In a network, the management of subnet is done by:

In a network, the management of a subnet is typically done by a network administrator or a system administrator. Here are the steps they might take:

1. Planning: The administrator first needs to understand the network requirements, including the number of needed subnets and hosts per subnet. This will help in deciding the appropriate subnet mask.

2. Subnetting: Based on the requirements, the administrator will divide the network into smaller subnets using a process called subnetting. This involves changing the subnet mask of the network.

3. Assigning IP Addresses: Each subnet will then be assigned a range of IP addresses. This range will be used to assign IP addresses to devices within the subnet.

4. Configuring Devices: The administrator will then configure network devices (like routers and switches) to recognize the new subnets. This might involve setting up routing tables, VLANs, etc.

5. Monitoring and Troubleshooting: After the subnets are set up, the administrator will need to monitor the network to ensure everything is working correctly. They might also need to troubleshoot any issues that arise.

6. Maintaining and Updating: Over time, the network requirements might change, requiring the administrator to update the subnet configuration. This could involve adding new subnets, changing the size of existing subnets, etc.