Network Protocols and Communications

Data communication are the exchange of data between two nodes via some form of link (transmission medium) such as cable. Now these Data are exchanged in three ways :

1. Simplex
2. Half Duplex
3. Full Duplex

Now let us understand them one by one :

• Simplex :
  Communication is always unidirectional, i.e., one device will transmit and other will receive. E.g., Keyboard, traditional monitors, etc.
• Half Duplex :
  Communication is in both directions but not at the same time, i.e, if one device is sending, the other will receive and vice-versa. E.g., Walkie-Talkies.
• Full Duplex :
  Communication is in both directions simultaneously, i.e, device can send and receive data at the same time. E.g., telephone Line.

What are Network Protocols ?
Network protocols are sets of established rules that dictate how to format, transmit and receive data so computer network devices — from servers and routers to endpoints – can communicate regardless of the differences in their underlying infrastructures, designs or standards.

Why do we need Network Protocols ?
We need Network Protocols for :

1. Message encoding
2. Message formatting and encapsulation
3. Message timing
4. Message size
5. Message delivery options

Types of Computer Networks :

Client-Server	Peer-to-Peer(P2P)
The server control over the security of the network.	No central control over security.
The server manages the network.	No central control over the network.
Clients are dependent on the server.	Clients are not dependent on the central server.
The server can be upgraded to be made more powerful to cope with high command.	If machines on the network are slow they will slow down other machines.
Data is all backed up on the main server.	Each computer is to be backed u. Data can easily be deleted by users.