Here's my LAN layout:
[Laptop (Windows 10)] [Raspberry Pi (Ubuntu)]
\ /
(Layer 2 Switch)
|
(Wireless router w/ gigabit LAN)
|
(Wireless router w/ 100 Mbps LAN)
|
Internet
I'm using the Raspberry Pi as a NAS, so I want gigabit speeds between the Pi and the Windows laptop.
The setup was LAN-to-WAN between the two routers, and I had gigabit speeds between Windows and Pi.
I've just changed it so the gigabit router is in LAN-to-LAN mode (ethernet plugged into LAN port, DHCP disabled). But now, Pi and Windows only talk at 338 Mbps! What's up with that?
My understanding is that the switch will direct the traffic directly from one to the other, without involving the routers. (Also, pathping/tracert don't show any other IP addresses between the two.) However:
- When I run the iperf3, all three lights on the switch blink frantically - including the one to the router.
- The speed is gigabit when I allow the gigabit router to be its own boss (DHCP enabled, connected WAN-to-LAN).
- The speed is ~338 Mbps both when I set the gigabit router as the secondary router (DHCP off, LAN-to-LAN), and when I remove the gigabit router, connecting the switch directly to the 100 Mbps router. Same speed in both cases, so the slow router is clearly involved.
(Details: I'm measuring with iperf3. The Windows machine is using iperf3 in WSL, with an ethernet-to-USB 3.0 adapter. The switch is a D-Link DGS-105, the gigabit router is a TP-Link Archer C2, the 100 Mbps router is a Fritz!Box 7430. I've only measured with Windows as client and Pi as server; I can't get it to work the other way round, even with firewalls disabled.)
arp -a
orip neigh
) show the correct MAC addresses for the opposite host?