新技术作业(all)新技术作业(all).docVIP

Chapter 1 1. Give the full names of the following acronyms: LAN ,WAN , MAN A: LAN--- Local Area Network; MAN----Metropolitan Area Network WAN----Wide Area Network; 2. What types are networks classified into on behalf of applications/ coverage area// transmission media/switching mode A: In term of applications, networks can be classified into three types: for voice, video and data; In term of area coverage, networks can be classified into LAN, MAN and WAN; By transmission medium, networks can be classified into two types: wired and wireless networks. By switching mode, networks can be classified into circuit switching networks and packet switching networks. 3. Think about the advantages and disadvangtages of wired transmission by comparing with wireless. A: For wired networks, the advantages are : Broadband, easy to configure, fast, long-distance; Disadvantages: less mobility; But wirless networks feature in their mobility but with disadvantages of less bandwidth, limit transmission distance, and also with less security. Chapter 2 What are the layers of the OSI model? The 7-layer OSI reference Module is as follows Application/presentation/Session/transportation/network/data link/physical Which layer determines path selection in an Internet ? A: Network layer What types of things are defined at the physical layer? A: The physical layer define procedures for physical connection and execution, it includes types of functions : Electrical: voltage level, timing and coding of voltage level mechanical : physical connecting and cabling Functional: bit-rate, max.transmission distance Which includes more overhead, connection-oriented or connectionless services? A: connection-oriented Give a brief description about the two types of VC. A: There are two kinds of virtual connections : perminant virtual connection(PVC) and switched virtual connetion(SVC) (1) PVC: a permanent virtual circuit established fo