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.""

Comments

sataphone

[Cyberglich]

Well i have used stantaphone over my home wifi worked ok (1-1.5 sec delay) normal for anything of that nature.

Re:sataphone

[dasmegabyte]

I've used iChat over my wireless lan to my boys in Cinci who ALSO use wireless lan. Not only was there no lag at all, the clarity was better than any phone I've used.

Stanaphone worked for me:

[Xshare]

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.

The 802.11 basic standard does not support voice!

[Ho Kooshy Fly]

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

VOIP over DSL isn't much better

[EmbeddedJanitor]

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".

Re:VOIP over DSL isn't much better

[UserChrisCanter4]

And that would be where QoS comes into play. If his company set that system up for him, shame on them for not making the obvious assumption that the connection might occasionally be heavily utilized for data at the same time a call is being placed.

If he set this system up himself, tell him to go get one of the linksys/netgear/whatever router/gateways in a box that support QoS (it's usually the units a step above the basic ones). If his router or gateway is a linux box of some sort, get it setup on there. If he's using Vonage, their VoIP adapter supports it if connect it in front of the PC/router/what-have-you.

Re:VOIP over DSL isn't much better

[rgbscan]

I was working on a VoDSL product based on the HomeRF protocol a while back during the whole dot.com thing. The protocol worked rather well for this sort of thing. The protocol knew o turn down other traffic when it saw a becaon for voice data. Too bad it didn't catch on and we're trying to bolt QOS over into the 802.11 world.

Re:VOIP over DSL isn't much better

[Tony Hoyle]

This is one of the reasons VOIP can't be justified at the moment.

eg. at home, the cheapest VOIP phone is 50UKP (compared to 2UKP for a cheap POTS phone), and you need an asterisk router to make it all hang together if you have more than one phone. Oh, and an FXO as the VOIP carriers are all 2-3 times more expensive than regular POTS and you'd be stupid to use them at the moment (in the UK it's impossible to have DSL without paying the full rental for a POTS line anyway so there's no rental cost saving).

If the DSL line goes down (not infrequent) all the phones are out, except the main analogue line which has the asterisk machine plugged into it...

It's worst at work - I had to price a system (was in the wrong place when VOIP was mentioned in front of PHB). 60 Grandstreams is still damned expensive, plus a 60 line FXO/PBX. Then I found out that simple things like call forwarding didn't work -you need a more expensive phone for that, so more cost. When I gave the final figure to PHB he nearly had a heart attack! Needless to say the company will not be investigating VOIP for another few years.

Re:VOIP over DSL isn't much better

[Col. Klink (retired)]

> To use a telephone, you go to the local thrift store, spend $5 on a phone, and plug it into the wall to get reliable telephone service.

Yes, to use your OWN telephone. But if you want to telecommute and be on the corporate PBX, VoIP is the ultimate solution. You can have the same number for days when you are in the office, at home, or on travel. All calls you make come out of your office PBX and not your home phone.

Re:VOIP over DSL isn't much better

[tftp]

Grandstream phones are really cheap inside, very shoddy manufacturing etc. etc. Most of them work, but you must buy extra 10% for spares. I have one phone here that just refuses to recognize network... sometimes :-) I opened it up and inspected soldering, seems to be OK but still the phone is defective. And they also love to ARP-flood your network, you need to check the configuration with a sniffer to be sure they behave.

However a working SIP phone with Asterisk is great. I had more problems with two analog phones than with 10 SIP ones.

At some point I even had some of these phones bridged over 802.11b - no phone-related problems (but plenty 802.11-related ones :-) Now they are on 100 Mbps cable, though - more reliable.

Re:VOIP over DSL isn't much better

[_Brazil_]

But QoS would fix that...

At my old apartment, we had ADSL, and my roomates were Counter Strike nuts... and would come to my room yelling at me for doing p2p stuff to runin there ping times...

I refused to stop my file trading, instead, I made my Linux box router use QoS... I made certain services have higher priorty, as well as in general, small size packets have higer priority...

It wouldn't matter how much I was uploading or downloading... their CS ping times stayed the same...

Plus what you are discribing is 2 problems...
if your upload speed is slower than your download speed... you can't upload response/acknoldgement packets back, and reduces your speed to the effiecientcy of your upload...

Point is... VoIP over WLAN is possible... just takes some fine tunning...

Why would you want your e-mail packet have a higher timming priority over your VoIP packet? Or enven the same priority?

Re:too early

[BWJones]

Shoot, we used iChatAV rather successfully from Auckland, New Zealand to Salt Lake City for remote collaboration in a lab environment rather successfully with hardly any delay whatsoever. In fact, I routinely used (and still use) iChatAV with a wireless connection, so I do not understand what this is all about.

Works fine at my house

[Gaewyn L Knight]

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.

Works for me..

[jcr]

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

Skype

[minairia]

I use Skype over my wireless home network via a cruddy 4 year old laptop with a no-name wireless card and the cheapest Linksys wireless router I could find. I connect to the internet using SprintBroadband, a kind of wireless DSL that's beamed to users via a big antenna. Even with two wireless links, I get a perfect connection 99% of the time. While on Skype, I can surf ordinary news, etc. sites fine. Trying to play a video at the same, admittedly, will be system slow to a crawl..

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.

Re:VOIP over WLAN?

[stevenbdjr]

Is it just me, or am I the only one who ever thought this was completely stupid?

You just haven't seen it used in the right environment. VoIP over WLAN is perfect for a multi-building campus-like environment with roaming users. Instead of building a single-purpose analog infrastructure to support Spectralink-type phones, you can invest in building a data infrastructure (or use an existing one) that supports both your computing resources and your telephone systems. Plus, many of the industrial VoIP wireless handsets support push-to-talk, making them perfect replacements for your maintanence crew's walkie-talkies.

If you're using decent enterprise-class AP's (Cisco, Enterrasys, Proxim) which support QOS, call quality is quite good.

No problem here

[maxic]

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).

Test your connection out

[fiji]

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

I just put a Cisco VoIP system in...

[eric2hill]

...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.

Re:Good idea

[sunilonline]

bandwidth, packet loss, high latency, bad optimization (of qos,etc) to name a few

Re:too early

[sg3000]

> shoot, we used iChatAV rather successfully from Auckland,
> New Zealand to Salt Lake City for remote collaboration in a lab
> environment rather successfully with hardly any delay
> whatsoever

Yeah. I do this all the time.

Ingredients:
1. PowerBook G4
2. Mac OS X 10.3
3. iChat AV
4. AirPort (802.11b version)
5. Comfy bed, little computer lap tray, Collie sitting on your feet (all optional)

Results: no problem at all. No delay noticeable. Voice quality was fine. Voice quality was so good, the whole thing was kind of anti-climatic.

Re:The Mike

[JPriest]

For US users, you can pick up Zalman headphones here for $44, you can add a clip on Zalman microphone for it for another $8.

The key to good VoIP is QoS primarily

[toesate]

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.

It works well.

[tarak.org]

Its all in the connectivity and the speed of the device getting the call packetized and placed on the wire. I use my softphone on my laptop with a 802.11b PCMCIA card at home through a Juniper SSL VPN with consistant success and quality. I have installed VoIP phones that connected to a gateway for call setup and tear down over a wireless bridge with good success. I have also experienced the mediocre quality of the DialPad's/Net2Phones etc.. If the device doing the codec compression can get the packet on the wire fast enough and there is enough throughput for the call. The call will succeed and be quality, WLAN's included. If the network is already taxed and the device doing the codec compression/and or call setup and teardown is taxed (in the case of some of the VoIP providers) the call will suffer.

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.

Re:The 802.11 basic standard does not support voic

[michael_cain]

I started doing VOIP applied research while employed at one of the big telephone companies twelve years ago (at least). The same basic rules that applied then apply now. VOIP can consistently provide telephony-like service -- high-quality audio, low round-trip latency -- under one of two conditions: (1) some form of QOS, or (2) swamp the problems with bandwidth. For most LAN situations (not all), switched Ethernet is sufficient to provide the "swamping" solution. Unfortunately, wireless CSMA is shared and seldom gets into the "swamping" category. QOS can take a variety of forms, from packet-by-packet prioritization, to traffic segregation and call-by-call admission control.

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.

Cisco Rocks

[bizitch]

This phone

http://cisco.com/en/US/products/hw/phones/ps379/ ps 5056/index.html

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.

Re:No Mr. Enderle.

[Anonymous Coward]

Funny you mention that. I was recently looking at the products of this company, which makes their own sort of 'wifi cellphone', as it were.

Apparently, they've been around for some time now. I don't think this industry is "dead," either...

Your company has Network Engineers

[billstewart]

But John, you work at a company that has really good network engineers doing their infrastructure, so they've made sure to do things competently and think of the important issues. (For instance, they were one of the early companies to figure out that you put the 802.11 _outside_ the corporate firewall and run VPNs over it.) They've almost certainly got enough switched lan bandwidth behind the Access Points to get good throughput, while the columnist was at a trade show where the network was overloaded, just barely stayed up at all, and was probably installed by convention center union engineers instead of techies. (That's not to criticize union engineers - the hardware is probably nailed to the wall securely enough you could stand on it, in a location picked for mechanical stability, rather than attached to the radio-propagation-optimal spot with duct tape like a techie would do.) VON is probably a much more benign networking environment that, say, DEFCON, but the standard VOIP codecs aren't good at high latency and high packet loss which were apparently a problem for even regular data. Skype uses some of the codecs from GlobalIP which are designed to tolerate higher-loss environments, so it would have had a better chance,

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.

Re:No Mr. Enderle.

[poot_rootbeer]

Phone calls work better when circuit switched...

IANATE (I am not a telecomms engineer), but from what I was told in an engineering class at university a few years ago, POTS service is only circuit-switched from the handset to the local phone company's central office. Everything that travels long-distance over the phone backbones is packet-switched.

Re:No Mr. Enderle.

[Keithel]

They've since updated the firmware -- about 5-6 days ago.. If you've got a Linksys router, check out the support page..