Gain expert knowledge of the physical layer of the OSI model. Learn about different wireless technologies, including infrared and radio. Use the circuit and packet switched transmission facilities. Discover how to use modems and dial-up technologies in your WAN. Manage and fine-tune your network's performance. Secure the data on your network. Build fault-tolerant systems using redundant arrays of inexpensive disks-RAID. Learn about the different types of remote access for NT networks. Prevent and troubleshoot problems with your network. Discover how intranets, extranets, and VPNs differ, and when their deployment makes sense.