Packet Switching

• One router to another, full speed
• Store-and-forward (packet must be complete before sent)

What about Circuit Switching?

• No sharing
• Guaranteed performance
• But when idle no performance
• Can use frequency or time sharing

Packet switching is more efficient than circuit.

In short, it allows more users in the network at a time.

If we take the example of a 1 Mbps link with each user using 100 Kbps 10% of the time,

Circuit switching would only allow 10 users at 100 Kbps each

Packet switching would allow 35 users at > 10 users at < 0.04%.

Enables on demand network sharing, no waste.

Internet Service Model

“Internet best effort”

• Only promise is to deliver packets

Protocols

• Control sending and receiving messages
• Standardize with RFC and IETF
• How do we organize all these profiles?
• Use layerings (see OSI model)
• Uses ideal of abstraction