IPv6 WiFi bad performance

[ccc1]

Asus router (RT-AX1800U) already updated with latest firmware.

1) with IPv6 enabled - Wifi connection seeing high packet retransmission, but wired connection no issue with performance. If surfing site (site has IPv6 address) on wifi e.g. www.google.com, ipv6.google.com, www.youtube.com loading very slow with some parts of page not loading. If surfing site (site has only IPv4 address) on wifi, no problem with browsing. IPv6 connectivity fine working (ISP with another router from another vendor tested IPv6 is good so not issue with ISP) but just cannot browsing performance is very bad for some major sites (slow and hang and high retransmission) on ASUS router with IPv6 enabled.

2) with IPv6 disabled - Wifi and wired connection all working fine.

Tried tuning MTU and MRU for WAN values down until 1280 (minimum for IPv6 to work) still same sometimes improvement for some major site but does not fix for all above major sites.

Suspect issue is with ASUS router IPv6 implementation does not support path MTU discovery thus causing packets to be dropped and thus high retransmission.

[ccc1]

Thanks @SiriusDark, no problem. I finally used a TPLink to act as AP, connected to Asus router LAN port, and IPv4 and IPv6 worked great. So it proofed it is not hardware issue, since IPv4 over WiFi was working fine, only IPv6 over WiFi was having very bad performance. 

Unfortunately even with so much being done to proof the case, ASUS support could not help but only ask to wait for next firmware release. Took a brave step, and installed Openwrt on the Asus router and it was a saviour, everything worked fine. Sad that first time trying Asus product and it was a real disappointment that focus too much on a nice looking GUI and AiMesh, but forgot to maintain a working core functionality of the product - packet switching and routing.

[ccc1]

Forgot to add that PPPOE with IPv4 and DHCPv6-PD had problematic performance for IPv6 over WiFi. Tried many ways including putting a TPLink to handle PPPOE with IPv4 and DHCPv6-PD towards ISP, and switched Asus to Native IPv6 with passthrough connected to TPLink LAN port, and tested IPv4 and IPv6 over WiFi then worked.  That helped to proof the hardware was not faulty but rather was firmware bug. Hope this information helps others to not waste too much time troubleshooting IPv6 over WiFi and Asus will release a fix soon.

[ZenBot]

Thread automatically closed due to inactivity. If the reported issue has not been resolved or you require further assistance from one of our moderators, please create a new thread and we will be with you shortly.