Deployment problems manifest themselves with quality of voice issues.    Technical articles which offer advice on solving VoIP voice quality problems discuss jitter, latency and MOS scores.  You do not have to become a VoIP nerd to make a phone call.  This article shares the most common deployment issues that cause jitter, latency and poor MOS scores without ever discussing them.

Symptoms of mild voice quality problems consist of robotic, distorted or slightly choppy voice.  In most cases, all the words can still be understood.  Moderate problems are occasional broken words which have to be repeated.  Severe problems include frequently distorted and choppy voice, lost sentences and dropped phone calls.  If you are experiencing any of the problems, here is a short list of common causes:

1. Voice Prioritization.  Most Internet connections are though DSL or Cable.  These connections typically offer more bandwidth from the Internet (download) than to it (upload).  Because the upload speed is smaller, voice packets usually need to be prioritized going out to the Internet.  If you can hear the outside caller just fine but they have trouble hearing you, than this may be the problem.

Voice prioritization MUST be enforced between the cable or DSL modem and your LAN.  More and more routers include this ability and it is becoming easier for the average user to set-up, however, a VoIP professional may still be needed.

Any use of a DSL or cable modem integrated WiFi access point is likely bypassing your voice prioritization.  Further, you may experience Internet problems just by having your WiFi radio active in your modem when using your microwave or cordless telephone.  It is strongly recommended that you disable this feature in modems and use a separate WiFi access point whose traffic must pass through voice prioritization to get to the Internet.

2.  Poor Service from Internet Service Provider (ISP).  VoIP is very sensitive to problems in the Internet and many ISPs do not take care that they provide a reliable circuit.  ISP networks are comprised of many routers frequently called hops.  Each hop has a potential for network congestion which may be fine for normal data traffic but will cause problems for VoIP.

Other causes of poor ISP service are faulty DSL or cable modem, old outside cabling that has become susceptible to weather and router problems within ISP network.  Further, DSL service may be degraded by frequency interference in the providers cable bundle, load coils and bridge taps.

Unfortunately, if you suspect poor service from your ISP, you need to test a different ISP, get a professional’s help or make use of a diagnostic tool.  I discuss a tool that you can use to inspect your ISPs network and pinpoint the exact location of a problem at the end of this article in my bio.

3.  Hubs and Ethernet Switches. Ethernet switches and hubs are the boxes that all of your data cabling connects to tie your computer devices together.  Your LAN cannot contain any hubs.  Instead Ethernet switches must be used, 100BaseT minimum.

4.  Multiple Chained Ethernet Switches.  Homes and offices with older wiring may use multiple Ethernet switches at desks, rooms and blocks of cubes to share single wiring drops back to the main LAN Ethernet switch.  Passing VoIP through multiple Ethernet switches to reach the Internet can cause problems.  Find ways to eliminate these extra devices through wireless access points and additional cabling.

5.  Insufficient Bandwidth for Number of VoIP Calls.  Without going into the dirty details of voice compression and codecs, you should in general have about 60kbps of upload bandwidth for every simultaneous voice call.  Insufficient bandwidth will choke your voice packets.

6.  Poor Wiring Inside Building before Cable or DSL Modem.  For DSL, each building or home has a DMARC (characterized by a wire block with orange cover) or Network Interface Box (homes).  The line carrying the DSL circuit should go straight from the DMARC to DSL filter and then DSL modem.  No other devices or connections should be in between.  Cable modems must work off of the primary splitter (not go through multiple splitters) and should be the leg with the highest decibel level.  When your cable repairman visits, he can verify.

7.  Other Applications May Prioritize Their Packets.  Any application can choose to use prioritization flags in their packets.  These applications may be in use with or without the network administrator’s knowledge including video and the myriad of consumer voice services such as Skype, Vonage, IMs, etc.  Assuming the use of these services is approved, your voice prioritization programming and Internet bandwidth needs to account for the extra bandwidth consumption.

These are 7 of the most common problems that may cause jitter, latency, poor MOS scores or just bad voice quality.  In some instances, you will need professionals to help with proper programming and problem detection.  Many tools exist as well.  If you believe all inside your house or building is in good shape, determining whether the problem is caused by your ISP can be difficult.

My website will make available a tool to check out your Internet connection in August of 2010.  Subscribe to my blog to be alerted of our new tool’s availability as it will deliver important knowledge and statistics when diagnosing Internet problems or dealing with your ISP.  It is free to use and nothing like it exists on the Internet today.  www.HostMyCalls.com

A:  Hosted VoIP/Hosted PBX service provides advanced telephone system features as a service over the Internet.  Many advanced features are uneconomical to include as part of a traditional telephone system.  Hosted service providers host the costly central equipment of the telephone system on their premise and use the same equipment for many of their customers. By hosting equipment, advanced features are delivered for a fraction of the normal cost.  Businesses no longer need to invest in the expensive central equipment of a telephone system.  In most cases, only phones will need to be purchased or leased.

Q:  What are the advantages of Hosted VoIP/Hosted PBX service?

A:  Hosted VoIP/Hosted PBX services offer many financial, operational and service advantages.  Financial advantages include lower capital expense, monthly payments are expensed instead of depreciated (phone system lease), more predictable and lower monthly recurring bills, easier and less expensive to expand, reduced maintenance and repair costs and scaled down office space from sending employees to work from home.

Beyond financial advantages, operational advantages boast improved call capacity, sending and receiving multiple faxes at a time, effortlessly distributing faxes, Automatic Call Distribution (ACD) for handling calls, easy telecommuter set-up and private and departmental telephone numbers.  Service advantages add quicker service response and diagnostics, 24 hour a day monitoring, easy disaster recovery and Mobile PBX.

Q:  Why is it so inexpensive?  What’s the catch?

A:  With many quality Hosted PBX/Hosted VoIP providers, there is no catch.  Delivering telephony services within the hosted model is simply more efficient and affordable than purchasing telephone system hardware and paying monthly for telephone lines.  Be wary of hosted plans that charge per minute for local and domestic long distance calls.  These plans can charge unpredictable, exorbitant usage charges on their monthly bills.

Q:  What are the common problems?

A:  The most common problem of Hosted VoIP users is their Internet connection.  The Internet connection must be large enough to handle the highest number of simultaneous calls and must be stable.  Read my article “Will Your Internet Connection Destroy Your VoIP Service” for more information.

Another common problem is occasional long delays in porting numbers.  If the porting paperwork is filled out incorrectly, delays can result.  In most cases, your old carrier and not your new Hosted VoIP provider cause the delays.  There are workarounds to porting delays such as call forwarding.  Your service provider should be able to help you.

One final common problem is loss of common features.  Although Hosted PBX services offer many new powerful features, some services lack common features that are taken for granted with smaller phone systems.  Busy Lamp Field (BLF), paging and off hook voice announce are examples of a few features that may not be offered by certain Hosted VoIP providers.  Before you select your provider, survey for the most common features used and make sure your provider delivers those capabilities.

Q:  What kind of Internet do I need?

A:  Your Internet connection can be DSL, cable modem, fixed broadband or wireless.  The type of Internet is less important than the size and stability of the circuit.  Click the link Four Steps to Determine Whether Your Internet Connection is Ready for VoIP.

Q:  If my Internet is down, are my phones down?

A:  If your Internet is down, all the phones behind that Internet connection will be down as well.  But it does not mean that you cannot receive your phone calls.  Your Hosted VoIP automated attendants and voicemails will still be functioning.  Some Hosted PBX services can automatically re-route calls in the event of an Internet failure to your other phones that may be using a different Internet connection or to other 10 digit telephone numbers such a cell phones.  Some advanced VoIP providers can shift calls to back-up or secondary Internet connections as well.

Q:  How easy is it to relocate the service?

A:  For most Hosted VoIP providers, moving the service may be as easy as plugging the phones into the LAN at a new location.  If the service provider has installed any routing equipment, then that may require some additional programming.  Regardless, when compared to moving a traditional telephone system, Hosted VoIP services are extremely easy to move and much less costly.

Q:  Can I take my phone home with me or on the road?

A:  If the Hosted VoIP service works over the Internet and does not require a VPN connection, then the answer is usually ‘Yes.’

Q:  What will the voice quality be like?

A:  Excellent assuming the following:

1.  The Internet bandwidth is sufficient to support the maximum number of simultaneous calls required.  You can check for this by reading “Four Steps to Determine Whether Your Internet Connection is Ready for VoIP” linked above.

2.  Voice packets are correctly prioritized going out to the Internet.  (Your provider may have to manage voice prioritization for you.)

3.  The Internet connection is stable.

Most WiFi enabled access points operate in the 2.4 Ghz frequency range.  This unlicensed frequency range is also shared by many common household and business devices such as cordless telephones and microwave ovens.  Use of these devices within range of your wireless enabled ISP router can cause interference and other negative effects ranging from seemingly insignificant brief Internet outages up to the need for router resets.  Internet outages lasting only several milliseconds will be disruptive to VoIP calls using a Hosted PBX or Hosted VoIP provider.

If your ISP router is equipped for wireless networking service and is not being used on your network, I recommend the wireless feature be turned off.  Turning the wireless feature off eliminates the negative effects of any interference and a potential security risk to your network.

If your ISP router is equipped for wireless networking service and is in use on your network, it could be a source of negative voice quality issues as it bypasses the necessary quality of service (QOS) management for voice traffic.  Migrating wireless network devices to a separate wireless access controller is recommended.  Further, when you use a separate wireless access controller from your ISP router, interference from other devices in the same frequency range will have no effect on the operation of your Internet router.

For more information on how you can insure the best possible VoIP call quality from your Hosted PBX or Hosted VoIP providers, please read my other blog articles.  Please let me know your thoughts in the comments section below.