 City, and Boston to Chicago. Undersea cables that span oceans are another example of long-haul net- works. They carry intercontinental traffic thousands of miles and connect the United States with Europe and Asia with Europe. Regional core networks connect cities that range from 200 to 400 miles apart. This includes Boston to New York City, and New York City to Wash- ington DC. Middle-mile networks These are networks that link MANs within cities to core (backbone) networks. They consist of the fiber or wireless links from a carrier's main switch within cities and rural areas to the intercity network and the Internet. Carrier Networks Metropolitan Area Networks (MANs) These links carry traffic within large cities to headend switches or routers where traffic is aggregated and connected to core networks. MANs provide an on-ramp to core networks. These networks run from a carrier's equipment in towns to Points of Pres- ence (POPs) and wiring centers. A wiring center is a location with a local telephone company switch and connections and electronics for outside cabling. A POP is the location where a switch hands off traffic to long-haul providers, and vice versa. Traffic is also often handed off to the Internet from gear within the same building. Access networks These are also referred to as first-mile or last-mile net- works. These are the networks that link a customer's premises to its provid- er's switch. Because there are SO many cable runs to individual residences, these are often the last networks to be upgraded. Access networks also include connections from major skyscrapers and office parks to a carrier's equipment. For the most part, local telephone companies and cable compa- nies own access network cabling and electronics. However, they also provide network access to other providers that sell services to customers located in another cable TV or local telephone company's network. LONG-HAUL NETWORKS: THE CORE The core, largely based on IP while still carrying older non-Voice over Internet Pro- tocol (VoIP) vo