Context: A virtual ISP (VISP) is an operation that purchases services from another ISP, sometimes called a wholesale ISP in this context, which allow the VISP's customers to access the Internet using services and infrastructure owned and operated by the wholesale ISP. VISPs resemble mobile virtual network operators and competitive local exchange carriers for voice communications.

Question: What is a VISP?
Answer: virtual ISP

Question: What do VISPs resemble? 
Answer: mobile virtual network operators

Question: What do visps purchase services from? 
Answer: a wholesale ISP

Question: Who does an ISP purchase services from?
Answer: Unanswerable

Question: Who do wholesale ISP purchased services from?
Answer: Unanswerable

Question: What do virtual network operators resemble?
Answer: Unanswerable

Question: How do VISP's customers access the Internet?
Answer: Unanswerable