Solved

VoIP problems

Posted on 2009-05-05
7
582 Views
Last Modified: 2012-05-06
My network currently has 30 VoIP phones using 8x8. The network connection is Covad wireless 2MB up and down. Now I guess this is a dish on our roof. What the problem is clients in the office are getting dropped during calls and their phone will randomly display no service. I've checked the bandwidth and it looks like it's fine. Also the jitter looks fine. What should I look for when trying to diagnose this. Any tips?
0
Comment
Question by:thursdasy
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
  • 2
  • +1
7 Comments
 
LVL 22

Expert Comment

by:Syed Mutahir Ali
ID: 24310468
Hi,
What kind of routers are you using ? Have you tried any tools to monitor network traffic to see if their is a certain type of traffic which causes this ?
Also, consult with 8x8 to see if they have any newer firmware for their devices or any known issues like this ?
Mutahir
0
 
LVL 2

Author Comment

by:thursdasy
ID: 24310788
@mutahir, yes I've been talking with 8x8 support and they say everything is correct. I've also talked with Covad wireless and they say the connection looks fine. One thing I must note is that our phone network is half duplex. Is this bad? I'm attempting to switch it to full duplex.

And I haven't monitored the network traffic yet Ill be doing that tomorrow hopefully once I figure out how to do it with our new switch.

Thanks.
0
 
LVL 32

Expert Comment

by:harbor235
ID: 24314631


Good quality VOICE over an internet connection is not impossible however it is best effort. In addition, you are using a wireless conenction to Covad to boot. Latency and jitter are both key components when doing VOIP as well as QOS. Without any meaningful way to prioritize your voice traffic end to end you are at the mercy of the networks best efforts.

The alternative of course is to get a dedicated service or use an ISP that has VOIP services directly, that way you are not potentially routing over the Internet.

harbor235 ;}
0
Turn your laptop into a mobile console!

The CV211 Laptop USB Console Adapter provides a direct Laptop-to-Computer connection for fast and easy remote desktop access with no software to install.

 
LVL 22

Accepted Solution

by:
Syed Mutahir Ali earned 250 total points
ID: 24317899
Half duplex isn't going to help much but as I mentioned, unless you have some kind of traffic analysis you can't come upto a conclusion
On the physical aspect of the topology as Harbor has mentioned a wired connection (dedicated) would definitely be of good quality then what you have at present.
Did you had these problems before? Was it running on wireless and was fine and just recently started to give problems? did the number of phones grew ? Many questions and aspects to look at
 
0
 
LVL 2

Author Comment

by:thursdasy
ID: 24319585
@mutahir This is mostly my point what can I use for  traffic analysis? And what am I looking for? Do you have any text that covers this? Currently Im using VisualRoute to get an idea of what the ping time is between us and the VoIP carrier.


I have experience some problems in the past but never this bad. Also we recently got 10 more users. Every time I do a speed test on the network though we don't have any bandwidth problems. What I am seeing though is QOS reports are coming back with a low percent.

0
 
LVL 32

Expert Comment

by:harbor235
ID: 24321337


I did not see that , half duplex? Yes that is not good at all, i agree with mutahir.

harbor235 ;}
0
 
LVL 6

Assisted Solution

by:peter41
peter41 earned 250 total points
ID: 24324863
There are important two network parameters for good VoIP:
- low latency. Try to set ping from your network to your VoIP provider sever, for example "ping x.x.x.x -n 10000" and look at output. If responses are less than 70ms, it is fine, if times are more than 100ms, then it is commonly not suitable to use for VoIP. Maybe you will see some time intervals when ping responses will not be received at all... :-(

- sufficient bandwidth. It is depending on used voice codecs (type of compression), and this type determines needed bandwidth for voice streams. So check what codecs are used in your VoIP device. Personally I use in my VoIP router (Sipura) codec which needs about 180kbits (sum of both directions).
I am connected also through wireless connection from T-Mobile ISP, but there is used Flash-OFDM which has very good latency (comparable with cables) and thanks to this I can to use VoIP with their connection 1,8Mbit/512kbit. Sometimes (approx. once per month there is not good quality, but 99% calls it is OK and I can live with it. UMTS networks has not such good latency like Flash-OFDM technology, so investigate your wireless technology.  
0

Featured Post

Webinar: Deploying MySQL in production 6/22 11am

Join Percona’s Senior Operations Engineer, Daniel Kowalewski as he presents Deploying MySQL in production on Thursday, June 22, 2017 at 11:00 am PDT / 2:00 pm EDT (UTC-7).

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Outsource Your Fax Infrastructure to the Cloud (And come out looking like an IT Hero!) Relative to the many demands on today’s IT teams, spending capital, time and resources to maintain physical fax servers and infrastructure is not a high priority.
PRTG Network Monitor lets you monitor your bandwidth usage, so you know who is using up your bandwidth, and what they're using it for.
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
There's a multitude of different network monitoring solutions out there, and you're probably wondering what makes NetCrunch so special. It's completely agentless, but does let you create an agent, if you desire. It offers powerful scalability …

729 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question