UNIT-I 1. What are the three criteria necessary for an effective and efficient network? The most important criteria are performance, reliability and security. Performance of the network depends on number of users, type of transmission medium, and the capabilities of the connected h/w and the efficiency of the s/w. Reliability is measured by frequency of failure, the time it takes a link to recover from the failure and the network’s robustness in a catastrophe. Security issues include protecting data from unauthorized access and viruses. 2. Group the OSI layers by function? The seven layers of the OSI model belonging to three subgroups. Physical, data link and network layers are the network support layers ; they deal with the physical aspects of moving data from one device to another. Session, presentation and application layers are the user support layers ; they allow interoperability among unrelated software systems. The transport layer ensures end-to-end ...
