Book excerpt: With the rapidly increasing penetration of laptop computers and mobile phones, which are primarily used by mobile users to access Internet s- vices like e-mail and World Wide Web (WWW) access, support of Internet services in a mobile environment is an emerging requirement. Wireless n- works have been used for communication among fully distributed users in a multimedia environment that has the needs to provide real-time bursty traffic (such as voice or video) and data traffic with excellent reliability and service quality. To satisfy the huge wireless multimedia service demand and improve the system performance, efficient channel access methods and analytical methods must be provided. In this way very accurate models, that faithfully reproduce the stochastic behavior of multimedia wireless communication and computer networks, can be constructed. Most of these system models are discrete-time queueing systems. Queueing networks and Markov chains are commonly used for the p- formance and reliability evaluation of computer, communication, and m- ufacturing systems. Although there are quite a few books on the individual topics of queueing networks and Markov chains, we have found none that covers the topics of discrete-time and continuous-time multichannel mul- traffic queueing networks. On the other hand, the design and development of multichannel mul- hop network systems and interconnected network systems or integrated n- works of multimedia traffic require not only such average performance m- sures as the throughput or packet delay but also higher moments of traffic departures and transmission delay.