In a Token Ring network, which method is used to control access to the network?

In a Token Ring network, the method used to control access to the network is token passing. This access method functions by using a special data packet known as a "token." Only the device that possesses the token is allowed to transmit data on the network. This ensures that there is a systematic and orderly way for devices to communicate, preventing data collisions that can occur in other network types where multiple devices may try to send data simultaneously.

When a device wants to send data, it must wait until it receives the token. Once it has the token, it can attach its data to the token and send it around the network. After the data has been sent, the token is released so that other devices can use it to transmit their own data. This method is effective in managing access to the network and maintaining overall performance and reliability.

In contrast, the other methods mentioned, such as contention and Carrier Sense Multiple Access (CSMA), are more prevalent in network types like Ethernet, where devices compete for access to the transmission medium. Round-robin is a scheduling method rather than an access control method for networks. Therefore, token passing is unique to Token Ring networks, facilitating structured communication and avoiding the issues of collisions and data loss.