Hello,
I'm using two TP-Link routers.
Archer C7 v5 is the main one (connected to WAN).
TL-WR841N v9 is configured as Dumb AP and located at opposite end of my apartment.
Both routers are connected with an Ethernet cable between LAN<->LAN ports.
Now I noted slow speed on a secondary router, no matter over Cable or Wi-Fi.
My ISP provides me 100 Mbps download, but on the secondary router, I can barely get 25-30 Mbps. Measurement with iperf3
between the secondary router and the main one gives me around 75-77 Mbps, which is still far from 100 Mbps the secondary router is capable of (counting the fact I'm trying to measure only LAN speed, so it should be like 94-96 Mbps with 100baseT port).
And one more interesting fact - not so long ago I changed the main router. Before, TL-WR841N was the main one (which is the secondary now). And another TL-WR741ND was secondary. And in this setup everything was perfectly fine, I could reach almost the same speed on the secondary router as on the main one.
So, looks like there is definitely something about the relation between the new router (Archer C7) and the old one (TL-WR841N).
But I have no idea how to troubleshoot this.
I think the fact the new router has 1 Gbps port (8 pin) vs 100 Mbps port (4 pin) for the old one should not cause such an issue and LAN speed between them should be limited to the slowest one - 100 Mbps.
Archer C7 v5 is running on OpenWrt 21.02.1
TL-WR841N v9 is running on LEDE 17.01.7
TL-WR741ND v4 (formerly) was also running on LEDE 17.01.7
Any ideas on how is that possible - everything is running smoothly with no issues but looks like the LAN connection is capped somehow? And everything was nice with the pair of two old TL-WRXXX routers. The cable or any in-between parts are left untouchable.
If needed I can share my configs, but nothing outstanding there. The main router has a pretty default configuration in terms of interfaces/networks (+software offloading). The secondary one is configured exactly as described here https://openwrt.org/docs/guide-user/network/wifi/dumbap.
upd. When I connect my laptop directly instead of a secondary router I can get the full speed of around 100 Mbps. But when connected through Dumb AP the connection gets capped.