Bad Call Quality

Modified on Tue, 31 Oct, 2023 at 5:06 AM

Noisy lines and call cuts

Call Quality issues

Area	Checklist/Guide
Jitter	1. Run a speed test: https://speed.cloudflare.com/ 2. Is the Jitter below 30ms? 3. Does the customer have enough bandwidth to support the number of devices connected? 4. Does the issue occur on only mobile/WiFi or on both? 5. Are you able to prioritize bandwidth via QoS? 6. Is the customer’s router fit for the connection they have?
Latency	1. Run a speed test: https://speed.cloudflare.com/ 2. Is the Ping below 20ms? 3. Does the customer have enough bandwidth to support the number of devices connected? 4. Check that the distance between the customer and the router is not too great. 5. Is the customer able to close or power off any devices and programs using background data? 6. Can the customer test WiFi vs Ethernet?
More checks	1. Restart the router if using WiFi only. 2. Test a different device if possible (the device may be faulty)

What causes call quality issues?

Jitter is one of the most common VoIP call quality problems. It usually occurs over connectionless or packet-switched networks. VoIP uses packets to send audio across a network, these packets can sometimes take a different path than intended and results in a call with poor quality or scrambled audio.

What to check?

Broadband connection: check that the customer has a stable connection. Running a speed test using the following link can provide information as well – https://speed.cloudflare.com/

NB: How much jitter is acceptable? For VoIP, jitter measures the variation between packet delays for voice communications. The metric for this is expressed in milliseconds, or one-hundredth of a second. Cisco recommends jitter on voice traffic should not exceed 30 milliseconds

For VoIP, you want your latency(ping) to be around 20 ms or less.

FUN FACT:

If you imagine the IP network is a road, VoIP jitter is essentially road congestion caused by too many cars. The technical definition of VoIP jitter is the variability over time of the network latency. Latency, in turn, is defined as the time taken for one packet of data to pass along its route.

Test the connection on both WiFi and Mobile Data to isolate the issue. This will help you better determine whether the call quality is being impacted by the network/connectivity.
Check the router settings to ensure that SIP ALG is disabled. You can also enable QoS to improve the quality of the VoIP calls (in most cases this will only be impactful if the customer has multiple devices connected to their router. If the customer only has 1 device connected, QoS will most likely have no impact)
Contact or check with the network provider to ensure that their connection supports VoIP.

In the event that you have done these checks and cannot identify any issues, this would need to be escalated to P2, they will be able to retrieve traces and do a more in detail check and decide if it should be escalated to Enreach or not.

Helpful link to send the customer:

https://bonline.elevio.help/en/articles/417-having-call-quality-issues