10-06-2017, 07:07 AM
IP Packet Switching
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Simple Network: Nodes and a Link
Node: computer
End host: general-purpose computer, cell phone, PDA
Network node: switch or router
Link: physical medium connecting nodes
Twisted pair: the wire that connects to telephones
Coaxial cable: the wire that connects to TV sets
Optical fiber: high-bandwidth long-distance links
Space: propagation of radio waves, microwaves,
Links: Delay and Bandwidth
Delay
Latency for propagating data along the link
Corresponds to the length of the link
Typically measured in seconds
Bandwidth
Amount of data sent (or received) per unit time
Corresponds to the width of the link
Typically measured in bits per second
Beyond Directly-Connected Networks
Switched network
End hosts at the edge
Network nodes that switch traffic
Links between the nodes
Multiplexing
Many end hosts communicate over the network
Traffic shares access to the same links