RT-AC88U and DFS

[Hawk]

Howdy folks, I am planning to upgrade later this year, I want to ask does rt-ac88u support DFS channel selection.

Also for the owners of rt-ac88u, what is your experience with this router? good and bad both welcome.

 

[Deleted member 22229]

I have the AC3100 same exact router except only 4 lan ports and at least in the USA it does not support DFS channels. 1-11 on 2.4ghz and 36-48 low band and 149-161 high band for 5ghz. As far as how i like this router rock solid performer from day one.

 

[RMerlin]

DFS channels only supported in Europe (AFAIK).

As for user feedback, it's in that thread: http://www.snbforums.com/threads/rt-ac88u.27704/

 

[Gerry Wasiluk]

Howdy folks, I am planning to upgrade later this year, I want to ask does rt-ac88u support DFS channel selection.

Also for the owners of rt-ac88u, what is your experience with this router? good and bad both welcome.

Not good as a media bridge. IMVHO, avoid for now (as a media bridge).

 

[Hawk]

thanks guys, for helpful feedback. Regarding DFS I have bell fibe wireless receiver and it support DFS so is it something to ASUS. According Broadcom it support DFS.

Also want your help regarding rt-ac68u, channel is set to 149 for 5 ghz but after using for five days straight without reboot5 ghz loose power by -10 dbm which can be cured if reboot. Is this something expected?

 

[L&LD]

thanks guys, for helpful feedback. Regarding DFS I have bell fibe wireless receiver and it support DFS so is it something to ASUS. According Broadcom it support DFS.

Also want your help regarding rt-ac68u, channel is set to 149 for 5 ghz but after using for five days straight without reboot5 ghz loose power by -10 dbm which can be cured if reboot. Is this something expected?

What firmware are you running? What devices report this drop?

 

[Hawk]

What firmware are you running? What devices report this drop?

380.57_0 by Eric, all device are affected and only in 5GHZ. Example I reset router and is in position X where I am getting -44dbm after router running for few days (less than a week) it is reporting -55 or lower. If I reset router it goes back to -44 and then rinse and repeat.

Test purpose I use Samsung Galaxy 5 and I already have done factory reset 3 times using WPS key while turning router on and also reconfigure from scratch.

 

[RMerlin]

Do actual speed tests, don't just rely on signal power. That can vary based on power management, client position, etc...

 

[Hawk]

Do actual speed tests, don't just rely on signal power. That can vary based on power management, client position, etc...

Okay let me run speed test again and see what happens.

 

[Hawk]

I can confirm speed drop do occur on 5GHZ channel. Last night I restarted router and did it again and it is working as expected for time being.

 

[tgm1024]

^^^^Many have noticed such weirdness.

I've been reading about similar and various problems with DFS and TPC, and I'd like to know if the RT-AC68U can disable DFS (and possibly TPC, but that's a later experiment).

I'm reasonably close to a small airport, and even if the airport is radar-less, the incoming planes are not. If my router has chosen the DFS-required frequencies, then it can cause a lot of weird shutdowns from each of the clients, resulting in dropouts and odd-ball delays. And man oh man this connection behavior is starting to drive me nuts.

Some seem to be complaining about the Broadcomm SoC currently being used by a multitude of manufacturers.

In any case, DFS on many routers is simply not a bullet-proof implementation yet.

BUT, where in the AC68U settings do I control this? By simply chosing a bandwidth of 40Mhz instead of 20/40/80? Or in conjunction with turning off one of the other "auto" settings?

Thanks!

 

[Deleted member 22229]

BUT, where in the AC68U settings do I control this? By simply chosing a bandwidth of 40Mhz instead of 20/40/80? Or in conjunction with turning off one of the other "auto" settings?

You can't control it it's automatic. To avoid issues simply pic a non DFS channel instead of auto.

 

[tgm1024]

You can't control it it's automatic. To avoid issues simply pic a non DFS channel instead of auto.

The router gives me control (at least by it's UI) over a bandwidth (20, 40, 80), regardless of channel. Looking at the frequency chart online, AIUI, this potentially lets me choose a non-DFS channel that spills over into DFS channels (radar, etc.) if the bandwidth is too wide. This will cause a quick shutdown of both AP and adapters the moment radar shows up (either by the airport or the aircraft themselves).

Again, AIUI. Did I err somewhere in this?

 

[ColinTaylor]

Again, AIUI. Did I err somewhere in this?

Probably. What exactly are you asking for?

It sounded like you were asking how to stop the router's DFS channel switching ability. i.e. Your router is on channel 100 and detects radar. It will switch channels, you can't stop this it's automatic.

If you want to stop the router changing channels manually select a non-DFS channel.

No, non-DFS channels do not spill over into DFS channels (well, ignoring 160MHz bandwidth ). Although I admit the channel numbering method in the GUI is misleading.

 

[tgm1024]

Probably. What exactly are you asking for?

It sounded like you were asking how to stop the router's DFS channel switching ability. i.e. Your router is on channel 100 and detects radar. It will switch channels, you can't stop this it's automatic.

If you want to stop the router changing channels manually select a non-DFS channel.

I have. Again, I'm talking about what can be reached even from non-DFS channels.

No, non-DFS channels do not spill over into DFS channels (well, ignoring 160MHz bandwidth ). Although I admit the channel numbering method in the GUI is misleading.

Thanks (!!!!!), yes, that addresses what I'm getting at. However, and perhaps this is why I'm at war with wikipedia so often, the implication in their chart is that the bandwidth is always centered on the base frequency (similar to how the 20Mhz's are in that chart of yours.)

In that chart channel 50 reaches as far low as 5170Mhz. That's a DFS channel reaching all the way down to channel 36 or so.

Also, as you mention it seems that the 160Hz breaks free. Perhaps that's the warning I was reading about.

But to be clear, in the low channels, your diagram is correct? That the 40's and 80's always reach within the non-DFS low channels and never reach the DFS channels?

 

[tgm1024]

Also that chart (https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_.28802.11a.2Fh.2Fj.2Fn.2Fac.29) shows specific bandwidths for the various channels. How can that be if I can choose my own width?

 

[ColinTaylor]

But to be clear, in the low channels, your diagram is correct? That the 40's and 80's always reach within the non-DFS low channels and never reach the DFS channels?

Yes that diagram is correct. What the Wikipedia chart does not mention is that when you choose a 40MHz or 80MHz channel in your router's GUI you are actually specifying a 20MHz primary channel. The other channels used by 40MHz and 80MHz bandwidth are automatically calculated from that.

Remember that even if you set you router to 80MHz it still has to be compatible with 20MHz and 40MHz clients.

This has been explained here, here and here.

 

[tgm1024]

Yes that diagram is correct. What the Wikipedia chart does not mention is that when you choose a 40MHz or 80MHz channel in your router's GUI you are actually specifying a 20MHz primary channel. The other channels used by 40MHz and 80MHz bandwidth are automatically calculated from that.

Remember that even if you set you router to 80MHz it still has to be compatible with 20MHz and 40MHz clients.

This has been explained here, here and here.

Awesome. Thanks!