Public and Private Networks
Public Networks
- Local Exchange (LECs) such as RBOCs created in 1984.
- Interexchange Carriers (IXCs) such as AT&T, MCI, and Sprint.
- Value Added Carriers (VACs) such as America Online and Compuserve. VACs handles management and maintenance of WAN services and does some protocol service.
Private Networks
- manages its own switching equipment. Usually large organizations.