SSL Backend Forwarding Scheme in Cluster-Based Web Servers

State-of-the-art cluster-based data centers consisting of three tiers (Web server, application server and database server) are being used to host complex Web services such as e-commerce applications. The application server handles dynamic and sensitive Web contents that need protection from eavesdropping, tampering and forgery. Although the Secure Sockets Layer is the most popular protocol to provide a secure channel between a client and a cluster-based network server, its high overhead degrades the server performance considerably and, thus, affects the server scalability. It improving the performance of SSL-enabled network servers is critical for designing scalable and high-performance data centers. We examine the impact of SSL offering and SSL-session-aware distribution in cluster-based network servers. We propose a back-end forwarding scheme, called ssl_with_bf, that employs a low-overhead user-level communication mechanism like Virtual Interface Architecture to achieve a good load balance among server nodes. We compare three distribution models for network servers, Round Robin, ssl_with_session and ssl_with_bf, through simulation. The experimental results with 16-node and 32-node cluster configurations show that, although the session reuse of ssl_with_session is critical to improve the performance of application servers, the proposed back-end forwarding scheme can further enhance the performance due to better load balancing. The ssl_with_bf scheme can minimize the average latency by about 40 percent and improve throughput across a variety of workloads. Key wards: Web services such as e-commerce Protection from eavesdropping Tampering and forgery INTRODUTION For example, E-Biz reported about $1.9 billion loss in Overview of the System: Due to the growing popularity from the Secure Sockets Layer (SSL), which is commonly of the Internet, data centers/network servers are used for secure communication between clients and anticipated to be the bottleneck in hosting network-based Web servers. Even though SSL is the de facto standard services, even though the network bandwidth continues for transport layer security, its high overhead and poor to increase faster than the server capacity. It has scalability are two major problems in designing secure been observed that network servers contribute to large-scale network servers. Deployment of SSL can approximately 40 percent of the overall delay and this decrease a server’s capacity by up to two orders of delay is likely to grow with the increasing use of dynamic magnitude. Web contents. For Web-based applications, a poor In addition, the overhead of SSL becomes even more response time has significant financial implications [1-7]. severe in application servers. Application servers provide revenue in 1998 due to the long response time resulting Middle-East J. Sci. Res., 20 (6): 752-755, 2014 753 dynamic contents and the contents require secure ssl_with_bf models, are essential to minimize the SSL mechanisms for protection. Generating dynamic content overhead. Second, the average latency can be reduced takes about 100 to 1,000 times longer than simply by 40 percent with the proposed ssl_with_bf model reading static content. Moreover, since static content compared to the ssl_with_session model, resulting in is seldom updated, it can be easily cached. Several improved throughput. Third, the proposed scheme efficient caching algorithms have been proposed to provides high utilization and better load balance across reduce latency and increase throughput of front-end all nodes. The rest of this paper is organized as follows: Web services [5-8]. However, because dynamic content a brief overview of cluster-based network servers, useris generated during the execution of a program, caching level communication and SSL is provided. Section 3 dynamic content is not an efficient option like caching outlines three distribution models, including our proposed static content. Recently, a multitude of network services SSL back-end forwarding scheme. have been designed and evaluated using cluster platforms. Specifically, the design of distributed Web Description of the Problem servers has been a major research thrust to improve Existing System: the throughput and response time [9]. It is the first Web server model that exploits user-level communication in a In existing system, they have used to develop the cluster-based Web server. Our previous work reduces project using Round Robin [RR] model and the response time in a cluster-based Web server SSL_with_Session model. Those models are not using co scheduling schemes. In this paper, first, we effective [12]. Those models are not able to give the investigate the impact of SSL offering in cluster-based out put in time and the thorough put also lesser network servers, focusing on application servers [10], than that their expected output. which mainly provide dynamic content. Second, we These models had made the Latency problem and show the possible performance improvement when the minimal through put. For this problem they SSL-session reuse scheme is utilized in cluster based introduced the SSL_with_bf (Backend forwarding) servers. The SSL-session reuse scheme has been tested model is to overcome the existing problems. on a single Web server node and extended to a cluster We going to implement SSL_with_Backend system that consisted of three Web servers. In this paper, Forwarding model in our proposed system. we explore the SSL-session reuse scheme using 16-node and 32-node cluster systems with various levels of Proposed System: workload. Third, we propose a back-end forwarding mechanism by exploiting the low-overhead user-level In our Proposed System, We are going to implement communication to enhance the SSL-enabled network the SSL_with_Backend Forwarding model server performance. (Algorithm) is to overcome the problem of existing XYZ To this end, we compare three distribution models in clusters: Round Robin (RR), ssl_with_session and ssl_with_bf (backend_forwarding). The RR model, widely used in Web clusters, distributes requests from clients to servers using the RR scheme. ssl_with_session uses a more sophisticated distribution algorithm in which subsequent requests of the same client are forwarded to the same server, avoiding expensive SSL setup costs. The proposed ssl_with_bf uses the same distribution policy as the ssl_with_session, but includes an intelligent load balancing scheme that forwards client requests from a heavily loaded back-end node to a lightly loaded node to improve the utilization across all nodes. This policy uses the underlying user-level communication for fast communication. Extensive performance analyses with various workload and system configurations are summarized as follows: First, schemes with reusable sessions [11], deployed in the ssl_with_session and system. This model will reduce the latency and increase the throughput than the existing system (Round Robin model and SSL_with_Session). The Secure Socket Layer_with_BF model is very helpful for load balancing of the server. This will reduce the load of the server while the server is being busy. These are the advantages of our proposed system. The ssl_with_bf scheme can minimize the average latency by about 40 percent and improve throughput across a variety of workloads. Module Descriptions Authentication Module: This module is to register the new users and previously registered users can enter into our project. The admin only can enter and do the uploading files into the servers. Middle-East J. Sci. Res., 20 (6): 752-755, 2014 754 IP Address Representation Module: This module is to the different functions clearly and quickly. give the IP addresses which we are going to assign those Initially as a first step the executable form of the as servers. We can enter and view IP addresses from this application is to be created and loaded in the common module. server machine which is accessible to the entire user and Load Servers Module: This module is, the administrator is to document the entire system which provides only can enter into this module. The administrator will do components and the operating procedures of the the encryption of the text file and store into the servers system. which we are assigned in IP representation module. Implementation is the stage of the project when the This module will make the both public and private key for theoretical design is turned out into a working system. the cryptography. Thus it can be considered to be the most critical stage in Load Balancing Module: This module is, the users can confidence that the new system will work and be enter into this module and can view the file name which effective. the administrator stored into the servers. The user can The implementation stage involves careful planning, select the file from the list and can download from the investigation of the existing system and it’s constraints server which is in idle state. We will get the response time on implementation, designing of methods to achieve and from which server we are getting the file [13]. changeover and evaluation of changeover methods. Finally we can get the decrypted file from the key pair. Implementation is the process of converting a new The SSL protocol: on user training, site preparation and file conversion for Implementation: Implementation is the most crucial RR, ssl_with_session and ssl_with_bf, through stage in achieving a successful system and giving the simulation. The simulation model captures the VIA user’s confidence that the new system is workable and communication characteristics and the application effective. Implementation of a modified application to server design in sufficient detail and uses realistic replace an existing one. This type of conversation is numbers for SSL encryption overheads obtained from relatively easy to handle, provide there are no major measurements. Simulation with 16-node and 32-node changes in th