Understanding Voice Quality Issues with Max UC

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Most call quality issues with Max UC are over mobile clients when running over the cellular data network. But this is not the only type of network issue. In fact you Max UC desktop most likely is never connected via a cell network. So what is happening that I am experiencing poor voice quality.

Most Popular Voice Quality Trouble Report

Most voice quality issues with the MaX UC clients (mobile and desktop) are the Max UC Client (Near End caller) hears the typical (Far End) caller clearly. But the Far End caller hears a garbled voice of the Max UC client. This is caused from Jitter and not having enough upload bandwidth.

Another problem is the delayed response between both parties, causing caller to over talk the other. This caused from slow response time (ping times) .

Jitter and Upload Bandwidth

Technically speaking a phone conversation has two streams of voice your voice path and the other parties voice path. In the VoIP world these are called RTP streams. So you have the RTP stream #1 from point A to point Z and the RTP stream #2 from point Z to point A.

Speaking in terms of internet bandwidth and VoIP. The Max UC Client uses your home internet connection's upload bandwidth to send your voice(Stream #1 A - Z) to speak to the far end caller and use your home internet connection's upload bandwidth to hear (Stream #2 Z - A) the far end caller voice. So the crazy thing is that most residential internet connections are not symmetrical (10 up and 10 down) they are asymmetrical ( 1 up and 10 down). Cell phones data plans are also asymmetrical.

If you have two much jitter, then packets will arrive out of order and the will simply be dropped (your conversation "the RTP Streams" can not wait to be heard). If you don't have enough upload bandwidth this will cause retires and more jitter. More jitter means more packets getting dropped in your RTP Stream.

Below are two speedtest examples of a cell phone using the Speedtest Applicaton.

This test is using the cellphone data plan (cell tower)

Cell Phone Down and Up Cell Data example 1

This test is using my home internet connection via WiFi

Cell Phone Down and Up over WiFI example 2

So both my home internet and my cell data plan are asymmetrical and have much slower upload speed that the download speed. And also notice that the Jitter for my home connection is much less that the jitter of the cell connection. So when I am at home I make sure my cell phone is connected to WiFi and my Max UC will have much better voice quality because there is more upload bandwidth and much less jitter.

 Note:  CTS Telecom, Inc business internet connections can be both symetrical and asymmetrical but in either case 
        have upload speeds 10 Mbits or higher.

Overtalk and Ping Time Latency

Overtalk is simply one caller interrupting another caller. Remember the day of walkie takies "over". Ping times are measurements of the round trip delay. How fast it takes to fly from point A to point Z in the conversation. The reason this is A to Z is because in between these two point are the many internet routers that are making your connection. Good PING times are always 3 ms or less, and bad PING times are greater 150 ms start to cause issues.

Latency is measured in milliseconds (ms), which is thousandths of seconds. A latency of 20 ms is normal for VoIP calls; a latency of even 150 ms is barely noticeable and therefore acceptable. Any higher than that, however, and quality starts to diminish. At 300 ms or higher, latency becomes completely unacceptable.

 CTS Telecom, Inc Business internet/VoIP services strives to have a latency of less than 3 ms.

So Really What Can I Do

For the low bandwidth and high Jitter and slow Ping times all you can really do is purchase faster and better internet service. Not always a easy thing to do if you don't live in the right spot.

You see speedtest results on my home internet, it not considered high end even by the provider that is selling it to me. I have had very good results running a VPN connection to work, while running the Max UC desktop client and all the while my other family members are watching Youtube TV and using their iPhones. But I have also experience periods of terrible voice quality. And when I do I have discovered it is usually one of these 3 things.

  1. My ISP provided router needs to be rebooted.
  2. My firewall provided by me needs to rebooted. (less now since I upgraded to a better newer firewall)
  3. My security cameras are using all my upload bandwidth sending video / pictures to my cell phone or email accounts.
  4. My children are playing video games and or running speedtest and this is using all my upload bandwidth.

Finally WiFi issues cause more problems with MaX UC because you either have older clients (PC, tablets, phones) running older protocols or older WiFI routers and access points running older Wireles G, or N. Get a newer AC or WiFI 6 router, if our renting a Router from you ISP tell them you need a newer router. If you get a newer router your older laptops and phones still may causes you issues if they don't support the newer AC and WiFi 6 standards. In WiFi newer is better, you may need to purchase a newer USB WiFi adapter for your laptop or PC. If possible run a ethernet CAT 5 cable from your Desktop PC or Laptop to your network router, this will help you Max UC desktp be more stable on the network.