About Us Contact US Where to Buy Voice packets are sent every 20 milliseconds and for good quality they need to all get delivered (low packet loss), in a steady stream without a lot of delay (low latency), and without a lot of change in the delay (low jitter). That is all very easy to do if the link is being used for voice only and the bandwidth is sufficient. If the link is being used for both voice and data, it requires the routers to give absolute priority to the voice packets and increases the bandwidth requirements. The voice should not exceed about one third of the bandwidth on a voice and data link. See this document for a discussion on The voice stream from the user is controlled by the user's router and the voice stream to the remote user is controlled by the Internet Service Provider. FacetPhone marks all of the voice packets "Expedited Forwarding" which is normal for VoIP. The priority byte is set to 0xB8. There are two ways of interpreting that byte. DSCP uses the high 6 bits so the DSCP field part of 0xB8 is 0x2E or 46 decimal. The older TOS shows this as critical precedence, low delay, and high throughput. The user's router needs to give those packets absolute priority. It also needs to not send more packets than the upload speed of the link because that will cause buffering and/or packet dropping in the DSL modem. If your hardware equipment is Cisco based, see this                                                     document for detailed configuration information on QoS. If the voice stream to the remote user is questionable, you can check with the ISP about adding QoS to the link. Otherwise a separate line is recommended so that voice can be completely separated from data. If your connection has a voice/data combination link and you are experiencing problems: 1. Which direction has the terrible audio? •   To the remote user. •   From the remote user. •   Both. (actually this is rare) 2. What is the DSL speed? •   Download. •   Upload. This site provides a good test to measure your bandwidth:   3. Is the remote user doing a lot of data activity while on the phone, such as a terminal server connection to look things up on a database, or to record info from the caller? 4. Is the remote user recording their calls? 5. Anything you can tell us about the setup would be helpful. User names and extensions. Time of calls that were bad. Voice Quality Issues for Remote Users with DSL Was this information helpful? We appreciate your feedback: