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The Graveyard - Products No Longer Supported => Routers / COVR => DIR-878 => Topic started by: afa3 on January 15, 2018, 05:55:27 PM

Title: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 15, 2018, 05:55:27 PM
[ Thread summary: the DIR-878 works fine with many of my devices, but not my ASUS TM-AC1900/RT-AC68U bridge. Both work fine with other, slower devices. 99% of the time they work OK together, but that's not good enough for streaming video. I tried a lot of experimenting and wasn't able to find a specific reason or a solution. ]

I have a new DIR-878 that frequently drops the 5Ghz connection for several seconds at a time. This is the second unit I've had. I exchanged the first one for the same reason, and the new one is the same - so it doesn't seem to be bad hardware. I've tried everything I can think of with no improvement. Unless someone here has some ideas, this one is going back also.

I notice that MrTriTanium reported issues that sounded similar on his PS4 topic, but no discussion or resolution.

The DIR-878 is replacing an existing AC1200 router that works fine.

I'm in the midwest US. ISP is Spectrum. Cable modem is a Motorola SB6141. I've also tested with no WAN at all, no change.

The DIR-878 is the AP going to an ASUS TM-AC1900 set up as a bridge. Both have up-to-date firmware. AP and bridge are on separate floors, 30 feet apart or so. The bridge shows the DIR-878 signal strength as 5 bars. I'm in a residential neighborhood. The bridge shows no other strong 5Ghz APs nearby. Usually 1-3, all one bar. No other sources of interference that I know of. We have a wireless phone, but it's DECT 6.0 - 1.9Ghz.

The dropouts seem random. Streaming HD MPEG2 video from a local tuner or recording across the 5Ghz typically drops out 2-10 seconds every 5-30 minutes.

The existing AP router never has a problem, but it's connecting at a lower rate.

DIR-878 firmware is now 1.01B04. The same problem occurred with 1.00 and 1.02B01.

Smart Connect is turned off. 2.4Ghz and 5Ghz have different, non-default SSIDs. 2.4Ghz is turned off for testing, same issue either way.

I've tried:
- N only and AC only
- channel width 20/40 vs. 20/40/80
- auto channel selection
- multiple manual channel selections, avoiding the channels found on the bridge scan
- changing AP position a little
- changing AP and bridge antenna orientations
- turned off anything that didn't seem to matter
- other apps/devices on the bridge side

None of the changes made a difference. Also tried medium tx power - no connection at all in that case.

I tried a couple of other client wireless devices. An old 300N bridge seem stable, but at a much lower transmission rate of course. A Dell/Intel laptop also seemed to have occasional issues, but I couldn't set up a similar streaming test over a long period.


Title: Re: ideas for debugging 5Ghz dropouts?
Post by: GreenBay42 on January 16, 2018, 07:35:17 AM
Do you have any 5GHz clients connected to the DIR-878 or is the drop connection issue only happening when connecting clients to the Asus bridge?

Do all clients (2.4 and 5ghz) when connecting to the bridge drop connection?

Do clients that connect directly to the 878 router drop?
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 16, 2018, 08:02:28 AM
Link>Welcome! (http://forums.dlink.com/index.php?topic=48135.0)

Does the same thing happen if you enable Smart Connect?

When SC is disabled, try manual Channel 1, 6 or 11 on 2.4Ghz then try manual channels on 5ghz.


I have a new DIR-878 that frequently drops the 5Ghz connection for several seconds at a time. This is the second unit I've had. I exchanged the first one for the same reason, and the new one is the same - so it doesn't seem to be bad hardware. I've tried everything I can think of with no improvement. Unless someone here has some ideas, this one is going back also.

I notice that MrTriTanium reported issues that sounded similar on his PS4 topic, but no discussion or resolution.

The DIR-878 is replacing an existing AC1200 router that works fine.

I'm in the midwest US. ISP is Spectrum. Cable modem is a Motorola SB6141. I've also tested with no WAN at all, no change.

The DIR-878 is the AP going to an ASUS TM-AC1900 set up as a bridge. Both have up-to-date firmware. AP and bridge are on separate floors, 30 feet apart or so. The bridge shows the DIR-878 signal strength as 5 bars. I'm in a residential neighborhood. The bridge shows no other strong 5Ghz APs nearby. Usually 1-3, all one bar. No other sources of interference that I know of. We have a wireless phone, but it's DECT 6.0 - 1.9Ghz.

The dropouts seem random. Streaming HD MPEG2 video from a local tuner or recording across the 5Ghz typically drops out 2-10 seconds every 5-30 minutes.

The existing AP router never has a problem, but it's connecting at a lower rate.

DIR-878 firmware is now 1.01B04. The same problem occurred with 1.00 and 1.02B01.

Smart Connect is turned off. 2.4Ghz and 5Ghz have different, non-default SSIDs. 2.4Ghz is turned off for testing, same issue either way.

I've tried:
- N only and AC only
- channel width 20/40 vs. 20/40/80
- auto channel selection
- multiple manual channel selections, avoiding the channels found on the bridge scan
- changing AP position a little
- changing AP and bridge antenna orientations
- turned off anything that didn't seem to matter
- other apps/devices on the bridge side

None of the changes made a difference. Also tried medium tx power - no connection at all in that case.

I tried a couple of other client wireless devices. An old 300N bridge seem stable, but at a much lower transmission rate of course. A Dell/Intel laptop also seemed to have occasional issues, but I couldn't set up a similar streaming test over a long period.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 16, 2018, 09:19:10 AM
Thanks for the replies.

Normally the ASUS bridge is the only 5GHz client. I'm streaming from local devices wired to the DIR-878 to devices wired to the ASUS bridge.

I've only connected one 5GHz client at at time, so I don't know what happens if there are multiple 5Ghz clients. I'll try that when I have time.

I've had multiple 2.4GHz clients at the same time as the 5Ghz client, but I haven't watched what happens on the 2.4GHz side at all. Lately I've just turned off the 2.4GHz side while testing.

I tested a N300 bridge as a 5Ghz client (alone), which seemed stable.

I briefly tested a laptop as a direct 5Ghz client (alone). That seemed to have have occasional drops and rough patches but I haven't tried to reproduce that.

Do you have any 5GHz clients connected to the DIR-878 or is the drop connection issue only happening when connecting clients to the Asus bridge?

Do all clients (2.4 and 5ghz) when connecting to the bridge drop connection?

Do clients that connect directly to the 878 router drop?

I believe the same thing happened with SC enabled when I first set it up. One of the first things I tried was turn that off and split the SSIDs.

I've tried many channel settings on 5GHz.

Haven't played with the 2.4GHz settings, but also haven't seen a problem with 2.4Ghz.

Link>Welcome! (http://forums.dlink.com/index.php?topic=48135.0)

Does the same thing happen if you enable Smart Connect?

When SC is disabled, try manual Channel 1, 6 or 11 on 2.4Ghz then try manual channels on 5ghz.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 16, 2018, 09:24:35 AM
Please try SC enabled again with the NetGear bridge. Then test the ASUS Bridge.

Is there any MU-MIMO options on this router? If there are, try to disable them as well and test.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 16, 2018, 01:46:19 PM
I turned back on SC and connected the ASUS bridge at both 2.4Ghz and 5Ghz. This bridge shows both bands. If I connected on a band, it stayed on that band even through a bridge reboot. So I'm not sure SC at the AP was doing any band switching.

With the bridge connected at 2.4Ghz, it showed a 288.5 Mbps connection rate. Streams were slow to start up. Did see a 5-10 second dropout after 20 minutes of steady signal. The 2.4Ghz dropout might or might not be the same issue. The bridge scan shows we have a bunch of 2.4Ghz APs in the area, so that could pretty easily be interference.

With the bridge connected at 5Ghz, the bridge showed a 1300Mbps connection rate. As usual, streams started quickly but had a big dropout after only a few minutes.

In both cases, I had a laptop directly connected on the same band. During both dropouts the laptop seemed unaffected. It's hard to be sure, since I was just doing browsing on the laptops, not continuous streaming. In both cases, however, the dropout seemed to be just on the bridge connection, not the whole band.

I don't have a NetGear bridge. The ASUS is the only one I'm normally using. I previously tried a old N300 (Linksys WRT320N) bridge to see what would happen, but that's not in the same class and it's an 'ashtray' with no external antenna. It showed connection rates varying between 170-300 Mbps (it's running DD-WRT and dynamically shows connection rate).

The DIR-878 does have MU-MIMO, but I see no option to turn it off.

Please try SC enabled again with the NetGear bridge. Then test the ASUS Bridge.

Is there any MU-MIMO options on this router? If there are, try to disable them as well and test.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 16, 2018, 02:00:05 PM
I'm wondering if this minor drop out is the router changing channels due to what you say you have other neighbors near by. Could be a possibility. Also could be the router attempting to handle the bridge and the router is doing something, thus causing a intermittent stop of the bridge. After the drop out, does the bridge get reconnected and do you have access thru the bridge or do you have to reboot the bridge or router to gain access again?

Ok, I presumed it was NetGear bridge. I presume the Linksys bridge max connection rate is 300Mb.

Ok, wonder if that something that D-Link could add to the router. If you don't have any MIMO supporting devices, could be something that could be disabled. However depends on how they set up the wireless HW and drivers to operate.  ???
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 17, 2018, 07:31:18 AM
Is there any way in the DIR-878 UI to see the current, actual transmission rates? I can plot the data throughput under Management->Statistics, but I don't see the connection transmission rate anywhere.

I found something weird that might shed some light on this. When connected to the DIR-878 AP, my ASUS bridge is reporting incorrect connection rates. When paired with my existing AP, it reports the expected connection rates. My other devices connected to the DIR-878 report the expected connection rates.

So the combination of the DIR-878 and the ASUS TM-AC1900 is the only one that shows this behavior, and it's the only combination that repeatedly drops out. Maybe the rate reporting on the ASUS is just a glitch in the logging, but I wonder if there is some strangeness in the rate negotiation between the DIR-878 and the ASUS.

It turns out that on the ASUS TM-AC1900, the _actual_ transmission rate is buried in a log file. The main UI page apparently shows the maximum possible rate, not the actual transmission rate. You have to dig down to the wireless log to find the actual status.

Watching the actual receiving rate on the ASUS shows strange values when connected to the DIR-878. As far as I can tell, it always shows a 6Mbps or 24Mbps rx rate. This is true even when streaming or doing a file copy. The actual data throughput during a file copy is much higher, but the log always shows 24Mbps.

When I connect to the DIR-878 with the old N300 bridge or with a laptop, the receiving devices show actual connection rates in the 150-450 Mbps range.

When I connect the ASUS bridge to my existing AP, the ASUS usually shows 250-470 Mbps rates. This is confirmed by the rate shown in the AP UI.

I have two snapshots of the ASUS wireless "log" (really it's the current status, not a log). One is while connected to the DIR-878. The other is while connected to my existing AP, a ZyXEL 650X AC1200. I don't see a way to attach them to a post here. If it would be helpful, I can just post them (they're not that big).

What would be better is to show the connection status from the DIR-878 side, but I don't see a way to do that.




Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 17, 2018, 07:57:14 AM
Thats one thing I do miss is the connection rate seen by the router with devices. Something D-Link had in there older model routers and UI. Since the new UI came in a few years ago, they stopped using the connection rate feature. Don't know why. Was a good way to tell what rates were being seen. Wish they would bring that back.

Adding Screenshots In A Post (http://forums.dlink.com/index.php?topic=58120.0)


If your ASUS device seem to be exhibiting issue. I would attempt to try that device with a different router to see if the problem follows. Could be a bad unit or a possible problem between the ASUS and the DIR router... :-\
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 19, 2018, 10:08:10 AM
Curious, what channels are you seeing being used by the 878 when SC is enabled?
Please post a screenshot if you can while using a wifi scanner of sorts.

Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 19, 2018, 11:37:47 AM
It varies. There don't seem to be any nearby strong 5Ghz radios, so it's pretty much free to pick.

I think I remember it using 36 and 161. I've manually set it to 44 and several others (with SC off).

If I start it up again, I'll get a screen shot.

At this point, I'm going to return it unless someone can confirm a specific issue and fix. I think the hardware is good, but the firmware has compatibility issues with some devices. The PS4 thread here and the "A few questions" thread in the DIR-882 forum both talk about 5Ghz problems with some devices and not others. That's what I'm seeing also.

Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 19, 2018, 11:41:23 AM
You could return it and try another. Possible that the HW is faulty, however I don't think so.
Another test would be to try a different ASUS or non ASUS wireless device and see if something happens.

At this point. Running out of ideas. I would log a problem with D-Link support as well to be sure they are aware of this.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 19, 2018, 11:51:19 AM
Thanks for all the suggestions.

I've already exchanged once. First one was the same.

I tried a N300 bridge and laptop directly connected and haven't seen the same issue.

I'll log a support call and reference this thread.

FWIW, here are the status dumps from the ASUS TM-AC1900 while connected to the DIR-878 and my existing ZyXEL 650X AC1200. Maybe they will be of some help.

ASUS TM-AC1900 bridge to DIR 878 AP (has dropouts, reported rx rate never goes above 24m):

SSID: "xyz"
RSSI: -48 dBm   SNR: 0 dB   noise: -92 dBm   Flags: RSSI on-channel    Channel: 161/80
BSSID: xx:xx:xx:xx:xx:xx   Capability: ESS WEP ShortPre
Supported Rates: [ 6(b) 9 12(b) 18 24(b) 36 48 54 ]
WPA:
   multicast cipher: TKIP
   unicast ciphers(2): TKIP AES-CCMP
   AKM Suites(1): WPA-PSK
   No WPA Capabilities advertised
RSN:
   multicast cipher: TKIP
   unicast ciphers(2): TKIP AES-CCMP
   AKM Suites(1): WPA-PSK
   Capabilities(0x0000): No Pre-Auth, Pairwise, 1 PTK Replay Ctr1 GTK Replay Ctr
VHT Capable:
   Chanspec: 5GHz channel 155 80MHz (0xe39b)
   Primary channel: 161
   HT Capabilities: 40Mhz SGI20 SGI40
   Supported MCS : [ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 ]
   VHT Capabilities:
   Supported VHT (tx) Rates:
      NSS: 1 MCS: 0-9
      NSS: 2 MCS: 0-9
      NSS: 3 MCS: 0-9
      NSS: 4 MCS: 0-9
   Supported VHT (rx) Rates:
      NSS: 1 MCS: 0-9
      NSS: 2 MCS: 0-9
      NSS: 3 MCS: 0-9
      NSS: 4 MCS: 0-9
WPS: V2.0 Configured

Mode   : Media Bridge

Stations List                           
----------------------------------------
MAC               Associated Authorized    RSSI PSM SGI STBC Tx rate Rx rate Connect Time
xx:xx:xx:xx:xx:xx Yes        Yes         -48dBm No  Yes Yes       6M     24M 00:09:59



ASUS TM-AC1900 bridge to ZyXEL 650X AC1200 (no dropouts, reported rx rate hovers around 468 while transferring):

SSID: "xyz"
RSSI: -56 dBm   SNR: 0 dB   noise: -92 dBm   Flags: RSSI on-channel    Channel: 44/80
BSSID: xx:xx:xx:xx:xx:xx   Capability: ESS WEP ShortSlot
Supported Rates: [ 6(b) 9 12(b) 18 24(b) 36 48 54 ]
RSN:
   multicast cipher: AES-CCMP
   unicast ciphers(1): AES-CCMP
   AKM Suites(1): WPA-PSK
   Capabilities(0x0000): No Pre-Auth, Pairwise, 1 PTK Replay Ctr1 GTK Replay Ctr
VHT Capable:
   Chanspec: 5GHz channel 42 80MHz (0xe22a)
   Primary channel: 44
   HT Capabilities: 40Mhz SGI20 SGI40
   Supported MCS : [ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ]
   VHT Capabilities:
   Supported VHT (tx) Rates:
      NSS: 1 MCS: 0-9
      NSS: 2 MCS: 0-9
   Supported VHT (rx) Rates:
      NSS: 1 MCS: 0-9
      NSS: 2 MCS: 0-9
WPS: V2.0 Configured

Mode   : Media Bridge

Stations List                           
----------------------------------------
MAC               Associated Authorized    RSSI PSM SGI STBC Tx rate Rx rate Connect Time
xx:xx:xx:xx:xx:xx Yes        Yes         -56dBm No  Yes No        6M    468M 00:08:51


Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 19, 2018, 11:53:42 AM
Thanks for this info. Seems like this model router doesn't like the ASUS bridge or the bridge doesn't like the router.

I'll pass this on to D-Link for review. Any chance of trying a different model ASUS bridge? Wondering if all ASUS bridges are seeing this issue with this router.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 19, 2018, 12:00:26 PM
One other thing you could try if you want to. It would help to narrow down weather if this is a FW issue. There is DD-WRT FW support for this model router. Could try it and see if the ASUS behaves any differently...
Can always come back to D-Link FW after testing this...
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 19, 2018, 12:18:04 PM
Sent an email to D-Link support. The case ID is C7081296.

I thought about trying DD-WRT, but the comments on the DIR-878 thread say it might have issues. I still might try it if I have time this weekend.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 19, 2018, 12:21:09 PM
Ok, I've passed this on to D-Link for review.

Keep us posted if you get any info.

Review this before migrating to WRT:
http://forums.dlink.com/index.php?topic=72749.0 (http://forums.dlink.com/index.php?topic=72749.0)

I'll be around if you need help. There has been known issues with WRT globally for DIR series router. They fixed that this last Dec 2017.
So you might give most recent WRT a try:
https://www.dd-wrt.com/phpBB2/viewtopic.php?t=310376&highlight=dir878 (https://www.dd-wrt.com/phpBB2/viewtopic.php?t=310376&highlight=dir878)
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 21, 2018, 02:01:37 PM
I tried DD-WRT. It seems to have issues of its own, so it's not a solution for my use.

DD-WRT would not stream live TV from my HDHomeRun tuner for more than a few seconds before dropping. It wouldn't even do it across wired connections. This may have to do with DNLA multicast or UPnP support. I turned on UPnP, which is off by default. I didn't see any DD-WRT options for multicast, so I gave up on it.

The ASUS bridge also often had trouble even seeing the DIR-878 on 5Ghz. This seemed to vary with channel and channel width settings.

I tried both r34311 and r34578. Same streaming issue on both.

Once connected, DD-WRT otherwise seemed OK. File copies and surfing were good. I did some streaming of recorded video, which was was good for the time that I did it. I didn't see the same dropouts as with the stock firmware, but I didn't test it for a long period.

Flashing back and forth was easy. Thanks for the instructions.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 21, 2018, 02:09:40 PM
Ok, I was hoping. Well, seems like there maybe an issue with FW and this particular model bridge your using.

Only think I might try would be to try a different model DIR router if there is one available. See if possible a different model would work.

I would email this to support and give all specifics to what you tried and give info to the bridge you use and having problems with. I believe this needs to be reviewed in D-Link labs.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: afa3 on January 24, 2018, 11:25:16 AM
A bit more information, but no change in the results. I'm returning the DIR-878.

The ASUS TM-AC1900 bridge I'm using is a T-Mobile version of the RT-AC68U. Up until now, I was using the T-Mobile version of firmware.

I flashed to the ASUS RT-AC68U firmware. Dropouts are still there.

I also picked up a laptop WiFi AC1200 USB dongle. That works fine with the DIR-878.

So basically, the DIR-878 and ASUS don't work reliably together. Both work fine with other, slower devices. I don't have a third AC1900 device to try, so I can't narrow the problem down to one or the other. All the other devices I have are AC1200 or N.

Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on January 24, 2018, 11:58:12 AM
Thanks for the additional info. I presume there is a problem between these two Mfrs. The 878 is still being reviewed and FW being developed. Hopefully it will change in the future.

Good Luck.
Title: Re: ideas for debugging 5Ghz dropouts?
Post by: FurryNutz on March 14, 2018, 07:59:21 AM
FYI: http://forums.dlink.com/index.php?topic=73509.0 (http://forums.dlink.com/index.php?topic=73509.0)