[idlmn89]

Hello,

I have a wrt3200acm linksys router and because of changes in my home network the OEM firmware of linksys was not sufficient anymore. So I decided to flash the dd-wrt firmware because I already used it with a tp-link wr1043nd for years.
I configured wlan as follows:

dd-wrt build: v3.0-r40134

Interface: ath0 (5 GHz/802.11ac)
WLAN-Mode: Client
WLAN-Network-Mode: AC/N (mixed)
Channel width: VHT80 (80MHz)
Network configuration: unbridged

Interface: ath1 (2.4GHz)
WLAN-Mode: AP
WLAN-Network-Mode: N/G mixed
Channel width: HT40 (20+20 MHz)
Network configuration: bridged

With this configuration I route the traffic from the ethernet ports and ath1 over ath0 to the actual isp router. So ath0 is used as upstream for all the traffic from ethernet and ath1.
But when I download large files with a client connected to ath1 the download freezes every few seconds for another few seconds.
I chnaged every parameter but the only change that solved the problem was changing the wlan-network-mode from n/g-mixed to n-only. I also tried different former builds of dd-wrt but this wasn't the solution either.
Does anyone now a reason why this happens? I don't know any good reason why the n/g-mixed mode would cause such a behavior.