What is a point-of-presence?
A point-of-presence (POP) is a point or physical location where two or more networks or communication devices build a connection from one place to the rest of the internet. A POP primarily refers to a location, facility or access point that connects to and helps other devices establish connections to the internet.
POP also stands for the e-mail Post Office Protocol; see POP3. A POP necessarily has a unique Internet Protocol address. An internet service provider (ISP) or online service provider such as an email provider or an entertainment provider has a point-of-presence on the internet and probably many more than one. The number of POPs an ISP or online service provider has is sometimes used as a measure of its size or growth rate.
A POP may actually reside in rented space owned by the telecommunications carrier (such as Verizon) to which the ISP is connected. A POP usually includes routers, servers and switches.