Computer networks are systems of interconnected devices that allow for the sharing of information and resources. They can range from small local networks to vast global networks like the internet. Here are some key characteristics of computer networks:

1. Security: Security is crucial for protecting data and resources from unauthorized access, hacking, viruses, and data breaches. Measures such as firewalls, encryption, and user authentication are essential to safeguard network resources¹.

2. Reliability: Networks must be reliable to ensure that data and resources are always available when needed. Redundancy and backup systems help maintain network operations even in the event of failures¹.

3. Scalability: A scalable network can grow and handle more users or devices without losing performance. This is essential for accommodating growth and changing needs¹.