While many applications require a certain level of network security; communication networks characterized by different service providers, transmission means and implementer solutions such as asynchronous transfer mode (ATM), internet protocol version 4 (IPv4), IPv6 and MPLS. Provides comprehensive coverage of QoS issues within heterogeneous network environment, QoS Over Heterogeneous Networks? look to find solutions to such questions suitable QoS in heterogeneous networks and what its impact on performance if information across the different networks that carry out specific QoS schemes. Information on QoS mapping in terms of service level specification (SLS) and in-depth discussion on issues related to chapter end-to-end (E2E) QoS, QoS architecture, QoS over heterogeneous networks and QoS internetworking and mapping.