Banana Pi BPI-R3: Switching Performance


I've been using multiple OpenWrt compatible routers and most of them have a dedicated Switch configuration / VLAN management menu. Here's an R7800 for example:

The internal VLAN / network diagram is something like this:

Now on a Banana Pi BPI-R3 (OpenWrt Wiki) there's no such menu:

Screenshot 2024-03-10 163959

And software wise all ports seem to be connected to the CPU individually:

I looked into the router's documentation and it seems to have a MT7531AE switch chip:

My questions:

  1. When there's traffic going from LAN1 to LAN2 does it reach the CPU or is it just the switch?
  2. Assuming everything gets into the CPU, won't this perform worse than the R7800? If the CPU get's into 100% load no switching will happen? Am I right?
  3. How can I setup VLANs in this conditions? Why there isn't a Switch config menu?

Thank you.

You're going to see this newer configuration more and more frequently. The difference is an older swconfig-based configuration vs. the newer DSA configuration. Due to numerous reasons, many devices' switching functionality is being moved to DSA and so this is really the way things will be from here on out. With a DSA-based switch configuration, you will configure VLANs through the "Bridge VLAN tagging" options in the bridge interface. (Network -> Interfaces; Devices tab; Select the bridge to configure such as br-lan; select the "Bridge VLAN tagging" tab)

As for performance, the difference can vary based on configurations. Yes, the CPU is capable of seeing the traffic every bit as much as it would be under the old swconfig system. However, the switch still performs its actions within the switch, so you don't have the extra overhead or slow-down that you would face were it entirely separate devices connected to entirely separate ports on the CPU.

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Thank you for the clarification. Since you told me it was "DSA configuration" I able to find the follow pages that explain it all.

…and the next version of OpenWrt will migrate ipq806x, as in the r7800, to DSA as well.

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