The central device in a star network topology is a server.

Star Network Topology:
A star network topology is a type of network configuration where all the devices in the network are connected to a central device called a hub or switch. Each device in the network communicates with the central device, which then relays the information to the appropriate destination device. This type of topology is commonly used in local area networks (LANs) due to its simplicity and scalability.

Central Device:
The central device in a star network topology plays a crucial role in the network. It acts as a central point of communication and manages the flow of data between all the connected devices. There are various types of central devices that can be used in a star network, such as a hub, switch, or router. However, the most common and appropriate central device for a star network is a server.

Role of a Server:
A server is a powerful computer or device that provides services, resources, and data to other devices in the network. In a star network topology, the server acts as the central point for all communication and coordination. It is responsible for managing network resources, storing and sharing files, providing authentication and access control, and hosting applications or services.

Functions of a Server in a Star Network Topology:
1. Data Storage and File Sharing: The server acts as a centralized storage location for files and data. It allows users to store and share files, ensuring easy access and collaboration.
2. Network Administration: The server provides network administration functions such as user authentication, access control, and network security. It manages user accounts, permissions, and network policies.
3. Resource Management: The server manages network resources such as printers, scanners, and other shared devices. It ensures efficient allocation and utilization of resources across the network.
4. Application Hosting: In many cases, the server hosts applications or services that can be accessed by other devices in the network. This allows for centralized control and maintenance of applications.
5. Data Backup and Recovery: The server may also perform regular data backup and recovery tasks to protect against data loss or system failures.

Conclusion:
In a star network topology, the central device, which is typically a server, acts as the hub of communication and coordination. It provides various services and resources to other devices in the network, ensuring efficient and secure data transfer. The server plays a crucial role in managing network resources, storing and sharing files, providing authentication, and hosting applications or services.