Laggy YouTube/Prime stream on 2802i/2702i with Mobility Express.

sardarjion · ‎06-20-2023

Hi All,

I would like some help on how to proceed in debugging the issue below for example, what type of logs etc. to collect and analyze.

Issue: I have 2802i in mobility express mode with 8.10.185.0 version installed. Another 2702i connects to this ME. Both APs connect to cisco rvs4000 directly. No switches or couplers etc. in between. I have Samsung smart TV with youtube app. Whenever, I watch a video on Youtube, I see the videos are blurry and videos play on 240p/360p. The mode for video is set to Auto in settings. I ensured the SSID is only 5GHz and no other client is connected on network to rule out other devices hogging the bandwidth. I tried both 2802i or 2702i connecting to TV but the video is laggy and poor quality.

Now, I switch the configuration to WLC 2504 (8.5.182.7) with both these APs in local mode. The APs along with WLC connect directly to rvs4000 LAN ports. The issue goes away completely and the video quality automatically goes to 720p or 1080p. I tried with both 2802i and 2702i and quality remains same i.e. excellent.

In both the cases, I didn't play with data speed settings and keep it default. SSID is both case have same name and only 5Ghz. I thought it will limited to just Youtube but saw this on Amazon Prime and Netflix as well. Then I thought maybe the apps on TV are buggy and then took firestick and tried and same results.

On Youtube, there is option for "stats for nerds" and it shows the buffer graph. I saw in mobility express mode the buffer would continuously deplete and I would see choppy video and then buffer files up again but on WLC 2504 it never goes down and video runs properly.

Also, I ran speed test on both models and it shows 550mbps download but somehow video is still a problem in ME mode.

My internet speed is 500mbps/20mbps.

Leo Laohoo · ‎06-20-2023

I suspect the issue is with the 2800. Try the following:

Turn off 802.11ac
Set Channel-Width 20- or 40 Mhz
Disable WMM

The 2800/3800/4800/1560 family of APs have MARVALL radio chipsets. In AireOS, the firmware of the MARVALL chipsets are known to be causing issues (long list of Bug IDs) and Cisco has been reluctant to fix the bugs (plural) and the "solution" is to use the new 9800.

sardarjion · ‎06-21-2023

I tried all the suggestions but I still see poor quality video in mobility express mode.
somehow I don’t see this type of fluctuations when I download a big file.

Leo Laohoo · ‎06-21-2023

Disable all the radios of the 2800. All of them.

Are the YT videos bad with all the 2800 and their radios disabled?

sardarjion · ‎06-22-2023

Which radios are you referring here? If I disable all then Wi-Fi won’t work isn’t it ? Or am I missing something?

Leo Laohoo · ‎06-22-2023

@sardarjion wrote:
Which radios are you referring here?

Just as a test, disable the radios to all the 2800 (or admin disable the AP). This will force all wireless clients to join the 2700. See if YT are still lagging.

sardarjion · ‎06-23-2023

Oh that one I already did. So I made sure I tv connect to 2702i and moved the 2802i to another room and even disabled wifi . The problem persists. However, I use the same 2702i/2802i with WLC and everything is good.

I think there has to be some logs which I can collect to debug.

Leo Laohoo · ‎06-23-2023

Is the TV connected on 2.4 Ghz or 5.0 Ghz?
Do a parallel test with a non-Android device, like an iPad or something. Use a different YT stream channel.

sardarjion · ‎06-23-2023

I tried with SSID on 2.4ghz and 5ghz only to make sure it is not frequency issue. Both frequencies have same issue when in mobility express mode.

I have iPhone 13 and I don’t see that issue on YouTube or prime app. I tried it on windows 10 and MacBook also and don’t see the issue on mobility express. Just the tv app but then I don’t see this on WLC so thinking it is not app issue. I tried my phone hotspot from iPhone and I don’t see the issue so tv app seems to be ok.

Leo Laohoo · ‎06-23-2023

@sardarjion wrote:
I have iPhone 13 and I don’t see that issue on YouTube or prime app. I tried it on windows 10 and MacBook also and don’t see the issue on mobility express. Just the tv app but then I don’t see this on WLC so thinking it is not app issue.

It does sound like an app issue on the TV. And you are seeing this issue if the TV is connected to the WLC and the issue it not just YT but Prime app. Is this correct?

What is the RSSI and SNR value of the TV (from the AP)?

And when you say "lag", you mean it buffers all the time, right?

Does the TV support ChromeCAST?

sardarjion · ‎06-24-2023

I don’t think so it is app issue. As mentioned when connected over WLC, phone hotspot and even my old tplink archer c7, app works perfectly and only goes bad with mobility express.

when I say bad, it means picture quality remains at 240p/360p instead of best available option of 720p or 1080p. Plus, video keeps pausing for buffering even with this low quality video.

I am thinking mobility express is broadcasting something in Wi-Fi signal which is limiting speed on tv because the app won’t know which type of AP is connected.

on side note, I have Aruba 535 also and it worked perfectly fine there in instant ap mode which is similar to mobility express mode.

the ap is just below the wall mounted tv but I can check and get back the rssi reported in Cisco UI.

i have fire stick so can try YouTube on that and see how it goes.

Leo Laohoo · ‎06-24-2023

Can you try and turn the 2700 into an autonomous AP?

The reason why I am suggesting this is because I know (or have compiled) of some bugs that are exclusive to the 2800/3800/4800/1560 model of APs. Majority of the bugs are caused by the MARVALL radio chipsets found in generation of APs. When the bugs are triggered, the AP will randomly drop packets.

Circling back, if an 2700 in autonomous IOS works, then it will prove that the issue is the 2800.

List of bugs exclusive only to the 2800/3800/4800/1560 family of APs can be found HERE.

sardarjion · ‎07-03-2023

I tested with 2702i autonomous mode with version ap3g2-k9w7-xx.153-3.JBB5 and no problems at all. I had kept the SSID to 5Ghz which is same as ME configuration. I even connected my iPhone 13 to same SSID and played Netflix on it along with YouTube on TV and encountered no issues on both phone and TV.

For mobility express, I went back to 8-3-150-0 version and still saw the issue.

Leo Laohoo · ‎07-03-2023

Are you able to borrow a Catalyst 9k AP and test?

If the Catalyst 9k works, the autonomous AP works then it somewhat proves the issue is with the 2800.

sardarjion · ‎07-03-2023

I don't have catalyst AP :-(, 2802i is my newest toy. Wish there was some site where I could rent it to try.