Construction And Testing Of A Distant-learning Environment Based On IP Networks

Distant-learning breaks through the limits of time and space, and reduce the education costs. That we develop modern distant-learning greatly will accelerate the education dissemination of our country and is also instructive for setting up whole-life study system. This paper is part of DLTS-23 (Distance Learning Technology Standard)—evaluation of education environment. Here we fully study iSCSI protocol design principles, construct the distant-learning environment with iSCSI as storage component, and analyze its performance. We also design and implement a tool for analyzing and testing IP networks in which distant-learning education exits with iSCSI as storage component.This paper carries out research on iSCSI protocol that is widely used in distant-learning environment now. Not only are the protocol design principles analyzed, but we compare iSCSI and other network storage solutions. The latter includes (1) the advantages of iSCSI over storage area network based on Fibre Channel; (2) performance compares of iSCSI and Network attached system (based on SMB protocol and NFS protocol), from which we conclude iSCSI performances better than NAS under the same system configuration; (3) protocol design compares of iSCSI, FC and InfiniBand under storage area network environment, from which we conclude FC and InfiniBand is more suitable for this environment than iSCSI. These compares and conclusions are very useful for choosing suitable distant-learning environment. The paper constructs iSCSI initiator and targets under RedHat7.2 (kernel version 2.4.7-10) and implements a miniport driver for iSCSI initiator driver under Windows2000. We carried out study on the parameters that affects iSCSI performance from three aspects: (1) The iSCSI parameters negotiated at the establishment of a session; (2) the hardware used in the iSCSI system (initiator and target); (3) the system parameters including the network and file system parameters. The paper analyzed the metadata traffic during metadata access and concluded that network environment may be blocked when metadata accesses happen suddenly and in large scales. Finally the paper designs and realizes a tool for testing distant-learning network environment. It can be used in IP networks in which iSCSI storage exits. By using this tool we test the object parameters of IP networks. We forward the problem of this tool and give the possible correction. This tool gives us a solution to test the network component in distant-learning environment.