cancel
Showing results for 
Search instead for 
Did you mean: 

Jitter / Crack up

oakserver
Dabbler
Posts: 10
Registered: 30-07-2007

Jitter / Crack up

Hello,
Since I have been on the Voip trail I have not really been able to make very good quality calls, to the point where I just have to give up and call the person using a normal landline.
The call has considerable jitters and on occasions the call goes silent for a few seconds and then carries on. The person at the other end says my voice keeps cracking up too.
I have tried testyourvoip and got a score of 4.4 which isnt too bad. The results are as below:
http://www.testyourvoip.com/details.html?id=4R86X8
I have a Nokia N80 and the X-Lite program, and both methods have the same problem. I have a Linksys router WAG354G i think.
Has anybody else got these issues and know what I can do about them?
Thanks
21 REPLIES
mcgurka
Grafter
Posts: 764
Registered: 09-10-2007

Re: Jitter / Crack up

Ive had a few problems like this, and the crack-up of calls, and 'dead line' is usually caused by a lack of bandwidth, or high latency between your device (N80) and the voip server sip2.plus.net.
Could you try running a ping to the server by performing the following steps..
Click Start > Run > Type 'cmd' (no quotes) > click ok
A dos window should open, in here, type:
ping -l 4096 lilac.gradwell.net
and press enter. You should see 4 results, similar to the following..
Pinging lilac.gradwell.net with 4096 bytes of data..
Reply : Time = 53ms : Bytes = 4096 : TTL=52
Reply : Time = 53ms : Bytes = 4096 : TTL=52
Reply : Time = 62ms : Bytes = 4096 : TTL=52
Reply : Time = 61ms : Bytes = 4096 : TTL=52
Ping Complete!
Could you do this, and post a note of the times here, should let me see if you are seeing slow connectivity to the server.
Scott
<edit> Just had a look at your MOS results, and it seems you are seeing 100ms+ delays to the sip server, if you do the above, we can confirm / or not if this is the case</edit>
oakserver
Dabbler
Posts: 10
Registered: 30-07-2007

Re: Jitter / Crack up

Thanks for the reply. Here as my pings as you advised:
Reply from 193.111.200.56: bytes=4096 time=123ms TTL=57
Reply from 193.111.200.56: bytes=4096 time=121ms TTL=57
Reply from 193.111.200.56: bytes=4096 time=123ms TTL=57
Reply from 193.111.200.56: bytes=4096 time=119ms TTL=57
Does that look bad?
mcgurka
Grafter
Posts: 764
Registered: 09-10-2007

Re: Jitter / Crack up

Hmm, it most certainly explains the periods of silence in the calls.
I opted for a 4Kb packet, to better simulate the effects of voip traffic... I find that a little ping packet isnt up to the job!
Ok, my test *could* be a little harsh on the connection, so we can put it down to either latency at the server end, or at your end, can you run the test again, but this time as the following:
ping -l 1400 lilac.gradwell.net
We can then compare the set of your results, to the ones from here.
Scott
<results from here>
Reply from 193.111.200.56: bytes=1400 time=28ms TTL=52
Reply from 193.111.200.56: bytes=1400 time=30ms TTL=52
Reply from 193.111.200.56: bytes=1400 time=26ms TTL=52
Reply from 193.111.200.56: bytes=1400 time=27ms TTL=52
</results from here>
oakserver
Dabbler
Posts: 10
Registered: 30-07-2007

Re: Jitter / Crack up

Much better with a smaller packet but still not as good as yours.
Reply from 193.111.200.56: bytes=1400 time=53ms TTL=57
Reply from 193.111.200.56: bytes=1400 time=53ms TTL=57
Reply from 193.111.200.56: bytes=1400 time=55ms TTL=57
Reply from 193.111.200.56: bytes=1400 time=54ms TTL=57
Do you know how I can improve this? I have tried all sorts with no luck. Should I report it to plusnet support?
Thanks again for your help.
mcgurka
Grafter
Posts: 764
Registered: 09-10-2007

Re: Jitter / Crack up

there is a fair chance that removing interleaving from your line (if it isnt already) can drop up to 20ms off ping times.
The downside is, it may make your line sync at a slightly slower speed.
Can you check here http://usertools.plus.net/exchanges/ to see if your exchange capacity is red, amber or green? If its green, then I would give de-interleaving a try. (if you want to post your router stats, I could look and see if there will be a difference in speed)
Scott
oakserver
Dabbler
Posts: 10
Registered: 30-07-2007

Re: Jitter / Crack up

Hmmm.. Didnt reaslise turning interleaving on or off was an option but it sounds like hasstle and downtime??!!
My router stats are: (note this was following a reboot and probably the speed will drop to around 4500 Kbps later.)
DSL Status:  Up   
      DSL Modulation Mode:  GDMT   
      DSL Path Mode:  INTERLEAVED   
      Downstream Rate:  5344 Kbps   
      Upstream Rate:  448 Kbps   
      Downstream Margin:  4 db   
      Upstream Margin:  14 db   
      Downstream Line Attenuation:  44   
      Upstream Line Attenuation:  28   
      Downstream Transmit Power:  0   
      Upstream Transmit Power:  0   
           
PVC Connection
               
      Encapsulation:  RFC 2364 PPPoA   
      Multiplexing:  VC   
      QoS:  UBR   
      PCR Rate:  0   
      SCR Rate:  0   
      Autodetect:  Disable   
      VPI:  0     
      VCI:  38     
      Enable:  Yes   
      PVC Status:  Applied
mcgurka
Grafter
Posts: 764
Registered: 09-10-2007

Re: Jitter / Crack up

Not at all, its an overnight order. Your router will d/c (normally at around 4am) and then reconnect again right away.
Im not sure how the line will perform without I/L on, but ive asked one of the comms guys to let us know if there will be any likely impact.
Scott
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Re: Jitter / Crack up

I'd certainly have no issues trying to remove interleaving to see if it helps to fix this problem.
Give me a shout if you would like me to do this for you.
oakserver
Dabbler
Posts: 10
Registered: 30-07-2007

Re: Jitter / Crack up

Is it easy to revert if it caused any unexpected issues?
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Re: Jitter / Crack up

Very easy Smiley
We would just place an order to add interleaving which is also an overnight order.
oakserver
Dabbler
Posts: 10
Registered: 30-07-2007

Re: Jitter / Crack up

Ok yes please. If you could try and get interleaving removed on my line to try and help with ongoing VOIP issues that would be great.
Thanks
mcgurka
Grafter
Posts: 764
Registered: 09-10-2007

Re: Jitter / Crack up

Cheers James!
Best of luck, heres hoping it solves the problem, let me know how you get on!
Scott
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Re: Jitter / Crack up

Hi there,
I've placed the order now, which should complete tomorrow.
oakserver
Dabbler
Posts: 10
Registered: 30-07-2007

Re: Jitter / Crack up

Thanks very much.
Just one question, how do you know my plusnet username which is different to my alias?
Mike.