ILITIES, AND SERVICES services. One side of the equipment is connected to the network facility that provides access to network services. The other side of the equipment interfaces to local area network (LAN), private branch exchange (PBX), and Moving Picture Experts Group (MPEG) com- pression and decompression equipment. Figure 5-1 shows an example of the common equipment found at a typical operations site engaged in production, post-production, and on-air transmission operations. Basic service requirements include telephone or dial-up service, data transmission, Internet access, and content transport within and out- side each site. Group ownership operations may range from half a dozen operational sites to 50 or more. The geographic scope might range from purely local stations to statewide or regional or national in size. This level of detail may seem insufficient when considered from a broadcast operations point of view; however, it is quite satisfactory for network planning and design purposes where the objective is to inform a potential equipment and/or service provider. It can be used to delineate equipment from services, and it can also be used to inform potential consultants or network designers about their re- sponsibilities in terms of a design, project, or program management. Network Clock RJ 11/ 31/45 E1/T1 E3/DS3 802.xx E3/DS3 VLAN - Common OC3/STM1 Router 802.xx Network Interface Equipment SMPTE Codec 802.xx Station FIGURE 5-1 Typical Operations Site Common Network Equipment PRACTICAL IP AND TELECOM FOR BROADCAST ENGINEERING AND OPERATIONS E3/DS3 OC3/STM1 Site 2 Site 3 E3/DS3 OC3/STM1 Site 1 Site 4 FIGURE 5-2 A Four-Site Network Topology Diagram On the communications network side, the level of detail goes sub- stantially deeper in the form of definition, description and use of various network elements, and several alternatives for linking them together. Figure 5-2 is a simple sketch showing four sites with links between each. The link arrangement depicted in Figure 5-2 is only one of several possibil