Hi,
I've recently upgraded to 100 mbps down and 10 mbps up Internet connection (FTTH). speedtest shows around 90-100 mbps using Ethernet. I have an RT-AC68U running .55 merlin in AP mode . i am able to get only 60 mbps on wireless (including 5ghz). I do the test in the same room with the AP. Are there any settings i can play with ? I am sure this kinda problems has been addressed before. So if you can point me in the right direction that'd be great.
I also have an RT-68U (currently .56 beta1), and I've got a 100/20 on a 100MB Ethernet to GB Fiber backbone Internet connection and testing with speedtest.net easily get about 97mbs (My ISP's considered top end for throughput, all things considered), on wired side, and about 80+mbps on 5GHz wireless (with WPA2 Enterprise and a 4k key) on any given day. And this is after significant testing and tweaking that got me no more than back to the default settings with no improvements.
I live in a highly wifi congested metro area where there are about 20-30+ active SSID's around me at any given time of day. So the first and foremost problem that occurs that cause wireless performance problems is that WiFi was never designed to accommodate such highly congested channels. This coupled with the fact that the newer, higher speed N & AC protocols gain their higher speed by grouping or bonding channels. (This is what the x+y or 40/80 means in the wifi status flyover, it's the main channel + expansion channel). On 2.4GHz in N mode, this problem gets worse because with expansion channels considered, you only have effectively three channels to work with (1,6,11). In my environment there are no less than 4 if not 10+ SSID's stacked on each of these channels, with many ending up on 11 because auto-channel mechanisms cannot handle highly congested environments. They make one pass for a clear channel and stop when they hit the end of the list. So if a clear channel is not found, you could find your wireless stacked on the end channel with all your neighbors whos routers also could not find a clear channel, and then non-N capable routers sprinkled in the in between channels, which then renders the expansion channels occupied, thus never able to achieve more than single channel bandwidth. There are fewer 5Ghz SSID's but I've been seeing more and more pop up over time, and seeing more and more intermittent speed issues as well as they try to find an open channel.
Now herein lies the big rub that is most likely the cause of why people see slower or erratic wifi throughput vs. wired connection; the use of the expansion channel to achieve higher bandwidth is contingent on the channel being not busy. If the expansion channel is seen as busy, the protocol will automatically fall back to single channel mode & bandwidth. (There is no such thing as forcing the use of expansion channels, at least on 5GHz. Protocol spec requires fall back if expansion channel is busy)
This problem get's worse, at least on the RT-68U if you enable mac filtering as with mac filtering the router no longer will recognize traffic from other routers and thus breaks the auto channel mechanisms. This is one of the reasons for manually setting your channel. So with mac filtering enabled and control channel set for auto, and other routers near you also mac filtering so they can't see you, you can easily end up on a highly congested first channel. (For the RT-AC68U on 5GHz with mac filtering enabled, I see it stop at the first channel of 149 even though I can see other SSID's on the channel. But disable mac filtering and auto-channel then sees the channel is occupied.)
So before you look for tweak settings that can cause you to spend hours getting nowhere, I would start with evaluating your wifi environment for congestion problems that may be causing your signal to fall back to single channel mode, and or limiting available time on the channel. And keep in mind this isn't about what your devices see, but what your router sees. Use the Wireless -> Site Survey (with mac filtering off) to get an idea of what your router is seeing.
Another obvious indicator that you may be have expansion channel issues is to go to your routers System Log -> Wireless Log page and look at the rx/tx speeds while transferring data. If you don't see speeds higher than 54/60 on an AC connection, either your device doesn't support multiple AC streams (not all AC devices are created equal), or the more likely cause being the expansion channel is seen as busy by the router and it's falling back to using a single channel, thus the lower than expected bandwidth.
Anyway, the best results I've achieved is to manually set my control channel to a channel that is not only as clear as possible, but that the nearby expansion channels are also clear and yet I still get occasional speed degradation that always comes back to some neighbor landing on or near my channels.
Hope this helps.
