Communication Protocols

Protocols give a set of rules to govern Data Communication.

These notes are from Protocols are the abstract objects that make up the layers of a network system.

Each protocol defines two different interfaces:

  1. service interface to the other objects on the same computer that want to use its communication services. This service interface defines the operations that local objects can perform on the protocol. For example, a request/reply protocol would support operations by which an application can send and receive messages. An implementation of the HTTP protocol could support an operation to fetch a page of hypertext from a remote server. An application such as a web browser would invoke such an operation whenever the browser needs to obtain a new page (e.g., when the user clicks on a link in the currently displayed page).
  2. a Peer interface to its counterpart (peer) on another machine. This second interface defines the form and meaning of messages exchanged between protocol peers to implement the communication service. This would determine the way in which a request/reply protocol on one machine communicates with its peer on another machine. In the case of HTTP, for example, the protocol specification defines in detail how a GET command is formatted, what arguments can be used with the command, and how a web server should respond when it receives such a command.

Elements of A Protocol

  1. Message Encoding
  2. Message formatting and encapsulation
  3. Message Timing
  4. Message Size
  5. Message Delivery Options (unicast, multicast, broadcast)


The main difference between 5G and LTE is that 5G is the technology that came after 4G LTE to increase the speed.

5G has a radio frequency of 30 to 300 GHz.

LTE, which is based on 4G technology, has a radio frequency of up to 6 GHz.

Wifi -> 2.4 GHZ and 5 GHZ Higher frequency = more data that can be transferred

Wireless networks

The first professional wireless network was developed under the brand ALOHAnet in 1969 at the University of Hawaii and became operational in June 1971. The first commercial wireless network was the WaveLAN product family, developed by NCR in 1986.

1973 – Ethernet 802.3 1991 – 2G cell phone network June 1997 – 802.11 “Wi-Fi” protocol first release 1999 – 803.11 VoIP integration