 frame, and IP networks, it's in the packet headers and distributed across configura- tion parameters in switching machines swooned over and lovingly called routers-except frame relay, which is typically a meshed, point- to-point arrangement and therefore has limited connection capability. SIGNALING There are two key parts to the signaling process: an identification scheme and a linking or connection process. Signaling can be initiated by the user or by the network. Signaling can also take place between two or more users using the network. Routing and switching depend on signaling within the framework of voice, data, and Internet. All of the switching and transmission in the world wouldn't be worth much without signaling capability. Signaling has many forms and capabilities, but only one function, which is to enable the user and the network to communicate with each other. The user tells the network what to do. The network tells the user that it has done it or failed to do it. The simple model has been around since dial telephones replaced human operators. Successful signaling and network oper- ation requires a unique terminal or telephone numbering and identi- fication plan whereby each unit or telephone is the only unit on the network with that number (Table 4-4). The equivalent in a local area network (LAN) is the media access control (MAC) address. In the Internet, it's the IP address. In North America, the telephone numbering scheme relies on a fixed, 10-digit numbering plan. Outside North America, the number of 4 NETWORK TECHNOLOGY AND METHODOLOGY digits in the plan will vary from country to country or administration. Each administration or country relies on a country code. These numbering plans were conceived and are maintained according to ITU recommendations. So the telephone number plan, or identifica- tion scheme, is service provider-based. In the world of the LAN, however, the identification of each com- puter or host is manufacturer-based. Each network interface card (NIC) is given a unique 48-byte id