11-02-2012, 04:28 PM
IP Packet Switching
[attachment=17512]
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
[attachment=17512]
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