Interface Rate Limiting UDP gets high! Priority with or without BWM

Hi @PeterUK,

Thank you for reaching out to the Zyxel Community regarding your USG FLEX H Series device. I understand you're experiencing unexpected behavior with Interface Rate Limiting and Bandwidth Management (BWM) when handling UDP traffic, specifically with YouTube video streaming not buffering as expected when combined with a download.

Here are some steps to review your BWM configuration and ensure it's functioning as intended:

• Verify BWM Rule Application:

  • Ensure that BWM is globally enabled on your USG FLEX H Series device.
  • Confirm that the BWM rules you've created (TCP_test and UDP_test) are active and correctly ordered. Rules are processed from top to bottom, and the first matching rule is applied.
  • Double-check that the Incoming Interface (ge5) and Outgoing Interface (WAN2) specified in your BWM rules accurately reflect your network topology and the traffic path you intend to manage.
  • For the "BWM Download/Upload/Pri" column, ensure that the priority values (6 for TCP, 7 for UDP) are correctly entered and that these priorities are within the valid range for your device. A lower number generally indicates higher priority.

• Understand BWM Limitations:

  • Bandwidth Management on the USG FLEX H Series supports shared criteria, meaning the total bandwidth limit is distributed among all clients matching the policy. For more granular control, such as per-client bandwidth management, you would need to create individual objects and apply separate policies.
  • If ge5 is part of a Bridge Interface (e.g., BR0), individual interfaces within the bridge cannot be directly selected for BWM rules; only the overall bridge interface can be configured for BWM.

• Review Session Control Settings:

  • Check your Session Control settings under Security Policy > Session Control. The default session limit is 2000 sessions per client, which includes both TCP and UDP sessions. While unlikely to be the primary cause of your specific issue, a very high number of sessions from the download manager might indirectly affect how traffic is prioritized or managed if session resources are being exhausted.

To help us investigate this further, please provide the following information:

• Network Topology Map: A diagram illustrating how your devices (including the USG FLEX H, the client performing the tests, and the internet connection) are connected.
• Firmware Version: Please confirm the exact firmware version of your USG FLEX H Series device. You mentioned V1.37 in your post, but confirming the full version number can be helpful.
• Packet Capture: If possible, a packet capture taken on the USG FLEX H's WAN2 interface while you are performing the YouTube and download test. This can help us analyze how the traffic is being categorized and prioritized by the device.
• Configuration File: If you are comfortable sharing it, an anonymized configuration file of your USG FLEX H Series device could allow us to review all relevant settings.