Communication hardware

Communicaiton channels

Wired

• Local area networks(LANs)

  • 1-2 kilometers long
  • 10 - 100 gigabytes per second(Gbps)
  • Communication within LAN takes around submillisecond.

• Wide area networks(WANs) :

  • Use of optic cables
  • transmit up to 171Gbps over 400 different channels, giving more than 70 terabits per second
  • little slower than speed of light as seen below
    

Question: How long will it take to make a connection between New York and Sydney?

As shown above, one way trip with the travel time for fiber optic cable takes around 80ms. However, in reality it takes longer than this as data needs to pass through routers. This is commonly referred to as last-mile delay. When connection is delivered from local ISP to the end user, following happens:

• Signal conversion
• Routing and switching
• Congestion
• Wireless transmission

Wireless

The most widely used WiFi protocol, 802.11ac, allows for maximum (theoretical) data rates of up to 5,400 Mbps.