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What VoIP Is Actually Good For
gManZboy writes "One of the things that's bothered me about VoIP is that other than so-so quality phone service at a cheap price, what's the big deal? I mean so you can now deliver voice mail into e-mail because it's all IP packets, does that mean I should ditch my telecom investment. Well in part 3 of Queue's special report on VoIP (here's part 1, part 2) two authors from Bell Labs help explain actually useful things you might do. Now I get it."
I had a rather frustrating experience with the Net2Phone Voiceline product. Simply put, no matter how I tried to install it, it wouldn't give the green "provisioned" light or a dial tone.
Their tech support was less than useless at telling me what was wrong... they just processed the return instead.
Having used Vonage for several months I can say I am very pleased with their service and the quality of the calls. Before Vonage my only phone was a SprintPCS phone. When I got Vonage and called family/friends to tell them about a new number most of them commented how much clearer it was compared to the PCS phone I usually call them on.
;)
The only time I have had a 'problem' was when I was downloading some files on bittorrent AND playing FFXI Online and received a phone call. There was a slight echo audible on my end.
I have actually convinced my father and two friends to ditch the local phone company and get VOIP. They are also very pleased with the service and money they have saved, which equals free months of phone service for me!
-"so-so quality"
This is simply not true. Voice packets are given the highest priority across the network. If a voice packet does not make it to the destination, it is not resent. If the proper investment is made (you need newer switches and equipment) and the configuration is correct, it really does work great. I think it is ideal for an office with 30 people, especially if it is in a rural area where you may be paying a lot for a frame relay circuit or other connection. This setup can be done using Avaya VoIP phones in just a few hours and is very reliable!!
http://tomgould.com/
I don't have first hand knowledge of the actual testing that was done because I just transferred here. However, I was told by one of my professors that the school just tried to implement a VoIP system, but the sound quality was terrible. In fact, they've already dropped it and gone back to the regular PBX / POTS system.
under peak hours, the lag has got to suck...
Lag is an artifact of an poorly provisioned network. If you had end-to-end, trusted QoS, lag would never be noticable. Every important packet - voice, game, etc - would be delivered on time, and all the background "junk" - web, e-mail, BitTorrents - would fill the gaps between the important stuff that can't tolerate delay.
The trouble with VoIP is the dependence on QoS, which most third parties can't provide. I've been tempted to try Speakeasy Voice, since they should be capable of setting good QoS for the VoIP service. But I still haven't checked pricing to see if it would actually save me money over traditional phone & DSL.
I don't know how many phone calls you have ever made in your life, but my experiance tells me that they are definately NOT "... continuous constant bit rate data streams."
I tend to talk a bit, listen a bit, talk, listen back and forth, etc. And of course it is spoken word so there are pauses and other irregularities when I am talking.
Maybe there are resons it won't work, but yours is specious. Most likely the real problem will be getting all the switches/routers and other infrastructure, between you and the person you are talking to, to agree that your packets are indeed more important than all the current porn traffic and to expidite them.
However, I've had others swear by their VoIP. It seems to me that there is still just too many variables in the IP infrastructure for the experience of VoIP to be uniform. Not to mention the issues with power outages, 911 service, and the like.
Another thing to note is that having voice mail sent to email is not a feature of VoIP per sey. We are currently implementing an email system that has this ability, given that you have the right voice mail equipment. While there are some features that VoIP does offer that can't be done with POTS and appropiate equipment, many of the features being touted as "VoIP only" features can be done with POTS.
That said, about 5 years ago I was involved in a project to roll out VoIP in a new building (about 300 people, a call center of about 10 stations included). We used Cisco equipment and had two 24 channel trunks come in from POTS (one for local, one for long distance). Once it was up and running, the sound quality was nearly as good as POTS - we did have a slight echo once in a while, but other than that, it was great. We, of course, had complete control over the network, so doing QoS and stuff like that with voice packets was easy.
VoIP, if done right, can be nearly as good as POTS in terms of sound quality, if not better. But given all the variables (phone, DSL/Cable router, your ISP, the POTS/Internet interface, etc), there are just too many places that can cause quality to suffer. And the problem becomes worse if you try and use a fax machine over a VoIP line, which doesn't have a high tolerance for packet delay.
Skype seems to have taken VoIP a little further ahead by introducing a better compression and using a peer-to-peer network to distribute the voice packets. How they actually do it is still a well guarded secret currently. But it work behind firewalls (provided the firewall is open to HTTP or a proxy that support port 80). What amazes me is that within a good sizeable dsl line (768 down, 128 up) it can support 4 way conference quite well. I did a bandwidth measurement (using NetMeter) it only uses approx 4k to transfer both ways and the quality is like using your cellphone. I also used skypeout paid EURO20 just to try out. Quality is not bad to areas that have very good network infrastructure like the US, Asia, but got a bad quality in Russia. Possibly not enough users on the peer to peer network. The other thing I found is that the quality depends on the number of users on the network (obviously for a peer-to-peer network). In a normal day I have over 800k users and that allow pretty decent voice quality. However at 400k users, quality is bad sometimes can't even get connected. But the skype network is growing and like BitTorrent, the more popular it gets, the better it becomes... I am sure there are more people who has used Skype here at /.
-m-
Power outages are a problem, but the consequences can be minimized. I currently use Vonage through my cable modem. I have my cable modem, router and Vonage box on a UPS. As long as I turn off my computer shortly after a power outage, the UPS can give me a few hours of phone usage, and I could get a stronger UPS and/or dedicate a UPS solely for the cable modem/router/vonage. Of course, if the outage is widespread and the cable service is also affected, then I won't have phone service. Vonage does have a function that automatically forwards your calls to a number that you set if you lose your connection. I have this set to my cell number. I can always use my car to charge my cell phone if necessary, so I shouldn't miss any calls unless cell towers are out, which is pretty rare.
I mean so you can now deliver voice mail into e-mail because it's all IP packets, does that mean I should ditch my telecom investment?
Yes! http://www.freedomvoice.com
We're replacing our knackered commander system (15 years old) with a bunch of VOIP phones (Snom 190). Also we're splitting our shop into two premises; using a WiFi link (with WEP/MAC filtering/IPSec/L2LTP etc for security).
Using VOIP on our local LAN/WAN, we can share the same PSTN line pool (about 20 lines total) between both shops. If someone dials one shop but wants to speak to someone in the other, we can transfer that call. Very useful, not to mention the other possibilities with Asterisk (caller ID, call logging, stats, voicemail, extensions, music on hold, etc).
As for actually using a VOIP carrier for outgoing call... no, not yet.
We're setting up with Asterisk and Digium TDM400 cards with FXO modules.
Standard x86 servers, Linux, Asterisk, Digium and Snom phones add up to a LOT less than the integrated turnkey solution we were looking to get from Siemens.
actually, (speaking as a telco employee) you can encrypt conversations over POTS with the proper hardware.
(and have been able to for some time)
What will be nice about VOIP is now you can encrypt your calls through cheap or free software, negating the need to buy specialised crypto hardware.
Many telcos are using VoIP in parallel with their PSTN backbones, and this is ok - most users don't even notice this behind the scenes VoIP application.
It has been decades since phone companies actually switched a dedicated piece of copper for a voice call - they long ago realized that they could digitize the call and multiplex the packets over a high speed connection (digitizing at 64Kbps for a voice call, which is why all of the telecom standards such as DS0, DS1, DS3, and so on, are multiples of 64 - it's the number of uncompressed phone calls that the line can handle). What you may be referring to is the fact that up until recently most telcos ran the voice network on somewhat proprietary protocols and network infrastructures (i.e. ATM), but because of the cost benefit of IP many of them have switched to IP for their data networks, allowing them to use the same networks for data as well (although they QOS their own voice traffic so data never preempts a voice call).
Speech coding techniques used in VoIP are well tuned to human speech, for which it may still have poorer quality than ordinary phone lines in terms of signal-to-noise ratio, but sounds about the same quality to the human ear. When a modulated signal is fed into a speech coder, you get way poorer SNR than a telephone line, so the transfer rate you can achieve is generally much lower than the 33.6kbps achievable on a phone line, and definitely much less than the size of all these VoIP packets generated, so there is no point anyway.
Since there is skype for pocket pc it makes any pocket PC into a mobile phone.
What's more it is only useful when you are making outgoing calls or expecting an incomming one so there is not that annoying incoming cell phone buzz.
People will switch entirely to IP telephony and it will be free eventually, the hardware to implement it will become powerful enough.
What's bogging it down? No standards. Same as Webcams there simply is no way to get everyone onto one system except to get them to abandon their old system, something the telephone network never had to deal with.
I would like to recommend this guide/tutorial http://www.automated.it/guidetoasterisk.htm#_Toc49 248757
They also got an iso that you can run without isntalling any software, although you need an usb memory for configs.
With QOS you can specify "low latency" or "high throughput", but not both.
One place this gets interesting is when there are two links between the same two routers, one may be a 2mbit land connection, the other a multi-Gbit connection via three satellites. In this case, the router could be set up such that low latency packets go over the 2 mbit connection, with a ping of 10 ms, where the high througput packets go over the satellite link with 3 seconds ping time.
Now, changing your file sharing application to "high throughput" is not going to get you the file faster, unless it's under about half a megabyte. (2 mbit/s x 3 seconds = 6 mbits including headers, to make it easy, we'll round down to 4 mbits of data, or half a megabyte). As soon as your file gets bigger than that, the Gbit link will still win, as the amount of data transferred is much bigger.
It's just like the old "stationwaggon full of dat tapes" argument. High latency, but one hell of a througput.
i'm still trying to figure out what possesses people to work so much. QUIT YOUR JOB. i mean, are you married? have kids? because if it's just you, just stop working so hard (think office space, it worked for me). if you have kids, and can't take such risks (because eventually you do get laid off and unemployment wasn't available to me), take job with better hours even if it means a slightly lower* standard of living. parents are more important than new things. *no amount of money can properly replace my time. seriously, stop working so hard. you're making the rest of us look lazy. but even worse, no amount of money can bring back lost time -- money (and the drugs you buy with it) only help you not think about how important time is and how you've wasted it
Im a Canadian travellign in Ecuador...I{m in the capital now, Quito, and there are a ton of internet cafes in the backpacker district. They all have voip phones and charge 10 cents a minute to canada/us and most of europe. A real phone costs 25 cents a minute and the quality is on par.