01-23-2017 06:01 PM - last edited on 01-24-2017 07:21 AM by Julia_R
I have IPT/VOIP experience and have a specific question.... I have a TWC phone (xxx-xxx-3193) and a 3rd party VOIP phone (third-party is called RingCentral).... There is something I noticed and would like help understanding... When I use my third-party VOIP phone when there is no traffic on my Internet link the quality is just fine... When I tried to download a large file the voice is very choppy....
Now if I do the same test with the TWC VOIP phone during the large file transfer quality of the call is just fine.....
In other words it appears the TWC phone is getting some type of QOS.... Make you be able to explain this...or comment?
01-23-2017 06:29 PM
The phone line does receive a dedicated connection to us. It's not necessarily QOS, but almost like a secondary modem connected that is only used for phone service.
What you are reporting with the third party VoIP does sound normal, but you may be able to adjust your own QOS. That being said, it is not something we directly support.
01-23-2017 08:10 PM
Sorry, it doesn't work that way..
The TWC emta modem has a seperate mac address and is treated like a seperate modem, there is no QOS on it. IT is not affected (supposedly) by any data traffic on the router side.
Your voip connection however uses shared internet packets on your paid for internet connection with your data computer. The data/internet computer needs to have a qos restriction slapped on it so that it doesn't use all available bandwidth.
The problem is if you pay for 15 megs and qos restrict it to 12 megs, there's 3 megs available for the voip which is way more than enough.. But, if the TWC connection drops to 12 megs, there no longer is enough available bandwidth.
The problem gets much worst if wireless connections are in use.
It is a huge issue if IPv6 is in use by the computer and IPv4 is in use by the VOIP device. TWC speeds/ bandwidth fall drasticly with both in use ass they have to be sent sequentially not simultaneously.
01-23-2017 08:35 PM
01-23-2017 09:45 PM
That is only true on a single channel docsis 2 modem and running 20 meg speeds.
All of the docsis 3 modems have plenty of headroom for the fraction of a meg bandwidth needed for an emta phone IP.
01-24-2017 03:58 AM
ok thanks for the response....would you agree that it sounds liike the TWC has a dedicated VLAN for the voice traffic?.....at leaset thats what it sounds like to me
01-24-2017 04:21 AM
Well the biggest difference is that TWC isn't technically VOIP. It's Digital phone.
I know, I know. Petty distinction, but it does make a difference in this particular instance. Specifically, because the Digital Phone from TWC comes through a dedicated mac (and IP address) to your modem, it takes (virtually) no bandwidth from your ethernet connection (which, in turn, has its own mac and IP addresses). Since it has its own dedicated signal, so long as the modem is getting a strong enough signal, your internet and phone services won't compete for connection.
Of course there are a lot more details than that, and the article I've linked here goes further into detail, but that is about the gist of it.
01-24-2017 04:38 AM
thanks for the quick response...great article too.....ok last question...is the voice call packetized once it leaves the modem in my house?
01-24-2017 04:45 AM
It is, but with the TWC Digital service, it is done so over what is essentially a private line. With the TWC service, your analog phone (typical phone cable) converts to a digital signal and then moves that information down the allocated bandwidth. Because the digital line is dedicated, there is less compression, and packets aren't going to be impeded by other devices hogging bandwidth.
01-24-2017 08:48 AM - edited 01-24-2017 08:49 AM
It's also routed thru a lot fewer hops and servers to get to TWC's phone "switch"
Might be right at hop3 or on a Vlan from there to some regional switch...