Network and Network Criteria

Network

A network is a set of devices (nodes) connected by communication links. A node can be a computer, printer, or any other device capable of sending or receiving data generated by other nodes on the network.

Fig: Network

Network criteria

A network must be able to meet a certain number of criteria.

Performance

Performance can be measured in many ways, including transit time and response time. 

• Transit time: The amount of time required for a message to travel from one device to another.
• Response time: The elapsed time between an inquiry and a response.
• Performance factor
1. Number of users
2. Transmission medium
3. Capabilities of connected hardware
4. Efficiency of the software
• Performance evaluated by two networking metrics: throughput and delay. We often need more throughput and less delay.

Reliability 

Reliability measured by

• The frequency of failure
• The time it takes a link to recover from a failure
• The network’s robustness in a catastrophe

Security

Network security issues include protecting data from

• Unauthorized access 
• Damage and development 
• Implementing policies and procedure for recovery from breaches and data losses.