VXLAN bridges to br-lan strange behaviour (slow upload speed)

Hello, I am trying to use an openwrt router as a vxlan bridge i.e.:

startup script:

  • startup script creates a namespace
  • the wan interface is moved to the namespace
  • a wireguard interface is created in the namespace then moved to PID 1 namespace
  • wireguard is configured
  • the wireguard link to the endpoint is established (static route)
  • a static VXLAN interface is created that tunnels a link into wireguard
  • this VXLAN interface is bridged to br-lan

The Openwrt router is in "dumb-ap/bridge" mode with firewall disabled and wan itnerfaces removed (i.e. now a bridge not a router, the router is on the other side of the link).

Everything works BUT I have a strange and weird problem I can't debug: Download speed is always OK/FULL. Upload speed IS NOT: the interface stalls then slowly (i.e. VERY slowly) gets to the normal interface speed.

This is what happens in TWO routers, same behaviour (ZTE 286D & Xiaomi AX3600) both quad-ARM (one armv7 and the other armv8), both latest OpenWRT from Snapshot.

To explain it better: this is the Ookla Speed Test
eolo

As you can see, Download is OK (about 100 Mb/s it's an LTE link), uploads STALLS for half a second, then slowly gets to up speed.

Things I tried without success:

Disbled/enable packet steering
Disabled Firewall
Checked sysctl.conf for network configurations
Completely removed nf-modules (nat is not needed at all).

None seemed to do anything.

This happens ONLY with Openwrt so I think there is a parameter/something that blocks/filters the link in one way (i.e. "upload"). Or maybe the br-lan configuration.

My configuration on a standard ARMv7 box with Alpine Linux works flawlessly, an x86_64 box with Alpine Linux works too (i.e. no delay, upload is full speed).

Openwrt does not.

Any clues ?

I "solved" it by not using network namespaces, and using standard uci/luci interfaces and the whole concept of NAT that OpenWRT implicitly requires.

I now understand OpenWRT is based on different assumptions than a simlpe "Linux box" and that its structure is far more complex in interface labeling/configuration than a standard "ifconfig" command. And is far less flexible than it appears.

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