Internet implications of telephone access

What good is a network if it can't be accessed? In fact, access is often a single point of failure for data or telecommunications network subscribers. In the US, the Public Switched Telephone Network is the primary provider for the vast majority of voice service users. The PSTN is also the principal source of circuit-switched access to ISPs for an increasing number of PCs. Therefore, PSTN access availability is a benchmark for those who are considering providing or acquiring Internet access or voice services. The article presents a typical Internet user connection through the local PSTN to an ISP. In the PSTN, local or central office switches serve as network access nodes. Although considerable redundancy and fault tolerance are engineered into both the network itself and these switches, total service outages do occur. In the future, terms such as local carrier and long-distance carrier are likely to disappear as more end-to-end carriers emerge, providing integrated voice and data services. User demands for carrier transparency will dictate having a highly reliable, available, and survivable network access infrastructure. To date, access networks have emphasized connection speed to alleviate end-to-end latency problems. However, as subscribers experience low latency, service providers who offer dependable access will be the survivors. Fast access that isn't reliable won't be acceptable for home e-commerce.