Using a Managed Peer-to-Peer Protocol to Deliver Files within an Organization

Transcription

1 ASIA-PACIFIC SYMPOSIUM ON QUEUEING THEORY AND NETWORK APPLICATIONS Using a Managed Peer-to-Peer Protocol to Deliver s within an Organization Chih-Chin Liang a, Chia-Hung Wang b, Hsing Luh b and Ping-Yu Hsu a a Department of Management, National Central University,Taoyuan, Taiwan b Department of Mathematical Sciences, National Chengchi University, Taipei, Taiwan Abstract Content delivery for front-line staff is difficult to handle adequately in a large-scaled organization. Existing P2P methods have been utilized for delivering contents between peers passively. However, such P2P approaches have a problem about network congestion. That is, P2P approaches are easy to cause outbound traffic of a peer congested, because of large quantity of unmanaged passive connections for content delivery. This passive method causes a peer potentially retrieves no contents form a congested peer having the needed files because of long waiting time. Existing P2P method has a solution to manage the outbound traffic through limiting the number of connections for retrieving content from other peers. However, such solution is still inefficient. allowed connections are still easy to be exhausted because of requests for retrieving files from too many peers. congestion problem is still existed. Such congested network still stops a peer from retrieving needed contents. refore, the existing P2P approach is inefficient for a large-scaled organization because a congested network is forbidden in such company. This work proposes a hybrid protocol composed with passive and active mechanisms can help a starving peer to have the needed contents. That is, through this proposed protocol, an unmanaged passive connection can change to an active method by a peer having the needed contents to reduce the consumption of its outbound traffic. This work simulates the network behavior of this proposed mechanism. Through such protocol, no starving peers receiving no needed parts can be guaranteed because of the managed network behavior. Hence, utilizing this mechanism to deliver contents could be considered by an organization Keywords: P2P, telecommunication,.content delivery I. INTRODUCTION A. Pages - Printing Area Content distribution between staff members within a large-scaled company is difficult to implement because of the complex intranet environment [1]-[3], which consists of different network segments connected by various bandwidth [4]. However, the environment may cause critical contents being lost or postponed reaching destination during transmission while utilizing improper content delivery approach [5]-[10]. Existing peer-to-peer (P2P) application, such as BitTorrent (BT), is widely utilized to transmit contents between peers but no organizations apply it as the content delivery approach [6], [7]. application is unsuitable for an organization because it consumes large network bandwidth [11]. Basically, P2P is efficient because it divides a file into numerous parts in order to transmit such parts among peers. Each part of a file can be transmitted and shared between peers through a passive retrieving method. But this method occupies the outbound traffic of a peer and then sharing no contents between the peer with congested outbound traffic and other peers. Existing P2P method has a solution to manage the outbound traffic through limiting the connections for retrieving content from other peers. However, such

2 228 ASIA-PACIFIC SYMPOSIUM ON QUEUEING THEORY AND NETWORK APPLICATIONS 2007 solution is still inadequate. allowed connections are easy to be exhausted because of requests for retrieving files from too many peers. Such congested network still stops a peer from retrieving needed contents [12]-[19]. In this work, a hybrid protocol named Managed Peer-to-Peer (MP2P), composed with passive and active mechanisms is proposed [20], [21], which can be utilized to transfer contents between peers with no network congestion. That is, through MP2P, a passive connection managed by a retriever peer can change to an active connection managed by a sender to reduce the consumption of the outbound traffic of the sender. This work also models network behavior of MP2P. Through MP2P, no starving peers having no needed parts can be guaranteed because of no network congestion. Hence, utilizing MP2P to deliver contents could be considered by an organization with sparse network resource. rest of this paper is organized as follows. In Section II the related works about content delivery are illustrated. In Section III, the MP2P mechanism is described. In Section IV, the simulation result is presented. In Section V, the experiment results are discussed. Finally, conclusions are drawn in Section VI. II. RELATED WORKS A. Active Content Delivery An active content delivery method indicates a sender actively sends items to receivers. That is a push-based method [6], [7]. To adopt such method to transmit content on the network, the consumption of outbound bandwidth of a sender is managed by itself. However, in such method, a sender manages no packets that have already been sent [6], [7]. Thus, an active content delivery method must be fault-tolerant that ensures a packet is transmitted [20], [21]. To improve the accuracy of delivered contents, two mechanisms are typically employed, namely: adding information to the contents being sent to verify their accuracy and status, and utilizing the signal, and an acknowledgement, to let senders and receivers decide the next action [20]. B. Passive Content Delivery passive content delivery method indicates that the receiver sends requests to a sender for retrieving an item, and then the needed item is retrieved by the receiver actively. That is a pull-based method [6], [7]. To adopt a passive method to transmit content on the network, the outbound bandwidth of a sender is managed by receivers. correctness of the retrieved content is verified by checking the file size after the process of file transmission is completed. receiver retrieves the content again whenever the file size is incorrect [20]. However, the passive content delivery approach has a defect that exhausting the outbound network bandwidth of a sender when numerous retrievers retrieve contents from it currently [6], [7]. C. P2P Content Delivery Method modern P2P method can speed up the transmission of a large file within peers because the file is divided into parts and each part could be transmitted independently. A file is retrieved successfully after all parts of the file are collected and merged. Such P2P content delivery method utilizes the passive approach to transfer contents through the Internet [12]-[19]. However, such P2P method has the original drawback caused by the passive method: the outbound network traffic of a sender is managed by receivers and potentially congested when quantities of receivers retrieve contents from the sender simultaneously [12]-[19]. Above P2P approach focuses on ensuring that one peer can receive a completed content. However, the content delivery within an organization must consume network resource as precisely as possible. Existing solution for limiting the network congestion is simply control the allowed connection number of the file provider. However, such solution is still inadequate. A congested network within limited connection number still stops a peer from retrieving needed contents. Hence, this work adopts an active method to solve such problem because the outbound traffic can be managed by the sender, but previous studies discuss few about changing such passive method to active method [12]-[19].

3 ASIA-PACIFIC SYMPOSIUM ON QUEUEING THEORY AND NETWORK APPLICATIONS III. THE MP2P MECHANISM This work proposes an adjusted P2P protocol named MP2P employing both passive and active methods to deliver contents effectively. In MP2P mechanism, each peer has to share the information includes file name, sender name, file status, retrieving part, completed parts, receiver name, transmission method, file size, and transmission status (Table 1). TABLE 1 SHARED FILE STATUS Shared file name Status owning parts of the shared file of the sender Sender peer providin g files Receiver peer receiving files Retrieving part retrieving part of the shared file Completed parts completed parts of the shared file owned by the receiver Transmission Method file transferring mechanism of MP2P which has following methods: the passive mechanism, and the active mechanism Size file size of each receive d part Transmission Status situation of transferring part currently. status includes: the file is ready for retrieving, prepare for sending file, ready for receiving, and successful transmission design of MP2P is described as follows. MP2P is launched whenever one file needs to be transmitted. For example, Peer A is sender, Peer B is receiver, and I is the file needs to be transmitted. Peer A shares information described in Table I to neighboring peers after Peer A divides the file I into parts. Peer A records peer A as sender name, the owning parts of I as file status, the name of I as file name, passive mechanism as transmission method, and the file is ready for retrieving as transmission status. Because Peer A is the starting node, the owning parts of I of Peer A are completed. After receiving above information from Peer A, each neighboring peer of Peer A records itself as the receiver name, and records a divided part of I as the retrieving part, then passes these modifications back to Peer A. In this case, the passive procedure for transferring I begins after Peer B records it as the receiver name, the part 1 of I as the retrieving part, and passes these modifications back to Peer A. passive procedure is as follows. Peer B retrieves part 1 of I from Peer A. Whenever part 1of I is transferred successfully by Peer B, the retrieving part is changed to part 2 of I and recording part 1 into completed parts by Peer B then passed these modifications to neighboring peers including peer A. retrieving procedure of part 2 of I from Peer A is started by Peer B after above modifications are transferred to Peer A completely. In case Peer A is unavailable to share 1, Peer B will retrieve part 2 of I from other peers having the part. transmission status will change to successful transmission whenever I is transferred completely. In MP2P protocol, the active procedure is used whenever the outbound bandwidth is consumed heavily. That is, too many connections established by receivers to use the outbound traffic. To utilize active procedure, the usage of the outbound bandwidth can be managed by the sender because the manage of file transmission is changed from receivers to the sender active procedure is described as follows. transmission method is changed from passive method to active one, whenever Peer C needs to connect to Peer A for retrieving part 3 of I, but too many connections established by receivers using the outbound bandwidth of Peer A to be available to transfer part 3 of I through passive method. transmission method is changed to active method by Peer A. Peer A is then sending this modification to Peer C. passive procedure of the part 3 of I between Peer A and Peer C stops. Peer C is then waiting for part 3 of I sent by Peer A. Peer A delivers the needed parts to Peer C when the network is available to transfer content. Peer A changes the transmission status to prepare for sending file to Peer C. Peer C sends ready for receiving to Peer A, when Peer C is available to receive the content. Peer A is then sending part 3 of I to Peer C. In addition, in the MP2P mechanism, if Peer A is malfunctioned, one of the neighboring peers of Peer A, excepts Peer C, sends the request part to Peer C actively. Whenever the size of the received part is the same as the file size, Peer C sends successful transmission to Peer A. push-base procedure is finished.

4 230 ASIA-PACIFIC SYMPOSIUM ON QUEUEING THEORY AND NETWORK APPLICATIONS 2007 III. SIMULATION RESULTS To understand the difference, this work simulates the bandwidth consumption of a sender adopting MP2P and P2P. MP2P simulation describes as follows. This work uses ProModel as the simulation tool (Fig.1). We assign 5 peers, AAA is the sender, BBB, CCC, DDD and EEE represent the receivers. This work assigns peer AAA has one outbound connection and observes the network consumption of the connection. All peers use the only one connection to transfer packets. peer AAA sends packets to EEE through passive protocol and sends packets to the rest of peers through active one. inter arrival time assumes following exponential distribution, one packet arrives at one time. Obviously, because this simulation assumes one peer has only one connection and time is limited, arrived packets might queue at AAA. A packet deliver to BBB, CCC, DDD, or EEE depend on the packet designated to deliver through active method or passive one. transmission rate is 9 KB/seconds, the distance of each peer is the same. In addition, the P2P simulation is similar as MP2P, but all receivers use passive method to transfer packets. Figure. 1. Simulation Environment Simulating 100 hours, to compare with the delivered packets and total issued packets, the result shows the packets can be delivered is 15.2% in MP2P and 5.4% in P2P. In addition, to compare with P2P and MP2P, the average delivered packets could be up 39.6% within a fixed time slot while adopting MP2P. IV. CONCLUSIONS This work proposes a managed peer-to-peer protocol (MP2P) to send packets instead of the passive P2P approach. To eliminate defects of the unmanaged bandwidth consumption caused by P2P method using passive protocol, the MP2P method using both passive and active protocols. Finally, the simulation result shows the MP2P has outstanding performance on packets delivery. To compare with the delivered packets and total issued packets, the result shows the packets can be delivered is 15.2% in MP2P and 5.4% in P2P. In addition, to adopting MP2P, the average delivered packets could be up 39.6%.

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