Cascading router LAN to WAN configuration

I just set up a LAN to WAN configuration but my speed decreased from 600 mpbs to 300mpbs, can this be because of the configuration or is it a normal behavior? Also if the configuration is LAN to LAN the speed is normal.
Both routers support 1gbps lan bandwidth.
I can give more information if needed.

This behavior is typically seen because of hardware NAT not being supported by LEDE usually. It shows as degraded performance from LAN<==>WAN but not on LAN<==>LAN.

Can you elaborate a little bit more about the routers models and how they are connected (I'm assuming that they are both connected on LAN) ? I'm also assuming one of them is TP-WR1043nd v4.

Another way to see this would be "router CPU to anemic for its intended use-case..."

The main router is huawei HG8247H connected directly to the fiber optics cable and the second one is TP-WR1043nd v4 yes. So i connected a lan switch from the first one to the wan switch of the second one. Also the router behaves the same with the stock firmware.

So I might have spoken too fast, maybe the TP-WR1043nd doesn't have HNAT. Thought your 300 Mbps looks like good throughput because SmallNetBuilder rated it around 120 Mbps in 2011, and OpenWrt Wiki has testings done with variations from 122.7, 180 and 210 Mbits. I suspect HW revisions being a factor, since you have v4.

Yup, indeed better rephrasing :wink: