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You Don't Know Jack about VoIP
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."
here you go
Trolling is a art,
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
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?
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
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 $4 extra that you can place anywhere in Canada. So even though I live in Edmonton I could have a local number in Toronto that I could make local calls to there from. Also people could call me on that line locally and it would ring here in E-town.
--- to swing on the spiral...
Unless you're one of the unlucky who has to use a DSL provider which requires you to pay for a landline to get said DSL service. Then you're stuck in a bit of a pickle. Hopefully that will change, I seem to remember hearing about laws regarding that problem.
In Germany, you can get a DSL line from the big telco ex-monopoly, and quality Internet service from a local provider. It's a bit like B-ISDN, as it was originally proposed (but, of course, without any bandwidth and latency guarantees), only with IP signalling (mostly PPP, and L2TP for inter-ISP links) instead of ITU protocols. The only downside is that you can't get that DSL line without a PSTN line. There are other DSL offers, but those are tied to specific ISPs.
Sounds like your system is not set up correctly. You should be able to transfer a caller to (extension)#2 and send the caller to (extension)'s voicemail. There is another config to allow prepending a digit or * to the (extension) to send to voicemail.
As long as the phones and a voice gateway have power, the survivability feature should keep some voice services active in the event of power failure.
911 works well, as long as there is a gateway with a POTS line at each site. Otherwise, you've got to do the E911 stuff, and maintain the data.
Don't pick up the pho*(@)$*@&@!@ NO CARRIER
>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...
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.
First off, I found the article kinda ho-hum (yeah, I read it...what was I thinking RTFA?). I've come across better articles on the net from such odd sources as USA Today and such. I will admit though that the last page had a few things that made me go "hm", in particular how they remind us that monitoring this system will cost a pretty penny.
I've been doing research for a client that is wanting a VoIP/call center solution. When I started, it was fairly simple. Looking at the different services offered (Vonage, Broadvoice, Broadvox, Packet8 looking like the best solutions so far) and then I went to look at Cisco gear and see what it would be to set everything up yourself. And then I looked at some IP PBXs from 3Com, Avaya, Siemens, and Zultys. You know what guys? We've got quite a load of solutions out there for someone who wants VoIP. And these were all hardware-based...I didn't even bother looking at software-based solutions.
I'm finding this whole VoIP thing to be just as interesting as WiFi...a wild new market with everyone trying to establish a foothold (remember the dotcom days with everyone trying to grab as much marketshare as possible?) and then weather the storm and see who survives. Interesting indeed.
"He uses statistics as a drunken man uses lampposts...for support rather than illumination." - Andrew Lang