Business line - VOIP issues

[SOSAGES]

Hello all,

i was wondering if anyone could point me in the right direction.

A buddy of mine had 10meg NTL business cable installed the other day but is having issues getting his VOIP working on it.
The web connection seems fine but anytime he talks on his VOIP the person on the other end just gets a broken up bit of garbled speech. The incommig voice is always clear.

I had a look at the network speeds seem fine and other web related funtions work fine - tried changing routers (tried 2 different models) but still no joy.
I know VOIP is unsupported by ntl business (something that is just stupid imo) but i would of thought a 10meg line would be enough to hold 1 voip call..especially as i know other people on the 10meg NTL service using voip day in day out without issues.

can anyone point me in the right direction? ntl just dont want to know due to "unsupported voip".... :)
thanks in advance.
if you need any info let me know.

[Kymmy]

It might help if you tell us which VoIP system they're using??

I though have used SKYPE for a few years with no problems on a VB business line (10Mb on ex-NTL)

[danlufan]

My first view of this would be that the problem is at the other end, rather than at the 10mb business end. However the VOIP system in place may help.

[Graham M]

Could well be latency issues, that or the outgoing codec is too high a bitrate, as has been stated it might be helpful if we knew what sort of VoIP system was in place

[Sephiroth]

I agree with Graham_M. You've only described the symptoms, but they fit the scenario of downstream being OK and upstream being congested. Business BB shares the domestic infrastructure.

The Codec bitrate is worth a look at too because a tweak at the expense of some quality would require less upstream bandwidth, it seems to me.

[Kymmy]

Upsteram bandwidth on 10Mb is 700Kb, normally more than enough for general web browsing at the same time as VoIP, I'm wondering if there isn't something else using bandwidth at the same time..

Can I suggest for testing use a SKYPE account with the echo test, it'll at least tell you if you still have problems without wasting call costs

[SOSAGES]

Hi,

Sorry :) as i said happy to provide info.

They are using a voip service provided by voipfone.co.uk
Previously used this on BT and i have also used this on my 50meg line at home and the other business i know with 10meg uses it.

The phones are SPA942's by linksys (cisco now) with latest firmware.
They are using G711u codec (i think this is default)

One issue i would say is..
when they had the line installed the modem kept the external IP (it was running in NAT mode) so we couldnt port forward or anything.
We called NTL to ask how to change this over to bride mode and they told us what to do (log into modem with admin details and change the mode)
they then told me i shouldnt of done this and that the guy who told me to do it was very naughty.
The router (a dlink 615) now has the external IP and port forwarding works fine but NTL said that we are running in an unsupported mode and if anything goes wrong we will be charged money.
I said so how do we get to be on bridging mode without causing any trouble and they said only option was for us to have a static IP at an extra £10 a month. We said ok lets do that then and they said they couldnt do that as the system was down (this went on for a week) they also said to change it from dynamic to static they needed someone at the site to connect the modem direct to a PC - i had assumed they could just send the command down the cable to the modem it seemed silly expecting onsite staff to run around for NTL especially if no one at the site has any IT knowledge...

so currently thats where we are.
still trying to get a static IP and hope that fixes our upload VOIP issues.
Its odd because i have an identical setup somewhere else and it works fine (same connection speed, same phone, same router, same providers)

[Graham M]

still trying to get a static IP and hope that fixes our upload VOIP issues

I'm not going to say it won't but it SHOULDN'T, I am running a Polycom SoundPoint IP300 on a residential connection behind a router with no port-forwarding with a dynamic (or Virgin's version anyhow) on 20MB (was on 10MB before) and has always been absolutely fine

[Kymmy]

Even if you got the static IP the mode would still be exactly how you've set it which is Bridged.. the only difference is that the IP would stay the same on reboot and/or if you ever changed the MAC you can claim back the original IP.. Not really worth the tenner a month (though it's weird as I'm ex-NTL and it was a single £10 set-up only for 5 IP's, is this a new thing or just ex-Telewest??)

Have you tried it purely on it's own (i.e.. not via the router) Yes I know you won;t have internet but will make an interesting test to see if the router is the cause... If that works OK then query the 5 IP option (not available on some packages I think) as that then will allow you to place the VoIP before the router via a switch/hub

[SOSAGES]

That was my thinking but i have been assured by NTL that me changing it over to bridge mode was not the right way to do things and that a static IP changes lots of other "stuff" that could be causing me issues. I did point out that i had the issues running it on NAT mode.
As for the router, i have tried various models the one they are currently using is my dlink 615 from home that i use fine with my SPA942 phone and provider..but have tried a few netgear routers as well.
I think im ex telewest, which is why they cant just give me a static ip.
seems a bit of a joke really as i said to them i woudl like to try 2 things to resolve my issues.
1. a static IP
2. upgrade to 20 meg

i was told doing either would start a new 18 month contract and that they couldnt just try it for a month (if it fixed the issue i said i would stick with it) i then said well upgrading to 20meg is probably the best option (more upload) but they said i couldnt have 20meg and a static ip it was one or other..
also i was told if i went for 20meg i couldnt downgrade back to 10 ever.
i sighed and died a little inside.

[Kymmy]

I stuck with 10Mb as there is no fixed IP option with 20Mb...

I'm out of the minimum term (was 24 months) but there's nothing else around here apart from ADSL MAX options (not even a LLU) so I'm biding my time until VMB get thier backsides into gear and start offering better services more in line with recent *cheaper* residential services

[SOSAGES]

Hi,
Sorry for the bump but things have not got any better after 6 months.
Now on the 20MB service since July and its very hard to hold 1 VOIP call regardless of the provider used.
Virgin give me the usual "VOIP not supported" line i tell them its a joke and uses very little bandwidth.

Replaced the router a few times and tried different voip phones and software voip solutions but all suffer from the same issue.
even remote desktoping into a PC at work has its issues sometimes.

http://www.speedtest.net/result/1042366245.png is a typical speed test but i must admit normally the upload is a little higher than that.

modem stats are:

Cable Modem Status
Item Status Comments
Acquire a Downstream Channel 586750000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI


Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 4
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : 3.5 dBmV
Downstream SNR : 35.3 dB

Cable Modem Upstream
Upstream Lock : Locked
Upstream Channel ID : 2
Upstream Frequency : 22200000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 41.5 dBmV
Upstream Mini-Slot Size : 2

Cable Modem Upstream Burst
Req
Init Maint
Per Maint
Short Data
Long Data

(1)
(3)
(4)
(5)
(6)


Modulation Type QPSK QPSK QPSK QPSK QPSK
Differential Encoding Off Off Off Off Off
Preamble Length 64 128 128 100 80
Preamble Value Offset 396 6 6 396 396
FEC Error Correction (T) 0 5 5 3 9
FEC Codeword Information Bytes (k) 16 34 34 78 232
Scrambler Seed 338 338 338 338 338
Maximum Burst Size 0 0 0 35 0
Guard Time Size 8 48 48 25 137
Last Codeword Length Fixed Fixed Fixed Short Short
Scrambler on/off On On On On On

Hope that helps :) perhaps someone has something we can try.
It would be handy to know if the logs are ok looking. I will try and capture logs from when the system is playing up but right now all seems fine but it is ten to 7 so perhaps the business network isnt busy.

[ccarmock]

Is the VoIP endpoint a physical IP phone or a 'softphone' on the PC. I have seen this type of behaviour due to a duplex mismatch. I woudl check that the router used is set to auto negotiate speed & duplex on it's ports and confirm that the pc and/or phone is also set to auto/auto for network speed & duplex.

Fixed at one and and auto/auto at the other will not work correctly.

The modem stats look OK, though SNR maybe a tad low on the downstream? The speedtest stats look very poor for a 20 Mb/s line, and should be reason enough to call support. Possibly congestion on that UBR port?

[CJNorfolk]

The line there is quite capable of supporting a number of concurrent voice calls.

have you had support for your VOIP provider as this seems more VOIP than network from the info present (and Im a VOIP person)

I suggest that you do a pingtest rather than a speedtest, and look at jitter and latency.

How many phones are there ?
How many concurrent calls do you make ?
Does this happen all the time or only sometimes ? is there other activity going on at the same time - ftp upload, mail sends etc

I have had 3 concurrent calls and miscellaneous other activity on a 448k upload line without probs, so its unlikely to be bandwidth issue

[Kymmy]

All speed tests will do is tell you if the connection from your modem to the speed test server is working, as VoIP might only use half of the same connections you dont know if there's issues with the final routing or even with the VoIP servers..

[SOSAGES]

Yes PING times are a little odd sometimes i often run a ping to google.com -t and get some high response times. Does anyone have a good latency testing website?

The phones are physical phones that work fine on my ntl home connection and the line breaks up with only one voip call going on (out of a max 4)

its strange but i will investigate.

[CJNorfolk]

www.pingtest.net

There is a link from www.speedtest.net

It offers a grading of your service as well.

[pip08456]

For continuous monitoring there's this (http://www.thinkbroadband.com/ping) from thinkbroadband.

[Zhadnost]

As an aside, what firmware are you running on the DIR-615, does it have QoS support built in?

[SOSAGES]

Router is running latest firmware (plus i have tried other routers)
I have tried QoS
here is a typical ping during a voip call - its the time outs that worry me.
Reply from 173.194.37.104: bytes=32 time=53ms TTL=55
Reply from 173.194.37.104: bytes=32 time=17ms TTL=54
Reply from 173.194.37.104: bytes=32 time=194ms TTL=55
Reply from 173.194.37.104: bytes=32 time=24ms TTL=55
Reply from 173.194.37.104: bytes=32 time=49ms TTL=55
Reply from 173.194.37.104: bytes=32 time=61ms TTL=55
Reply from 173.194.37.104: bytes=32 time=229ms TTL=55
Reply from 173.194.37.104: bytes=32 time=149ms TTL=54
Request timed out.
Reply from 173.194.37.104: bytes=32 time=70ms TTL=55
Request timed out.
Reply from 173.194.37.104: bytes=32 time=530ms TTL=55
Reply from 173.194.37.104: bytes=32 time=330ms TTL=54
Reply from 173.194.37.104: bytes=32 time=25ms TTL=55
Request timed out.
Reply from 173.194.37.104: bytes=32 time=56ms TTL=54
Reply from 173.194.37.104: bytes=32 time=238ms TTL=55
Reply from 173.194.37.104: bytes=32 time=62ms TTL=55
Request timed out.
Reply from 173.194.37.104: bytes=32 time=34ms TTL=55

i called about the slow speeds but was told there is nothing they can do.

[Zhadnost]

Those latencies and inconsistencies are pretty horrendous for VoIP, a dropped packet then a response half a second late will exhaust any well configured jitter buffer.

Does it look the same when you aren't in a call?

Does it look the same when you aren't using a router?

Does it improve if you plug your computer into the switch port on the back of the phone (If it has one).

[CJNorfolk]

Hi

the results for a tracert both to the VOIP server and www.bbc.co.uk would be useful as well as the information from a quality test like www.pingtest.net as I mentioned before.
Thanks