Packet Switching vs. Circuit Switching

Circuit Switching

• Dedicated circuit
  • Manually connect two circuits together
• Guaranteed bandwidth
  • Circuit is guaranteed 100% available for whatever you want to do
  • Maintained permanently, the actual electronic path
• Circuit maintained permanently
• Service-Level Agreement (SLA)
  • A guarantee from a company that says that they are going to deliver that kind of performance of service.
• Plain Old Telephone Service (POTS)
  • Only uses two pins (send and receive)
• ISDN
  • This is a digital subscriber line, compared to the analogue (manual) subscriber line.
  • Analogue to digital conversion
  • We can apply some integrity checks, if not we can correct it
  • Gave more speeds.
• T1, T3, E1, E3
  • These were the styles of circuits used.
  • Would be your dedicated circuit between two offices
  • Not as practical as Packet Switching.

Packet Switching

• Shared infrastructure
  • You won't actually never reach your maximum level of speed.
  • Have a big powerful infrastructure but just use a portion of it.
• Use what's available
  • Varies based on what other customers are doing
• Multipathing
  • Passing traffic over different paths.
  • You can put different applications over different paths.
• Traffic engineering
  • The process of you working with your service provider to wander what is of importance for you
  • Gives us the ability to look at the different flows and send them over different paths.
• Quick provisioning time
  • Circuit switching could take like 8 weeks.
• Low cost
  • We can't efficiently use everything that we have all the time
  • It benefits everyone
• High bandwith
• No SLA
  • Outages could exist for a couple days
  • You can purchase two broadband connections much cheaper.