Requirements & Network Optimisations
IP Ranges & Firewall Rules
Telviva Mobile and Telviva One require your firewall to allow traffic to the following:
IP Blocks:
network 197.155.248.128/25
network 197.155.249.128/25
network 197.155.250.128/25
port 4433 (TCP/UDP)
port 3478 (TCP/UDP) Outbound direction
Port 5349 (TCP/UDP) Outbound direction
Ports 32800 - 39999 (UDP) Both directions
Routing
Timers should be open long enough. Your firewall should allow outgoing & incoming UDP to the public internet. We utilise Websocket connections so HTTPS / WebSocket / Secure RTP should be allowed.
Wifi
Local network conditions have the biggest impact on voice quality. Jitter, latency, and packet loss can be the biggest contributors to voice quality issues in any VoIP network.
Latency | The time it takes the RTP (media) packets to arrive at the destination | Causes media delivery delays, callers may speak over the top of each other. |
Packet loss | Packets that don't make it to the final destination | Causes gaps and cut-outs in media, callers may not hear the other side. |
Jitter | Packets that arrive at the destination out of order | Cause a ‘robotic’ distortion effect in media, or packet loss when overrunning the jitter buffer |
Latency
High latency can substantially degrade a caller's experience. While there will always be some latency between the codec algorithm, the jitter buffer, and network traversal, the goal is to keep this to a minimum. Callers typically start to notice the effect of latency once it breaches 250ms, and find latency above ~600ms to be nearly unusable. Here are some strategies to minimise latency on your network:
Some lower bandwidth fixed internet connections can often have higher latency. If possible, upgrade your internet connectivity.
Stick to high-bandwidth connections. Mobile networks such as LTE (mobile 4G Data) can often have high latency.
Packet Loss
Packet loss, most frequently jitter-induced packet loss, can make a big impact on your VoIP call quality. Wi-Fi can be particularly bad for creating jitter. Here are some strategies to minimise jitter on your network:
If you have addressed the above issues and continue to have jitter related impact on your voice quality, you may consider configuring your router with QoS rules to prioritise traffic on the above media UDP ports. Given the large range of UDP ports, you should only do this with prior consideration to what other traffic may be flowing in that port range.
Call Quality
By following this guide, you can significantly improve quality of service for the wireless voice applications and reduce or eliminate dropped calls, choppy speech, fuzzy speech, buzzing, echoing, long pauses, one-way audio, and issues while roaming between access points.
3 key metrics for voice quality:
Network MOS - The Network Mean Opinion Score (MOS) is the network’s impact on the listening quality of the VoIP conversation. The score ranges from 1 to 5, with 1 being the poorest quality and 5 being the highest quality.
Packet Loss Rate - The packet loss rate is the percent of packets that are lost during transmission.
Interarrival Jitter - Interarrival jitter measures the variation in arrival times of packets being received in milliseconds (ms).
Perform a pre-install RF survey for overlapping 5 GHz voice-quality coverage with -67 dB signal strength in all areas. (Use Wifi Analyzer App)
If possible, create a new SSID dedicated to your voice over IP devices.
Set Authentication type to 'Pre-shared key with WPA2'
Set WPA encryption mode to 'WPA2 only'
Enable '5 GHz band only'.
Enable 'Traffic shaping' on the SSID to prioritise all voice traffic.
SET THE NAT “UDP TIMEOUT" to 600 SECONDS
SIP 5060 UDP / TCP -
RTP 10000-20000 UDP - internal Network / UDP 65550 if Vibe goes via Firewall
(This is not best practice and Vibe should not traverse the customer F/W, rather have a separate connection to the router if possible)
Set DSCP to '46 (EF - Expedited Forwarding, Voice)' for RTP