PDF of this tutorialInternet access has different meanings to different people. In this section, the concept of access will be explained for consistency within this tutorial.
Figure 1 delineates three major entities in the provision of Internet service:
- end users who want to have Internet service as well as other services, such as telephony or cable TV
- data service providers who want to supply Internet access, content services (like AOL), or other data services, such as virtual private networking
- telephony, wireless, and cable service providers who want to provide connectivity between end users and data-service providers
Figure 1. Network Model
Note that, at times, the last two entities are combined. For example, several companies such as MCI, AT&T, or Pacific Bell provide both telephony and Internet access.
Now to the question: "What is access?" To the telephony, wireless, or cable service provider, access is the network connection from the end user's home or business to the outside-plant termination point within the service node. In traditional telephony architecture, this is most commonly thought of as the twisted-pair, cross-connect point and is referred to as the main distribution frame (MDF). The remainder of the telephony's provider's network would be referred to as the switching and transport network.
In contradistinction, an Internet service provider (ISP) views access as the connection from its customer to its network. Here, access is the connection from the end-user's home or business to the gateway-access node belonging to the ISP. Thus to the ISP, the telephony's access, switching, and transport network is all part of access.
Within this tutorial, the telephony, wireless, and cable service provider's view of access is the focus of our discussion of new and emerging technologies.
