CAP (Wireless) suspected MTU issue?

RouterOS Wireless Networking
1

Hi Team

I'm observing this weird issue:

RouterOS 7.23

CapsMan Manager Wireless (not WiFi CapsMan) on CCR1009 'Traffic via CapsMan' connected via Ethernet (MTU1500) to the internet.

Wireless (Not WiFi) CAP on 5HacT2HnT connected via USB 55x SnapDragon Mobile CDC Dongle, MTU 1500

CAP does connect with CapsMan, no issue but traffic is sluggish - TCP connections often get stuck after connecting. Especially WinBox does connect but then times out.

Strangely I could not detect any clear MTU issue, 1472 large packets (ethernet size 1500) get through.

Same CAP, but connected via Mobile USB Dongle, but with additional WireGuard VPN to the CCR1009 => Issue also present.

Lowering MTU of lte interface to 1000 => Issue also present.

Same CAP, but connected via Ethernet instead of Mobile USB Dongle => Issue disappears.

I attempted to find any MTU settings for the CAP connection but found none.

How is the CAP <=> CapsMan max MTU being determined? What else could the issue be?

-Benoît-

2

The CAPsMAN tunnel, in principle, doesn't suffer from MTU issues, packets get fragmented if needed.

Can you test the WiFi connection using a different, known to work well, WiFi station?

3

Yes, this is what I did the whole morning. I was mistaking regarding it works via ethernet port. I don't get CapsMan Forwarding via L3 working on any 'transport'. Not via Etnernet directly, not via WireGuard. Opened a new thread.

Over a L2 connection - either directly connected via L2 or even via VXLAN, no issue.