How reliable is IP telephony?

How reliable is IP telephony?

Summary: Have you ever heard a weird kind of hissing, crackling or popping noise when calling someone on an IP telephony line? How rare is the phenomenon these days?


Those with long memories will remember a period a few years back when corporate IP telephony was not exactly what you would call ... mature.

(Credit: Avaya)

The scenario would always play out the same way. With your normal analog desk phone, you would place a call to speak to someone in another organisation, normally one in the financial sector with more money to throw around on the latest technology than sense.

As your contact answered their phone, you would hear a weird kind of hissing, crackling or popping noise, maybe accompanied by strange delays in between the time they spoke into the mouthpiece and when the sound reached their ear.

"ARE YOU USING VOIP BY ANY CHANCE?" you would ask loudly into your end of the connection.


What had happened, of course, is that your contact's IT department had rolled out a new corporate IP telephony system, but without really testing the network connection and quality of service required to support it in the back end.

I can't say how often this happened to me, but it happened often enough, and I'm sure it has happened to most people at some point.

The thing is, however, that over the past several years it has stopped happening. Now, I never have problems making calls using IP telephony, whether it be to organisations like Westpac that I know employ the technology, or even from my consumer-grade home VoIP connection (I'm an iiNet customer).

There could be several things behind this fact.

Firstly, organisations could simply be throwing massive network resources behind their IP telephony connections to guarantee they never, ever have problems that would be noticeable by upper management.

Or, secondly, that quality of service and other technology at the heart of IP telephony solutions has become very mature over the past few years.

What's your IP telephony experience been like?

Topics: Unified Comms, Banking, Cisco, Networking

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  • IP Telephony

    My experience is about the same as yours, although I am not so tolerant of poor voice quality in call centres. I still encounter crappy connections and am suprised that some places do not fix these configuration issues.

    As the technology is now 15 years old you would hope that the technology is easier to implement, especially echo, jitter and prioritisation settings. It wasn't that long ago when dial tone was a "feature" for some vendors.

    My biggest beef with VoIP is that given the (vendor?) assumption of unlimited bandwidth (ie TCP/IP networks) why do we still use crappy compression algorithms? Surely high quality stereo would be better?

    It seems to me that analogue mobile voice set the bar (very low!) for voice quality and the industry is patting itself on the back for achieving this bar for VoIP.
  • Quality

    I agree with you about analogue mobile voice, Simon. Generally speaking, mobile phone audio is pretty bad. IP telephony has the potential to offer something much better, and we should be aiming towards that!
  • stereo?

    Surely you jest. I don't know about you, but I only speak with one mouth, so there's not much stereoscopic sound to be captured in the first place.

    A higher bit-rate would be nice, but bandwidth isn't actually unlimited, even on the LAN (despite what people think).

    Same issue for mobile telephony. The more bandwidth you give each subscriber, the fewer users each tower can handle simultaneously. In a country where towers are few and far between (and blackspots and dropouts all too common), hankering after a system that would need even more towers might need to be thought through a little more.

    The author has pointed out that VoIP these days is perfectly satisfactory. What is there to be gained by transmitting philharmonic orchestra quality sound down the line? After all, it's just voice. 8kHz works fine.
  • High Quality Codecs

    High quality codecs are available on some VOIP networks, ask your provider.

    I know ( work for ) one that will accept a variety of codecs, including the latest HD & Video Codecs on offer. The biggest issue here is the hardware and network at the customer end.

    if your truly after HD Codec support in a corporate quality Sip Trunking provider then contact me.
  • Quality

    I'm an IINET customer with ADSL2 in Melbourne, and my VoIP is of such poor quality I generally have to resort to the PSTN network so as to both be heard and to hear the other end.

    I think I've used VoIP three times, and each time I've had to call back on the land line
  • Quality (lack of)

    I concur with Anonymous. I'm an iinet Sydney VOIP user and as an early adopter have only experienced marginal quality improvement..

    Overseas calls fare worst and it's often a game of two-up whether I need to resort back to the old, but, bullet proof PSTN.

    Consumer grade VOIP still just doesn't cut it in the reliability stakes.
  • VoIP Call quality

    I have had experience with both residential grade and business grade VoIP. On the residential grade such as the above IINET , Engin and other basic services it is not what i would run a business on. Great for calling granny but not for business. VoIP business grade has a dedicated link not touching the internet. I have VoIP with all the cheap calls and great features but it is simply ISDN call quality every single call. You just cant run a business on the "get VoIP with our internet connection" if you want to be happy use a business grade VoIP supplier.. I use NETSIP and i am very happy and my phone bill went down by more than 50%..
  • VoIP Quality

    VoIP can achieve a range of quality.

    What is essential is to meet the customers needs and stay within budget.

    Also you need to remember that most terminations and origination onto/from GSM and PSTN networks are below the quality achieved by VoIP.

    So you have to ask yourself if the cost of having "internal only" HD calls worth the potential extra budget required?

    Suffice to say VoIP is now leaps and bounds ahead and that's thanks not only to improved technology, but more so due to choosing to work with the right companies.

    If you need guidance please send my company an email to
  • stereo

    Stereo would be great for conferencing but really, I meant that it should be high quality sound at a minimum. I do not understand why compression is used, the only delay would then be in the ADC, thus reducing jitter and echo issues. The voip proposition was toll bypass for the first 10 years of this technology and I think minimising bit rates was a primary focus to improve the ROI model, and this shows in how voip has matured.

    If bandwidth is still an issue then surely TDM/ATM vdi is a better proposition?

    I have installed and used a number of solutions over the years and I still can't shake the feeling that voip delivers more for the vendors than it does the customers. I am yet to see details of an installation that could not have been implemented faster and more cheaply utilising older technology.

    Collaboration and unified comms looks to be the "sweet spot" for voip, but only if business work practices can be significantly changed to suit. We have had video conferencing for longer than voip and it is still not prevelant in the business community today.
  • VOIP Call Quality

    I've been using consumer grade VoIP for the last 3 years and other than some issues from time to time relating to outages with either my ISP or VSP, my VoIP is rock solid. So much so that when we moved recently I got my Cable broadband put on and no telephone connection - 100% VoIP in and out.

    I don't miss paying the $20-$30 in line rental and for that I've increase my download allowance so I can use one of the better quality codecs like G.711 which has a 64kbps transmission rate rather than G.729 which has an 8kbps bitrate. With less/better compression comes higher quality VoIP.
  • Feedback on Telstra Landline

    I know nothing about IP Telephony, but i am having these symptoms on my PSTN Telephone line, and am informed by Telstra that it must be some thing in my 3 separately used telephone handsets, one of theirs, another wired, and one Radio Cordless, all
    plugged in independantly, and separately.
  • IP Telephony

    Renai, you are right in saying that IP Telephony technology has matured. Vendors and customers are a lot more prepared to deploy IPT in their environment. Vendors offer network assessment services ahead of IPT deployments, easy QoS configuration parameters and finally good monitoring tools that measure voice quality. Customers have assess to mature best practices deployment guides, several other reference deployments and checklists put together by experts, consultants and analysts in the industry. Organisations like St.George Bank and Suncorp have successfully deployed IPT and extended it to get business process benefits from the technology which is where the real value of IPT lies beyond basic dial tone.

    Just as users are warming up to VoIP and its maturity, my concern is that the new competition for IPT seems to be coming from software only vendors who have no telephony experience and require the phone to be running on a PC that is as reliable as its operating system
  • IP Telephony

    IP Telephony requires Qos and decent bandwidth. I have setup VoIP many times, and using G729 codecs and proper routers such as Draytek and Snapgear good voice quality can be obtained.

    Most problems I find are caused by cheap routers/Modems (<$100) that claim to support QoS, poor network design, and codecs such as G711 being used on services with poor upload capability.
  • concerns

    I find it interesting that you voice the same concerns as the tdm voice guys back in 2000, when voip was being flogged by all the routing vendors. Back when Cisco called dialtone a "feature" ... history repeats itself..
  • good and bad experiences

    I use iiNet VOIP instead of a normal phone. I would say its 90% of PSTN quality but I am happy to wear that given the money it saves me on national/international calls vs convenience (against calling cards for example). Also, I have worked for at least 2 government clients with VOIP rollouts that have perfect quality calls.

    As far as shared bandwidth VOIP such as skype though, I cant see how anyone can take them seriously as a normal phone replacement. My experience with those has been terrible but some people swear by them.
  • No Problems Here

    Living in a semi-rural area of the Mid North Coast
    I find my voip service provides superior voice quality to my regular landline.
    Am on ADSL1 with Dodo & using the Mynetfone voip service with excellent results.
  • Peter T.

    I've been using Engin for a couple of years (using a phone plugged directly into an Egnin 3 modem) and I remain quite impressed with their VoIP. I started with a 512k/512k ADSL connection, moved to an 8Meg/256k connection and I am now on an ADSL 2+ connection. I've always found the quality and service to be very good. Before Engin, I tried a couple of soft-phones, but the quality was extremely poor.
  • MNF and TPG - VoIP is 100%

    1/ Mynetfone have a great VoIP product.
    2/ The TPG DSLAM respects the prioritisation given to the packets even from MNF.
    3/ My Draytek router works a charm.

    Bring these three aspects together the end result is faultless VoIP even during maxed out torrent download/uploads.

    Sure there’s always packet loss in the Internet and in the ISP back-haul, but it’s the respecting of QoS between the DSLAM and the home modem that matters. Without it VoIP is unworkable.

    It’s because TPG respect QoS from another Voice Service Provider (VSP) that I haven’t churned, even though they are infuriatingly bad at admitting when half their network is down (both call centre and service status page).