prevent loop in the network

To prevent a loop in your network, you can utilize the Spanning Tree Protocol (STP) or Rapid Spanning Tree Protocol (RSTP). Both protocols are designed to select the fastest network path if there are redundant links in the network and prevent loops from occurring. They operate by electing a root bridge, which acts as the central hub for the network, and then establishing a tree structure to ensure that there is only one active path between any two devices.In your specific scenario, it appears that your network consists of two core switches, two distribution switches, and four access switches. The core switches are connected to each other, and the distribution switches are also connected to each other. Core01 is connected to Distribution01, while Core02 is connected to Distribution02. The issue arises when you connect Core02 to Distribution02, causing the whole network to go down.To resolve this, you can follow these steps:

1. Enable STP or RSTP on all switches in your network. This will ensure that the protocol is responsible for managing the network paths and preventing loops.
2. Configure the switches to form a loop-free topology. Make sure that there is only one active path between any two devices in the network.
3. Use the Spanning Tree Protocol to dynamically adjust the network paths when needed. This will help maintain a loop-free network and ensure efficient communication between devices.
4. Regularly monitor and maintain the network to ensure that there are no unexpected changes that could lead to a loop.

By implementing these measures, you can significantly reduce the likelihood of encountering a loop in your network and ensure smooth operation of your devices.