I have a XMG1915-10EP V4.80(ACGP.3)

Hi @bptrader1,

Welcome to the Zyxel Community!

Frequent "Link down, link up errors" and "STP topology changes" on your XMG1915-10EP (V4.80(ACGP.3)) often indicate a network loop or an unstable physical connection.

To troubleshoot this:

1. Check Physical Connections and Cables: Inspect all cables for damage and ensure secure connections.
2. Verify Port Configuration: Ensure ports are enabled and correctly configured. If using SFP/DAC cables, confirm the media type setting under Port > Port Setup matches the cable type.
3. STP Configuration:
   1. Enable Rapid Spanning Tree Protocol (RSTP): Go to Menu > Advanced Application > Spanning Tree Protocol > Configuration and select "Rapid Spanning Tree".
   2. Configure STP Bridge Priority: Under Menu > Advanced Application > Spanning Tree Protocol > RSTP, set the bridge priority. A common practice is to set the root bridge to 4096.
   3. Implement Loop Guard: If issues persist, consider enabling Loop Guard on specific ports to prevent loops from unidirectional link failures.

If the above does not resolve the issue, kindly provide us with more information, such as your network topology and the TechSupport Info file. This will help us better analyze and assist you with the problem.