VOIP Interference

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UrbanMyth

121 posts

Master Geek

#196164 21-May-2016 12:34

Ever since we changed over to VOIP, my partner has been 'reminding' me that occasionally on the phone, it sounds like there is some sort of interference. It sounds all alien-like, almost like the phone noise on The Matrix movie. Makes it impossible to hear the other person for a few minutes.

I have heard it a couple of times myself, both when using our phone, and when calling into our phone from work.

We are currently on naked broadband: supplier is 2Talk.

ADSL as we cannot get VDSL here.

VOIP is with 2Talk.

My network hardware currently consists of DrayTek Vigor DV130 Modem Router, which is connected to a TP-Link TL-WR1043ND (v2) Router running Gargoyle.

My phone is a Yealink W52P.

After being 'reminded' a few times, I decided it must be a VOIP thing, so was looking to change ISP's and go back to old style phone line. While on the phone setting up new account with Orcon, they said their phones were VOIP as well. Which got me to thinking, if everyone is going to VOIP, the technology is obviously stable within NZ, otherwise I am sure we would hear a lot more about this.

Which brings me back to possibly the core issue, modem/router configuration. Is there something I have missed? Or not added?

I read a while back that VOIP relies a lot on QOS set up in the router. Is this true? Anyone able to offer me any help with what my settings should be?

If the settings in my modem and router are ok, could it be a dodgy filter? Network cable?

According to the Chorus tech, our phones lines are fine and we are getting the correct speeds for the distance from the nearest exchange, so I doubt it is that.

I don't really want to change ISP unless I absolutely have to, but "the boss" is at wicks end with the phone, to the point she is using her cellphone.

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kornflake

409 posts

Ultimate Geek

#1556781 21-May-2016 12:52

Too little bandwidth at the times of poor voice quality, do you have a layer 3 switch to implement QoS on your side? Could always get a HSNS connection with a minimum CIR level for the phone connection but don't expect it to be cheaper than a PSTN line.

sbiddle

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#1556792 21-May-2016 13:09

VoIP requires on a good quality connection. If you're on ADSL and saturating your connection and don't have upstream QoS in place you will see issues.

Sideface

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#1556797 21-May-2016 13:21

UrbanMyth: <snip> According to the Chorus tech, our phones lines are fine and we are getting the correct speeds for the distance from the nearest exchange, so I doubt it is that. <snip>

sbiddle: VoIP requires on a good quality connection. If you're on ADSL and saturating your connection and don't have upstream QoS in place you will see issues.

@sbiddle is right. A slow ADSL connection will not support good quality VoIP.

What is your line distance from the exchange, and what are your "correct speeds"?

Can you give us your modem stats - particularly your downstream attenuation? This could give a good clue as to the nature of your problem.

Sideface

UrbanMyth

121 posts

Master Geek

#1556836 21-May-2016 15:41

Ok..

According to Chorus and Wises maps, we are 1.4km from the nearest cabinet, which is copper fed.

https://www.chorus.co.nz/broadband-checker reports we should be getting up to 12Mbps, and also says we are getting up to 12Mbps

The modem reports the following:

Mode: ADSL 2+ Annex A

Up speed: 1080000

Down Speed: 13264000

SNR Margin: 12

Loop Att.: 26

TX CRC err: 0

RX CRC err: 0

Also checked further into the settings of the firewall and found 'Call Filter: Enabled'

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#1556865 21-May-2016 16:29

UrbanMyth:

According to Chorus and Wises maps, we are 1.4km from the nearest cabinet, which is copper fed.

https://www.chorus.co.nz/broadband-checker reports we should be getting up to 12Mbps, and also says we are getting up to 12Mbps

The modem reports the following:

Mode: ADSL 2+ Annex A

Up speed: 1080000

Down Speed: 13264000

SNR Margin: 12

Loop Att.: 26

TX CRC err: 0

RX CRC err: 0

Also checked further into the settings of the firewall and found 'Call Filter: Enabled'

Your loop attenuation of 26db suggests that you have a line length of about 1.8km (line length is often significantly longer than "as the crow flies")

Certainly too long for VDSL.

Your speeds seem quite reasonable for the distance with ADSL2 technology.

Changing ISPs is probably not going to change your ADSL performance.

Sideface

chevrolux

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#1556925 21-May-2016 18:06

Have you got QoS enabled on your connection? For just a single home line just set it to 10% and that will reserve some bandwidth for voice.

Edit: should clarify, you set this in the 2talk portal. Doesn't require any router configuration.

kornflake

409 posts

Ultimate Geek

#1556934 21-May-2016 18:39

How exactly does the QoS work with 2talk, do they really tag the voice packets in the hope the customers end is configured correctly.

sbiddle

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#1556943 21-May-2016 19:02

chevrolux: Have you got QoS enabled on your connection? For just a single home line just set it to 10% and that will reserve some bandwidth for voice.

Edit: should clarify, you set this in the 2talk portal. Doesn't require any router configuration.

2talk can't control your upstream though - and they can only control downstream if you're using them as the ISP

UrbanMyth

121 posts

Master Geek

#1556978 21-May-2016 19:52

Have done the 3 speed tests with 2Talk, and set QOS at 10% up/10% down.

Hopefully this improves things.

kornflake

409 posts

Ultimate Geek

#1556985 21-May-2016 20:53

Who is your isp? As per steves post, it means jack if your voice and data are with different providers. You may get get a placebo effect however.

speed

234 posts

Master Geek

#1556992 21-May-2016 21:42

I agree with Chevrolux. Since 2talk is your ISP you should take advantage of their ability to queue your voice traffic in front of other data and reserve a portion of your inbound bandwidth for voice. Like sbiddle says, this doesn't help with your outgoing traffic (for that you need to do QoS on your router), but since your wifey has been complaining about the inbound quality rather than the people on the other end of the conversation complaining, the inbound QoS (effected at 2talk's end) it's where you should focus your primary efforts for a free fix.

Having said that, I'd almost lay money on this problem being related to the intermittent and inconsistent quality of DSL circuits. Just because your line is short or achieves a certain speed at a certain time doesn't mean it is good 100% of the time. It could absolutely still be experiencing intermittent packet loss due to interference (think welders or motors in properties that your line neighbours somewhere between you and the cabinet), crosstalk and other affects, and those sorts of micro-outage issues often go unnoticed on normal data traffic due to being masked by the effects of TCP. Looking at 2talk's smokeping monitoring graphs might help you investigate further.

But to be honest, it's almost magical that DSL even works at all it is such a crazy technology. I personally _never_ deploy VoIP over DSL due to the unreliable nature of it's characteristics (call me a pessimist) and consequently for me and all the deployments our company do, it's fibre or nothing. Sounds harsh, but we just haven't the time for dealing with all the issues that DSL brings (and yet here I am replying ;).

My opinion is that the only way you can be 100% guaranteed of voice quality that your Mrs will be happy with is to move back to a genuine PoTS service (from a real PoTS provider like Spark or Vodafone, not another VoIP service), or move to UFB if your location supports it. Otherwise you'll be chasing ghosts for ever. Sorry to be such a nay-sayer but that's just how I see it. I know DSL _can_ work reliably for VoIP (if you're lucky!), but often it just doesn't and in your case it sounds like you're one of those oftens :(

UrbanMyth

121 posts

Master Geek

#1557107 22-May-2016 08:28

I already have QOS set in the router - sorry, should have mentioned this in first post.

As per original post, my ISP is 2Talk.

What I did last night was to set QOS at 10% up and 10% down on the 2Talk site. I may at a later stage change Up to 'auto', but for now we will see how things go.

First comments from my partner are that she is very happy as she has been able to listen to voice messages now (I didn't realise it was that bad). I have asked her to keep me advised of any further issues.

Thanks all for your help .. hopefully this is resolved :)

sbiddle

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#1557116 22-May-2016 08:40

speed:

But to be honest, it's almost magical that DSL even works at all it is such a crazy technology. I personally _never_ deploy VoIP over DSL due to the unreliable nature of it's characteristics (call me a pessimist) and consequently for me and all the deployments our company do, it's fibre or nothing. Sounds harsh, but we just haven't the time for dealing with all the issues that DSL brings (and yet here I am replying ;).

My opinion is that the only way you can be 100% guaranteed of voice quality that your Mrs will be happy with is to move back to a genuine PoTS service (from a real PoTS provider like Spark or Vodafone, not another VoIP service), or move to UFB if your location supports it. Otherwise you'll be chasing ghosts for ever. Sorry to be such a nay-sayer but that's just how I see it. I know DSL _can_ work reliably for VoIP (if you're lucky!), but often it just doesn't and in your case it sounds like you're one of those oftens :(

It's very easy to guarantee voice quality over xDSL - just deploy EUBA with a CIR component such as EUBA192. The sole purpose of this product originally was going to be for Telecom's PSTN replacement project.

Fibre also doesn't guarantee voice quality unless you're on a HSNS connection where both ends of the connection are fully managed and queued or you're using the CIR component of a UFB connection and using appropriate 802.1p tagging and your voice service is with the internet provider as I can't imagine there will be any who will tag traffic from outside their own network.

UrbanMyth

121 posts

Master Geek

#1557118 22-May-2016 08:43

sbiddle:

It's very easy to guarantee voice quality over xDSL - just deploy EUBA with a CIR component such as EUBA192. The sole purpose of this product originally was going to be for Telecom's PSTN replacement project.

Is this what companies like 2Talk and Orcon deploy now?

sbiddle

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#1557131 22-May-2016 09:21

UrbanMyth:

sbiddle:

It's very easy to guarantee voice quality over xDSL - just deploy EUBA with a CIR component such as EUBA192. The sole purpose of this product originally was going to be for Telecom's PSTN replacement project.

Is this what companies like 2Talk and Orcon deploy now?

Not at cheap residential xDSL rates, no. From memory 192kbps CIR is $8 per month extra, so that would be unsustainable. That's more money than they're probably making off an unlimited connection now!

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