what’s the Internet?
Network of networks
what’s a protocol?
Format, Order of messages and Action taken by end systems incommunication
network edge; hosts, access net, physical media
Dialup, DSL, HFC, Ethernet, WiFi
Twisted Pair, Coaxial, Optical fiber, Radio link
network core: packet/circuit switching, Internet structure
Circuit switching: dedicated resource, need reservation,resources wasted if not used. Examples: FDM, TDM
Packet switching: resources used as needed, statisticalmultiplexing (more users, allow bursty data)
Internet structure: Hierarchical