop the P2P IM services After the user logins the system successfully, the could earn function fee by providing the IM user need to establish a communication or exchange transmission function. The mobile IM could adopt data with the equity peer. Only after the successfully short message and IM client mode, the short message login the system, the users can search their equity charge basically by month and the client mode by peer information. Before the users exchange data, flow. At the same time, entirely deploying Increment the certificate which awarded by authenticate server Services about Internet, wireless, fixed-line etc to 16 信 息 通 信 技 术

attain the aim that through IM drive the Increment Services increased and through Increment Services attract the IM uses rise. The operators also may combine with the IM services CP/SP to cooperate and drive the whole IM industry chain harmonious developing. Except the tradition advertisement mode, the operators could attempt new mode including initiative and personal etc. For enterprise customers, the operators can provide IM servers and IM terminals to supply the IM services. And the fee of the PC to phone voice is also collected by the gateway. 6 Conclusion IM has become one of the important Internet applications after E-mail and web. The current IM architecture mostly bases on the C/S mode. The particular technical advantages of the IM system based on P2P architecture would be shown when the users and the services increase. This paper focuses on designing a logical and network architecture of P2P IM, analyzing some crucial problems about the management, interconnection, security and profitmaking mode of the P2P IM systems, and giving some practical deployment suggestions for the systems of P2P IM. References [1] iresearch market consultation. http:// www.iresearchgroup.com.cn, 2007 [2] CHEN Gui-hai, LI Zheng-hua P2P Network: Architecture, Application and Design. Beijing: Tsinghua Press,2007 [3] YANG Tian-lu, LIU Yu-hong etc. The principle of P2P network technology and the examples of system development [M]. Beijing: Post&Telecom Press, 2007 [4] ZHANG Wen-mao, ZHANG Miao etc. Instant Messaging: the Present and the Future. Mini-Micro Systems of Computers, 2007, vol.28, no.7, pp.1162-1168. 作 者 简 历 Shen Zhiwei China Netcom Group Labs, Beijing, 100032, China Ma Shaowu China Netcom Group Labs, Beijing, 100032, China 17