Is VOIP Over WLAN DOA?
prostoalex writes "Voice-over-IP in Wireless LAN environment - a futurist's dream of always-on always-connected service. Guy Kewney from eWeek tests the technologies that try to satisfy this market today and finds nothing but disappointment. " The best result we got was that just once, I heard his voice with a delay of about 15 seconds, saying "You just have to speak up!"--which was part of a 20-second burst of speech from him. The rest was lost.""
Well i have used stantaphone over my home wifi worked ok (1-1.5 sec delay) normal for anything of that nature.
VOIP over WLAN is not DOA. If you tweak the QOS etc settings and don't just throw things together haphazardly, then it works beautifully. Personally, I just wire VOIP to a cordless phone, then let the phone handle the wireless part. Enough of the ____ is dead articles.
I hate sigs.
First off, it's eWeek for crying out loud! Second, it's still too early to proclaim VOIP over anything (WiFi or Ethernet or whatever) dead. Second, I have seen it work and it worked wonderfully. Declaring VOIP over WiFi dead is like saying Apple's dead because it does nto have the market share that Dell does.
Gorkman
I couldn't accept incoming calls, I kept getting a busy signal, but I got my email (the article writer didn't) and even made a few calls. Quality was fairly good, and there was only a delay of a a second or so.
802.11 standard was modeled around having a CSMA/A algorithm that tried to be as much like Ethernet as possible. There is no provision in the BASIC standard to provide for clients to shut up for higher priority voice clients at all! This means that a data client can blow the voice guy to kingdom come.
There are extensions to the 802.11 standard like 802.11e and WME that will allow priority queuing and some minimalistic scheduling to take place. Other companies play tricks with the protocol to allow for voice clients to perform better under the BASIC standard but there are drawbacks.
In the end, it is too early to judge VOIP over WLAN because clients and access points have yet to adopt extensions to the basic standard.
-Ho
A collegue of mine has VPN over DSL to a corporate network. They do all their phones via VOIP. If you send him a ~1MB email while he's on the phone, the call goes down the toilet. Not exactly a "new millenium experience".
Engineering is the art of compromise.
VOIP over WLAN is DOA? WTF? I'm going back to DTMF over POTS ASAP!
In Soviet Rush, today's Tom Sawyer gets high on you.
...just use a phone?
Dear aunt, let's set so double the killer delete select all
I know a guy that just had problems getting KDE to work with his video drivers. Does that mean I can submit a story titled 'Is Linux dead?' and see it published on Slashdot?
I'd like to visit the magical world the submitter lives in where every new technology works perfectly from the get-go and never needs to improve and be developed. Must be nice.
Are acronyms overused, or is Slashdot focusing on making their posts palatable for SMS capable phones?
ShortFormBlog: Writing a little. Saying a lot.
At work i use my Cisco 7920 wireless VoIP phone. We are in the middle of a remodle of the IT department and it works great. I've had very few issues.
I'm a cucumber
... what would have happened if during the invention of the telephone, they all became put off and declared "Voice over Wires DOA" just because the 2nd test wasn't perfect.
It's not like this is as good as it's every going to get. If that was true, EVERYTHING would suck.
Slashdot sucks
VOIP/WLAN isn't DOA, but it might be MIA. OTOH CSCO, NT and LU have put a lot of money in IP that might result in BFD if they can improve their QOS ASAP. AFAIK, CSCO's VOIP/WLAN might present legal troubles although IANAL. But WTF, IYKWIM.
Me? I use Zalman headphones with a logitec webcam microphone duct taped on the right side. But I just use it for gaming. If I had to communicate anything other than "Our base is 0wn3d!" I would probably get something better.
Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
Someone needs to implement this in PHP. Then we'd get some real performance.
75% of my day is surrounded by WiFi access, however, that access is not always free (Tmobile, Leap Auth., Hotel services). I think that the problem with VOIP via WiFi is just that - not all WiFi is free. If we had free WiFi everywhere, then carrying a small VOIP would be cost effective, but would I throw away my cell phone? No. What if I broke-down on the side of the road? VOIP WiFi has no regard for those "emergency" situations. However, I would definitely get rid of my current VOIP "land line" and buy a WiFi model that I could take with me instead.
On another note, Im trying to get some users to a new website I created. It is basically my "day trading" stock journal online. Everything is free of course, so if you like stocks, I recommend taking a look. GroupShares.com.
Thanks,
Aj
-------
artlu.net
Is it just me, or am I the only one who ever thought this was completely stupid? Some company came to where I work and had a big presentation on VOIP over wireless... I thought it was ridiculous.
Let's see... you take your voice, turn it into packets to be reassembled a short distance away (espcially indoors). Ummm this has been around for millions of years... voices going "wirelessly" over the air... it's called "yelling".
FLR
My main phone line comes over a 6.1 mile 802.11b link. I use Asterisk PBX with the IAX protocol to bridge the calls.
And my Grandstream SIP phone works great attached to a Linksys WET-11 client bridge.
And my Ipaq runs IAXComm just fine over it's wireless card to use as a netphone.
Does the battery life suck... yes... does it work and show promise... YES!
Just because people have problems with these cheap (as in quality)(usually SIP or H.323 based) piece of crud phones doesn't mean the technology and possibilities are not still there. SIP is VERY prone to problems from NAT (which many wireless networks use of course).
Anyways... for my 2 cents though I say... just give it time.
Telcos have alot of dark fibre in the States. Most people assume that's optical fibre...but it's actually moral fibre.
What, is this supposed to be hard or something?
I've used iChat AV with Airport extreme (802.11g). There can be a bit of latency, but the audio is fine.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Of course, the new technology will have glitches. I may just be lucky. However, I think the story submitter pronounces wireless VOIP dead far too early. If, at this early date in the life of the technology, a Mickey Mouse set-up like mine can work, then the future for serious, enterprise level applications seems bright.
IMHO the VOIP RFC for WLAN was OK, FWIW.
But IIRC, its FUBAR WRT the FCC and maybe IRS.
A FOAF says the MSFT will BSOD it b/c its w/o DRM.
IAC, the US DOJ, FBI, CIA & IRS also dislike it.
So FTTB VOIP WLAN is SOL. HTH... HAND! -JPH
I've used Skype ( http://www.skype.com/ ) quite extensively (windows only at the moment but they have a linux version in the works) over my LAN and via my cable connection to people ranging from 160 miles away to people in other countries.
Sure, there is a slight "houston, this is tranquility base) type of delay, but within a couple of hours use this becomes second nature.
Many of the calls I made exceeded one hour in duration, god alone knows what they would have cost via telephone.
Every call was end to end encrypted, yes, even the voice signal.
To call what is effectively a brand new technology which is basically still in public beta DOA is nothing other than complete and utter bollocks and a sure sign that whoever is applying such a label to VOIP is either...
a/ terminally fucking clueless
b/ blunkett (UK) / cheney or rice (US) / a telco shitting themselves.
BT has just started rollout of 21CN which will involve the ENTIRE NETWORK moving over to IP based traffic routing, so some 30,000,000 telephones in the UK alone will be, guess what, VOIP within a few years... link here http://www.theregister.co.uk/2004/06/09/bt_ip_net
Slashdot is rapidly declining to the point where Pissy World (UK) / Fry's (US) sales staff will start calling what THEY percieve as stupid clueless customers as "slashdotters" as a term of generic abuse.
"News for Nerds" ??? Give me a fucking break, Twaddle for Teletubbies is more accurate a decription of the content lately.
http://slashdot.org/~GuyFawkes/journal
Can you hear me now?
urk, what a concept.
couple it with the ability to pick up subvocal sounds from sensors near your voicebox and we'll end up like the Belcerebon people of Kakrafoon (HHGGTG reference)
As if the plagues of mobile phones aren't enough (people talking in restaurants, cinemas, while driving), freed from Telco mobile charges it could become a real social concern if it isn't DOA but merely pining for the fjords.
HHGGTG quote: The Belcerebon people of Kakrafoon used to cause great resentment and insecurity among neighboring races by being one of the most enlightened, accomplished and, above all, quiet civilizations in the Galaxy.
As a punishment for this behavior, which was held to be offensively self-righteous and provocative, a Galactic Tribunal inflicted on them that most cruel of all social diseases, telepathy. Consequently, in order to prevent themselves broadcasting every slightest thought that crosses their minds to everyone within a five-mile radius, they now have to talk very loudly and continuously about the weather, their little aches and pains, the match this afternoon and what a noisy place Kakrafoon has suddenly become.
At our Uni, we have 6 campuses over the eastern seaboard of Australia (over 4000km apart). I work in the Infrastructure team and we have been running VOIP since 2000. We are all using AARNET for WLAN traffic and VOIP works wonderfully (CISCO callmanager, CISCO 7960's phones and CISCO infrastructure). Any non-campus (other than Australia University traffic) phone calls (local or interstate calls) hop off at the nearest local AARNET node onto the old analog exchange to the phone number you are calling. This gives us local phone calls all over Australia! The reason it works so well is that AARNET has QOS. In the US, this is a problem and VOIP will never work as well. We are also starting to use Video over IP using the same network. About the only problems we have had is worms and viruses in the AARNET network, but we have blocks into the network and at campus boarder routers that stop this kind of thing happening (most of the time).
At my office, I have MCK units in the company's two buildings talking ADPCM32 over bridged D-Link 2000APs (yes, I'm a cheap bastard, but I was saving company money!) through a FreeSWAN/PIX VPN. Nine lines total, plus the usual data traffic. Works beautifully (as long as the APs don't freeze).
You can simulate a VoIP call and get the MOS voice quality score. So if you want to see how your Wireless setup fares, visit testyourvoip.com.
Even if you don't care about VoIP, it is a useful test of the latency and bandwidth of your connection. VoIP is pretty sensitive to late packets so this tool highlights connectivity problems.
-ben
...one of our plants in Ohio. The install was a little rocky, and many of the features you'd find in any circuit-based system were simply non-existant or poorly implemented.
Now, that said, I put the system on its own POE switches and isolated network. Nearly 100 phones and the voice quality is superb. As a matter of fact, I had to introduce some comfort-noise because if nobody was talking, you couldn't tell you were even connected to anyone. It was really that clear. The POTS connection was done with a single PRI span, so calls were digital end-to-end.
I had to place two of the ephones on a remote end of a 10MB fiber link. They worked flawlessly. I then tried a single phone on a WIFI bridge, and it worked flawlessly.
Back to the article... The protocol the phones talk to each other using is g729. It uses roughly 9.6K worth of bandwidth, and sends packets every 20ms or so. A quality secured WiFi connection without any interference can support at least 25 to 30 phones before you start having channel speed or bandwidth problems.
In summary, a properly architected system has NO problems, whereas a system implemented over old, crappy hardware will have problem after problem.
LOAD "SIG",8,1
LOADING...
READY.
RUN
First of all, full disclosure: I work at Avaya, for their security practice. What I'm about to say may seem pretty self-serving for the company, but I can only hope my posting history establishes me as some sort of credible source.
Second warning -- I'm actually raving about my own company's gear here. I'm way more likely to get in trouble over this, but heh -- can't let an entire nascent industry get tarred over a temporary generation of *ahem* lesser performing equipment.
So, warnings aside -- I was at Hivercon last year. Hivercon's a fun show, set in the middle of Dublin, Ireland (which, btw, is a fantastic city.) I'm sitting there, on:
1) My laptop
2) Wireless
2.1)HOTEL wireless
3) VPN (IPSec w/ 50% packet overhead!)
4) An international link
5) VoIP into a conference call
By all rights, the quality should have been awful. I mean, it had every right to be...
Now, we have VoIP at home too -- Vonage, to be specific. Our Vonage link runs over an 1.5mbit SDSL line provided by Speakeasy/COVAD, is QoS'd at our firewall, and connects directly to our home telephone wiring.
The quality on the international, wireless, IPSec'd, laptop'd conference call through my Avaya softphone exceeded what I was used to from our home VoIP provider. It was basically landline equivalent -- yes, it was even better than my cell phone.
I was _shocked_. I remember PowWow, FreeSpeak, and all those other systems that ran VoIP over Modem lines. In what alternate universe did VoIP become a quality leader under difficult network conditions?
Turns out that implementation matters. I went and harassed some of the people who worked on the phone equipment (heh Brian) and asked how this system could possibly be working at all. Apparently Avaya got a bunch of the people from Bell Labs (it came from Lucent, which came from AT&T, which itself came from Ma Bell), so there was all this knowledge lying around already in how to manage reliable communications like lives depended on it. The big things being used were:
1) Error Concealment
2) Dynamic Jitter Buffers
Error concealment is simple -- there's necessarily 50 packets per second on a 20ms-latency link (1000ms / 50 packets per second = 20ms of audio per packet), and speech is massively redundant. So rather than simply dropping out when packets were missing, the voice client was "filling in the gaps" with neighboring content. Since the overall frequency profile was kept relatively consistent, short term drops were kept outside the range of human perception. Neat -- obvious, and not entirely unique to this particularly implementation (there's direct support for concealment in some of the G.72x codecs), but neat.
The dynamic jitter buffers are cooler. The basic idea here is that some links are high quality and others are less so, and sometimes the quality of the link will change in the middle of a call. As a response, the Avaya architecture will negotiate a longer buffer for packets to be stored before they're output to the listener to be heard. This buffer starts at ~10ms and can scale up to ~300ms -- distracting, but users have been accustomed to higher latency through their love of cell phones (sad, but true). The key is that the human auditory system can't easily detect speed changes at subsecond resolutions, so you simply execute a non-pitch-shifting slowdown of output speech over a second or two and now you've got a jitter buffer far more tolerant of inclement network conditions. Mind you, this is an absolute nightmare for automated testing equipment, which expects time to be constant, but it's great for everything else -- even TTY's! You'd think a 150bps modem could travel over any link, but apparently not...
Anyway, we keep hearing about how Motorola and Avaya are putting out some kind of VoIP phone, so I'm actually pretty hopeful that we'll see a GOOD VoIP/WiFi solution sometime in my lifetime. I can say this much, though -- simply spurting ulaw on the wire and calling it VoIP ain't my idea of a good time.
--Dan
bandwidth, packet loss, high latency, bad optimization (of qos,etc) to name a few
Maybe one day, but right now the technology isn't there, and the need/reason/means isn't that strong in a lot of ways. People have cell phones, and for most those accomplish all that is necessary. There are already devices connecting over cellular networks that can accomplish everything needed for many people.
Down the road I bet the networks will mesh together, and the wifi, cellular and others will start to be one big network operating in small clusters to keep things running smoothly. We can't handle that kind of bandwidth and that many users now, but who's to say we won't be able to in 20 years?
I just doubt that the separate wifi and cellular (and other) standards will persist side by side for all that long as convergence quickens.
Presently here, but not there.
Furthermore, there's no possible way to order all of the other devices that are causing conflicts on 802.11x to shut up... there's no promise that the interfering device is even part of your network! In fact, there's no promise that the competiting device is even a WiFi device.
IP is nothiing but extra overhead that really isn't needed over a "last inch" network hop.
I agree with other posters that one conference failure does not a funeral make. Slashdot gets enough traffic without having to sensationalize everything.
However, the current state of WiFi is pretty sorry. Perhaps I am just flustered because of the problems I've had setting up a WiFi network for the first time, but everyone I know who has setup WiFi has had to deal with a whole array of perplexing problems. Without fail, they end up consulting with tech support to get the connection to work. Many router reviews I read on-line detailed mysterious problems and uneven user experiences. On the other hand, connecting Ethernet is practically like plugging power in an outlet nowadays.
I'm not tech-illiterate. I've built every computer I've owned since high school and have run Linux variants on each of them at one point or another. I don't mind some technical complexity, but setup should be easier than it is, and the connection more reliable.
At this point, I could launch into a rant about cell phones as well. CNN had an article today about growing customer complaints with cell providers in the US. In related news, java.net's front page is leading with a blog and associated discussion about how the current speed of software development is going to get the industry in serious trouble.
I think someone should write an article about the death of the IT industry as a whole. Computer-based consumer electronics and software have an amazingly poor degree of reliability, and there appears to be little liability on the part of companies and few channels of recourse for consumers. Well, </bitter>. I'm going off to enjoy my newly configured WiFi.
======
In X-Windows the client serves YOU!
Technology needs time to improve and mature. This is something we refuse to accept today.
Essentially, what we need for VoIP over "any network" is bandwidth allocation based on QoS.
This QoS capability must happens at various OSI layer, like physical layer 802.11, and/or network layer IP. (Transport and application layer QoS are not as effective.)
From IP to IP perspective, IP QoS will be the key for good VoIP.
From WLAN only to WLAN only perspective, WLAN QoS will be beneficial.
In a hybrid physical layer network, with backbone+broadband+ethernet+WLan, IP QoS is the way to go for good VoIP.
However, current IPv4 does not support the needed QoS effectively, and IPv6 is suppose to hold the promise. Ironically, we also see that IPv6 deployment is very slow.
In short, my take is - existing 802.11 is good enough for VoIP, and the problem is actually on the current IPv4, which is not capable to handle QoS.
Hey, that's my password you are typing
If you RTFA, the guy is whining about latency. Wireless, in this case 802.11, and specifically Direct Sequence Spread Spectrum digital transcievers often employ more than one forward-error-correcting protocol to get around the horrible bit-error-rates. For most packet traffic, a little latency is an acceptable price to guarantee that more packets pass their checksum. For streaming audio/video this is not so.
Not knowing exactly what was going on, I'm going to guess that his connection was really bursty, possibly due to other 802.11 traffic and also possibly multipath interference aggregation problems with many RF sources in the same band in a confined RF reflective space. If I were a latency-sensetive streaming protocol, I would buffer a little bit, and cut out a lot. I'm thinking I would probably flush a lot of bytes from my buffers because they got too old before I could assemble a meaningful blast of audio.
If this kind of thing sold access points, then 802.11 chipsets would have a sideband that tolerates more packet error and less delay. That would allow you to turn on "interference robustness" and still make a phone call because it doesn't use "interference robustness."
--- Nothing clever here: move along now...
VoIP over WLAN has just started. If you work for an intrenched Wireless Phone provider or a Baby Bell you wish that VoIP over WLAN was dead and this is probably just the beginning of the FUD from these guys and their pawns in an effort to hold on to their customers. So my answer is no.. its not dead.
I'll admit to being surprised at the use of IP for plain old telephone service. I always thought the interesting applications were those involving multiple media -- shared slides (with pointers and scribbling), shared apps, some low bitrate video, etc. I remember a whole series of very effective four- and five-way meetings between the developers of an authoring system in Denver and the people using it to write training materials in Minnepolis.
I don't think this fellow tried very hard. The company I work for just replaced all of our phones in our local office (500+ people) with a VOIP system, including wireless VOIP phones for many. While they had to iron out some issues early on, the system (and more to the point, wireless VOIP via a wireless LAN) is working extremely well. (Unfortunately I don't know the specifics of the system off-hand)
Seems like Mr. Kewney has an alternate agenda, or is just really quick to jump to conclusions.
This phone
/ ps 5056/index.html
http://cisco.com/en/US/products/hw/phones/ps379
Totally rocks! - I have over 100+ installed - no problems whatsoever - crystal clear
VOIP over WLAN Dead? No fucking way IMHO
I've can even war drive with it! It will hop on any wide open access point connect and go - mind you QOS is dicey - but it's fun anyway to have it hop on some dummy's access point and then 4-digit dial someone at the office.
---- "Logoff! That cookie shit makes me nervous!" - A. Soprano
> VOIP over WLAN is not DOA. If you tweak the QOS etc
IANAE, but perhaps change the TCP/IP settings so you dont waste so many SYN/ACKs then upgrade the WIFI to 802.11g perhaps with a VPN/IPSEC or maybe SSH over RF ASAP. FWIW the WAP shoud be IEEE standards compliant, the company who sells it should be ISO9000 compliant too. HTH.
The stuff should Just Work if you install it out of the box, as long as you're not getting too much interference from microwave ovens, 2.4GHz cordless phones, etc., and as long as you do something with traffic shaping to handle slow cable/DSL uplinks, but it's possible to do it badly, and the columnist appears to have reviewed what happens under near-pessimal conditions, and appears to be surprised that that didn't work.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
Yes, all the carriers use VoIP on their backbones, about as controlled an environment as you'll find. The real question is VoIP to the endpoints, particularly over wireless. The answer is -- it's doable, but you need a much more aggressively correcting implementation than what's commonly deployed.
Cell nets aren't LANs, btw -- they're either MANs or WANs. There are real differences -- in protocol, in problems, in nature.
--Dan