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You Don't Know Jack about VoIP

Posted by michael on from the single-purpose-phone-lines-so-old-skool dept.

gManZboy writes "Phil Sherburne and Cary Fitzgerald, two senior technologists over at Cisco, have written an in-depth overview of VoIP for developers and the like (not for everyone who's ever used a phone). Like Queue's earlier You Don't Know Jack about Disks, this article covers the history, the basic technologies, how they work, and where they're headed. If you found the blog post yesterday lacking, check this one out."

16 of 113 comments (clear)

  1. Re:wheres the link:"you don't know jack about disk by grub · · Score: 5, Informative


    here you go

    --
    Trolling is a art,
  2. inevitable by scaaven · · Score: 5, Insightful

    voip will take over. Voice can be transmitted at such a low bandwidth, and all the cost to make a connection anywhere in the world is the cost of your ISP. I think they have them, but you need to have some sort of program always listening on a port from your IP, and transfer incoming calls to a usb connected phone that rings. Then you'd have all sorts of spam bots calling everyone's IP, so you'd have a list of approved incoming IP's or a numerical code that allows your call.

    --
    I know I'm going to be modded up on this
  3. Test your connection... by fiji · · Score: 5, Informative

    Before you waste time trying to get VoIP (or paying for VoIP from a provider) going it is worth testing your connection to see if it can support VoIP calls at a reasonable quality. You might want to test your line at various times during the day... I get crappier calls in the evening.

    Anyway, http://testyourvoip.com/ provides a decent free testing serice just using a web browser.

    -ben

    1. Re:Test your connection... by Nos. · · Score: 5, Insightful

      Some other things to think about before switching completely over to VOIP... what happens during a power outage? You're POTS line will still work, but your VOIP probably won't, unless you are providing backup power. Not to mention your *11 services (411, 611, 911) may or may not work depending on your service provider. Also, even if they do not connect you, they may not be able to locate you. One of the best feature of 911 is the ability to locate the source of an incoming call in case the caller is unable to speak.

    2. Re:Test your connection... by Vancorps · · Score: 3, Interesting
      This is really what's slowing down adoption of VOIP in the home. Here at the office we currently use Cisco VOIP but we're switching to Televantage because Cisco's sucks so bad. Amazing how many features weren't well thought out. I mean, it takes 5 steps to transfer a call to voicemail.

      At any rate, I wouldn't think it would be a problem for VOIP providers to integrate with 911. They have the address of all their customers, seems like it would be trivial to have a 911 operator send out the request and an automated response would reply with the address. That would solve the problem of not being able to find the person trying to call.

      As for a power outage, we had one recently and our cisco poe switches kept all the phones up so most of the building had no idea the servers were no longer receiving power.
    3. Re:Test your connection... by Nos. · · Score: 3, Interesting

      At any rate, I wouldn't think it would be a problem for VOIP providers to integrate with 911. They have the address of all their customers, seems like it would be trivial to have a 911 operator send out the request and an automated response would reply with the address.
      I've done some work for a VOIP service provider. The way their system works, they don't know your current location. Sure, they know your home address, but with their setup, there's nothing to say I didn't take the box to my friends place, plug in to his high speed and make the call. This is why I like the service I worked on. The service comes with a little box (about the size of those home routers) that you plug your high speed into and a regular phone, and away you go. As long as you have high speed and clear access to the ports needed, the service works. Sure, your bill gets mailed to your home address, but that doesn't mean that's where your making the calls from.
      As for a power outage, we had one recently and our cisco poe switches kept all the phones up
      That may work in an office environment when the phones are hooked up to the switch, but what about at home, when your VOIP is over cable or phone line? No power, no dial tone.

  4. Oxymoron by StevenHenderson · · Score: 5, Funny
    have written an in-depth overview of VoIP

    This is a great statement to read while eating some jumbo shrimp.

  5. Re:VoIP = fad by Ugodown · · Score: 3, Insightful

    I don't think it's a fad, this year I am getting VIOP from Primus Canada. Finally I can say "screw Telus" because I am getting cable Internet from Shaw and phone through Primus. It's a good feeling.

    --
    --- to swing on the spiral...
  6. Which service is better? by exhilaration · · Score: 4, Informative

    If you're in the market for a VOIP service, Geekbooks did a pretty decent comparison of different services. Does anyone have any other links?

  7. Re:What we want from Pa Cisco by jaymzter · · Score: 4, Informative

    Your comment sounds pretty interesting, since you seem to know what you want, but apparently haven't looked anywhere other than Cisco.

    Avaya's IP telephony products provide your encryption, Cell+Wifi with auto switch over, and my favorite, all the servers run GNU/Linux! No video phones yet.

    I hear they're really expensive, but I really don't have any clue as to that, I just fix the stuff.

    --
    If thou see a fair woman pay court to her, for thus thou wilt obtain love
  8. Re:VoIP = fad by Ugodown · · Score: 4, Informative

    Yeah, Primus VIOP is only $20 /m when whith Telus it's at leas $30 /m for basic service. Plus you can have a extra line for $4 extra that you can place anywhere in Canada. So even though I live in Edmonton I could have a local number in Toronto that I could make local calls to there from. Also people could call me on that line locally and it would ring here in E-town.

    --
    --- to swing on the spiral...
  9. Maybe by paranode · · Score: 5, Insightful

    and all the cost to make a connection anywhere in the world is the cost of your ISP

    Unless you're one of the unlucky who has to use a DSL provider which requires you to pay for a landline to get said DSL service. Then you're stuck in a bit of a pickle. Hopefully that will change, I seem to remember hearing about laws regarding that problem.

  10. Re:VoIP = fad by bg_27 · · Score: 3, Interesting

    No way, my company pays over $10,000/ month in long distance for our 1-800 nubmers and all the long distance we use. The bandwidth you could get for that price is pretty good.

  11. No, not inevitable. Obsolete by Animats · · Score: 4, Insightful
    Cellular providers have had flat-rate long distance for a while now. That's what's really putting pressure on the wireline carriers. Now we're starting to see flat-rate long distance from the wireline carriers. Soon, at least for U.S. domestic calls, there will be no price advantage for voice over IP.

    Internationally, though, voice is still a cash cow. That may last a while longer.

    Voice over IP is more of an advantage for companies with elaborate internal telecommunications infrastructures. The VoIP gear is cheaper.

  12. Re:What we want from Pa Cisco by chipperdog · · Score: 3, Informative

    >Server software that runs on Linux for those of us that like a standard back office.
    like asterisk
    It supports many VoIP standards, pots, BRI, PRI, etc...

  13. BANDWIDTH is not free by vpreHoose · · Score: 3, Informative

    Where every Cisco VoIP system falls down is on the ammount of bandwidth required to support VoIP. From a telco operator perspective (voice or data) your greatest operational expendature is your bandwidth. Using IP or SIP costs you far more in bandwidth than is economic (when compared to alternatives). Yes you can multiplex voice and data but that takes even more bandwidth than doing it seperately! GSM is probably the most efficient way to carry voice over a digital channel. Does very well at 22kbit/sec. You even can do voice over GPRS at 33kbit/sec (the latency sucks, but you can do it). But try running a SIP session and it simply doesn't work. The protocol to establish the session and the overhead cannot be done on a low bandwidth channel. VoIP makes sence only when bandwith is free, but in the real world it isn't and the commercial imperative is to make the most of it.