Here's some info on a 25C:
Job training for a Network Switching Systems Operator requires nine weeks of Basic Training, where you learn basic Soldiering skills, followed by 17 weeks of Advanced Individual Training, including hands-on training with network switches and associated equipment.
As your Network Switching Systems Operator career continues, you will have the opportunity to take more classes and receive more advanced training.
Training and classroom work will typically cover these topics:
Maintaining communication network equipment and switches
Operating and installing communication equipment
Operating diagnostic equipment specific to network switches