Hi,

I have a 2927 (fw 4.3.2) and was using it happily (dual wan) with Virgin 350 business & a VDSL line... But Virgin sucks and CityFiber just lit up here so now on 950/950 FTTP with the virgin stuff as a backup on WAN2 (until I get out of my contract period).

Anyway my CF ISP (Giganet) offers both IP4 (single static) and ipv6 static /64. My first foray with IPv6 but as I run some web servers and other things, its handy as a single static IPv4 isn't really enough.

Initially I didn't bother with IPv6 and all was good (>850mbit each way - all working nicely). Then I enable IPv6 to learn and play. At first it seems OK but on closer inspection, I have severely limited the bandwidth with IPv6 enabled - CPU usage spikes >88% and throughput is in the range 250-350mbit both directions). If I use an IPv4 speed test, it still gives me >850 down (cpu usage < 5%) but up seems to be only getting 300mbit and again stupid high CPU usage.

So it seems that with IPv6 enabled, hardware acceleration is not working for anything but IPv4 down (incoming)???

The ISP supplied Technicolor router does not suffer this problem so I'm confident its not an ISP issue.

Yesterday I found the 4.4.0 firmware on the .com (no release notes so was a little worried but gave it a try). Upgraded using the all (not rst) but it was a mess after that - the WAN2 I/F (static IP) didn't detect a connection at all, and settings would get lost. Maybe I should run the RST and start from scratch (ouch!) or maybe the fw is buggy and that's why its not on the UK site. However, I was still suffering similar issues with HW accel but was unable to completely test it and rolled back to fw 4.3.2 (using RST and then applying my old backup)

Are there known issues with hardware acceleration when in IPv4/IPv6 dual stack? I'm not reliant on IPv6 so I could switch it off again but its interesting stuff to learn and make sure my own software (and servers) is properly compliant!

I saw issues with IPv4 performance when upgrading to 4.4.0, rolled back to 4.3.2, and release notes have since been updated, suggesting to disable dataflow, seems a regression in the new version.

Cant comment on IPv6, but common sense tells me turning on any feature will consume more resources, and maybe consuming too much?

Good video here discussing hardware acceleration, about 30mins in shows some command to run to show how utilised the hardware acceleration is:

https://www.youtube.com/watch?v=vCZZ15fa2nU

Draytek support confirmed that IPv6 is not hardware accelerated.
Of course, IPv6 does not need/use NAT so it shouldn't need NAT acceleration - but something is still amiss if IPv6 is taking >80% CPU usage and restricting me to 1/3rd of my line speed!

They gave me 4.4.2 RC1 to try but that failed to make any difference and also fell over for other (firewall related) issues. Still some work to do on 4.4.x it seems!