Dịch vụ mạng thế hệ kế tiếp P5

Packet Switched Technologies In the same way we started with the transmission infrastructure for circuit switched technologies, packet switching has a similar underlying infrastructure. At this stage, it is worth reviewing the International Standards Organisation’s Open Systems Interconnect model (ISO-OSI) that was used in Chapter 1 as a framework for the telephony signalling protocols (Figure 5.1). In the case of packet-based networks such as the Internet, since this is the one of specific interest to us, the bottom two layers of the OSI stack are populated with technologies that differ based on their geographic boundary: local area, campus or metropolitan area...