If you are experiencing call quality issues with Horizon, we would recommend that you complete the following checks in this order.
Codecs #
If you’re experiencing call quality/media issues the first check that you should do is check the codec and your customer’s access bandwidth.
G711 | High quality codec | 100kb per second |
G722 | Highest quality codec (“HD codec”) | 60kb per second |
G729 | Lowest quality codec | 40kb per second |
Use the above table and the below calculation to see if you have enough bandwidth for your customer’s Horizon Company.
Concurrent calls x Codec kbps = bandwidth required
Access #
The next thing you should check after the code is your customer’s access (i.e. the Broadband or Ethernet connection). The following items are key to check:
- Packet Loss
- Jitter
- Latency
If you are using Gamma Access then see the following Knowledge Base sections to help with identifying these issues:
Bypass the switch #
You should also try and bypass the switch to make sure that it is not the switch causing issues. Do this by plugging a handset directly into the router. If the call quality/media issues stop, you know the problem is with the switch.
SIP ALG #
All Horizon sites should have SIP ALG disabled.
I have checked all of the above #
If you have done all the above checks and are still experiencing issues you should report the fault to the Service Desk using the details in the Customer Service Plan on the Gamma Portal (Help and Support, Support Documentation).
The Service Desk will need a minimum of three call examples with the following details:
- Date and time of call
- Calling number
- Destination number
- Handset make/model
- Description of what has happened on that call
It is also helpful to let the Service Desk know the outcome of the access investigation and codec details.
