A point of presence (PoP) is an artificial demarcation point or interface point between communications entities. It may include a meet-me-room.
An Internet point of presence is an access point to the Internet. It is a physical location that houses servers, routers, ATM switches and digital/analog call aggregators. It may be either part of the facilities of a telecommunications provider that the Internet service provider (ISP) rents or a location separate from the telecommunications provider. ISPs typically have multiple PoPs, sometimes numbering in the thousands. PoPs are also located at Internet exchange points and colocation centres.
Virtual point of presence
(virtual PoP) A point, via which users can connect to an Internet access provider, which is not operated by the provider. The useris charged by the telephone company for the call to the virtualpoint of presence which relays his call via some third party circuitto the Internet provider’s central location. This is in contrast to aphysical point of presence (PoP) which is operated by the Internetprovider themselves. The advantage of a virtual PoP is that theprovider can keep all their modems in one location, thus improvingavailability and maintenance, but users do not have to pay long-distance call charges to that point.