Summary

WAN switching methods

switching methods are the ways a network moves traffic from a source to a destination through intermediate switches/routers, including how resources on each hop are reserved or shared.

Circuit Switching

• a dedicated end-to-end path is established before data flows; capacity is reserved for you until you hang up (time slots or wavelengths are reserved)
• E.g. traditional telephone network
• circuit means channel to communicate.
• correct order of data.

How it work

• Each call circuit occupies fix time-slots using copper lines.

Packet Switching

• Data is split into packets that are forwarded node to node; each packet have it own path to the destination; Hence the order of arrival is not well-order.
• Internet’s Default model with router:
  • Routers make per-packet decisions (best-effort)
  • when you are idle, others can use the link
• Different to Circuit switching:
  • no session/ channel is established prior to data transfer.

Frame Relay

• virtual-circuit packet-switched
• give you logical circuits (PVCs) across their cloud
• we can connect across WAN and share bandwidth with other people securely,