Jitter problems

Adrian4
Head in the Cloud

Jitter problems

Hello,

 

Does anyone have experience with high jitter? I have a couple of users having such a bad time with VOIP we have had to hard wire them in for the time being.

When I run speed tests, they each have 50-60 jitter consistently.

Oddly, when I put my laptop right next to theirs and run the same test, time is usually below 1, sometimes it jumps to 5 and very occasionally it might get to 20.

but theirs is around 60 every single time. 

We all use the same wifi adaptor with the same driver version. Same version of windows, same network, same AP.

Network traffic/usage is not particularly high at the moment. We have 2,  1Gbps internet lines coming in to two MX devices. But I am not sure the network is the issue as it doesn't seem to be effecting me.

The jitter they get is consistent no matter where I roam in the building, so its not their local AP which I was originally suspecting (I rebooted it anyway for good measure).


Any ideas?

13 Replies 13
alemabrahao
Kind of a big deal
Kind of a big deal

How many users on average per access point?

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

Please, if this post was useful, leave your kudos and mark it as solved.

Here you can find some tips.

.https://documentation.meraki.com/MR/Wi-Fi_Basics_and_Best_Practices/What_is_Jitter%3F#WAN

 

https://documentation.meraki.com/General_Administration/Tools_and_Troubleshooting/Troubleshooting_Cl...

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

Please, if this post was useful, leave your kudos and mark it as solved.

thanks, but I am trying to figure out why two specific laptops have a consistently high jitter where other laptops in the same environment, on the same AP,s same hardware and drivers, are not getting that issue.

alemabrahao
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Kind of a big deal

And I would try to check the links sent to further troubleshoot.

You didn't provide enough details.

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

Please, if this post was useful, leave your kudos and mark it as solved.

I was trying to avoid a wall of text. If you let me know specifically what details might help I can provide.

alemabrahao
Kind of a big deal
Kind of a big deal

Taking a closer look at what you reported here are some considerations., here are a few potential causes and solutions for high jitter:

 

Network Congestion: This is one of the most common causes of jitter. If your network is congested with too much traffic, it can lead to increased latency and jitter. You mentioned that network usage is not particularly high at the moment, but it might be worth checking if there are specific times or conditions under which the jitter increases.

 

Hardware Issues: Old or outdated hardware can also cause jitter. Even though you mentioned that all users have the same wifi adapter and driver version, it might be worth checking if there are any hardware issues specific to the affected users' devices.

 

Internet Connection: A weak or unreliable internet connection can cause jitter. Upgrading your internet connection or using a wired connection instead of Wi-Fi can help reduce jitter.

 

Packet Prioritization: If voice packets aren't prioritized, then the end user is very likely to experience jitter Implementing Quality of Service (QoS) settings that prioritize VoIP traffic can help reduce jitter.

 

Bandwidth Usage: High bandwidth usage can also cause jitter. Try to minimize the usage of bandwidth-intensive applications during VoIP calls.

 

If none of these solutions work, it might be worth reaching out to your VoIP provider or a network specialist for further assistance. They can help identify any specific issues with your network configuration or VoIP setup that might be causing the high jitter.

 

I also suggest you open a support case.

 

I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.

Please, if this post was useful, leave your kudos and mark it as solved.

on average about 20. The AP these two users connect to is our reception one so significantly less. When I was doing the tests I think our 3 laptops were the only clients.

The AP I am currently connected to on my own laptop is at 44 and my jitter is still averaging about 2 or 3ms.

I brought one of their laptops here and they still got 60ish, so their jitter is consistent regardless if there are 3 or 44 clients on the same AP.

PhilipDAth
Kind of a big deal
Kind of a big deal

Does the SSID have 2.4Ghz and 5Ghz enabled, and are they using the 2.4Ghz channel when they have the issue?

 

Have you checked that you are all associated with the same AP?  Perhaps they are using an AP much further away.  try checking out:

http://my.meraki.com/

Are you all connected to the same SSID, on the same band, and have similar signal strengths?  I suspect you'll find something not the same.

had no idea this tool existed! its mint 😄 

so I went and did more tests.

I used my laptop and a problem laptop.

We have the same OS, same version
Same wifi adaptor
Same wifi driver

Both connected to the same AP, 5Ghz.
Both have signal around -40dB

The channel utilization was 10% 

After lots and lots of speed tests on both laptops - the average down/up speed on both was 400 / 200 ish.

My ping was usually about 15 and the problem laptop was usually 30ish.

My jitter rarely went over 30ms - the problem laptop rarely went below 30ms.

Problem laptop often had jitter around 70 or 80
My laptop jitter never went over 50, and the 50 only happened once (it was mostly below 5).

Moving to a different area and different AP - same kind of result. The issue seems to follow the laptop around.




Adrian4
Head in the Cloud

cheers

PhilipDAth
Kind of a big deal
Kind of a big deal

I can tell you exactly what this problem is.

 

The WiFi power saving settings on the notebook.  Not all notebooks expose the WiFi power saving settings via the GUI - so you may need to update the settings via the CLI (see below).

The notebook with low latency will use CAM (constantly awake mode).  With PSM mode (power saving mode, it also goes by other names), the WiFi NIC powers down for a set period of ms, then powers up and asks the AP for all buffered packets, and then powers down again.  This reduces power consumption but increases latency.

 

Run these two commands, reboot, and it should be fixed.

powercfg /SETDCVALUEINDEX SCHEME_CURRENT 19cbb8fa-5279-450e-9fac-8a3d5fedd0c1 12bbebe6-58d6-4636-95bb-3217ef867c1a 0
powercfg /SETACVALUEINDEX SCHEME_CURRENT 19cbb8fa-5279-450e-9fac-8a3d5fedd0c1 12bbebe6-58d6-4636-95bb-3217ef867c1a 0

   

ah this is exactly the kind of thing i was looking for! I was going down the "it must be some software doing something weird" because it was very specific to just these two laptops. - I didn't think about the adaptor settings because the issue just randomly appeared one day 😄 (maybe an update changed them or something).

Ill go and have a look cheers 😄

PhilipDAth
Kind of a big deal
Kind of a big deal

The power saving mode can be affected by a lot of things such as battery level.  It normally shows up as an intermittent issue.

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