Browsing by Author "Tien, CM"

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Direct web switch routing with state migration, TCP masquerade, and cookie name rewriting
(2003)
Lin, YD
;
Tsai, PT
;
Lin, PC
;
Tien, CM
;
資訊工程學系
Existing layer 4 load balancers are content-blind and often have difficulty in redirecting HTTP requests. to the appropriate server in the session manner. Layer 7 load balancers, also referred to as web switches, are content-aware and support session persistence. However, most web switches employ a bi-direction architecture, which means both request and response traffic must both pass through the load balancer. This makes a web switch become a bottleneck easily. In this paper, we present a direct routing architecture to prevent response traffic from passing through the web switch. Our solution is highly scalable in the number of back-end servers. In addition, two simple but effective mechanisms, one-packet TCP state migration and cookie name rewriting to packet filter, are presented to support persistent connection and session persistence. Through the external benchmark, we prove that our system outperforms existing solutions. The internal benchmark investigates the bottlenecks of our system and suggests the future improvement.
Evolution and evaluation of Internet content delivery
(2003)
Tien, CM
;
Lin, PC
;
Lin, YD
;
資訊工程學系
;
Department of Computer Science
Internet content delivery has evolved from centralized hosting, Web replication to the recent content delivery network (CDN). Centralized hosting has the problems of high backbone bandwidth consumption and long user-perceived latency, while Web replication leads to high investment and operational costs in deploying servers in several ISP networks. However, a content delivery network acts as a third party to deliver for various content providers into many ISPs. In this paper, we Introduce the evolution of Internet content delivery and evaluate the performance of CDN. In our evaluation, we find that CDN is more cost-effective than Web replication, saves more bandwidth consumption and distribution time than traditional distribution alternatives such as FTP, has shorter user-perceived latency than centralized hosting, and Improves delivery quality of streaming media.
Scalable transparent e-mail outsourcing services for enterprises: Design and benchmark
(2003)
Tien, CM
;
Chen, CM
;
Lin, YD
;
資訊工程學系
;
Department of Computer Science
At present, most enterprises operate their own e-mail services, where poor management often leads to loss of important messages and potential commerce opportunities. Thus, there is a trend for the enterprises to outsource their e-mail services to professional e-mail service providers. In this paper, we present an open source based enterprise e-mail hosting system. The system features transparent on-fine outsourcing, friendly centralized Web-based management, and a rich set of value-added services, such as virus checking and spam filtering, and can scale to millions of accounts and tens of thousands of enterprise domains. Through the Internal tuning and external benchmark, we eliminate possible performance bottlenecks and demonstrate the scalability of the system.
SOAP request scheduling for differentiated quality of service
(2005)
Tien, CM
;
Lee, CJ
;
Cheng, PW
;
Lin, YD
;
資訊工程學系
This paper presents a SOAP request scheduling algorithm for differentiated quality of service. The scheduling algorithm can be deployed on a Web services server or any server that processes SOAP requests. Due to the resource-intensive security processing of SOAP messages, this research implements the scheduling algorithm on a QoS security server. The security server schedules the requests forwarded from the Web services server for the security processing and then sends the valid requests back to the Web services server for executing the Web services. The design of the scheduling algorithm is derived from the traditional deficit round-robin scheduling. However, the scheduling algorithm schedules requests according to the probed CPU resource consumption of requests. In the evaluation, the scheduling algorithm reveals the service differentiation on the throughput and response time and the little scheduling overhead. The resource utilizations are measured to prove the security processing is much more resource-intensive than the Web services execution.