[LUNI] OT: VoIP Satisfaction
kris at krisk.org
Thu Mar 10 23:32:20 CST 2005
Benjamin Mayer Stocks wrote:
> Hi All,
> I've been thinking about VoIP recently and I was hoping to get the opinion
> of those of you who have it in regards to:
> 1. Linux compatibility
> 2. Quality of the service (delay, jitter, audio quality)
> 3. Quality of the provider (please provide name of provider)
> 4. Cost vs. traditional POTS service
> I hope this isn't too OT but I know I've seen Vonage's name tossed about
> here so some of you must have VoIP.
> Thanks so much,
Hello, I am new to the list but perhaps I might be able to help you
with your query.
1) What are you looking for under Linux? A server/proxy solution like
Asterisk or SER? Or a softphone like X-lite. Please elaborate.
2) As I'm sure you know, it depends. I work primarily with Asterisk
and it's IAX2 protocol over any WAN/Internet links. It seems to handle
poor connections at least as good as SIP, and there is some new
JitterBuffer and Packet Loss Concealment code that Steve Kann (a major
IAX2 developer) has been working on. I believe that it is either in
CVS-HEAD or getting close.
3) It largely depends on the provider and technology. Many providers
it seems are experiencing growing pains here and there. Just because
they work for someone at a given time does not mean they will work well
for you and your connection. I would say one good way to at least
narrow the field down is to find out the following:
3a) What codecs they support (g711u, g729, g726, etc.)? While you can
never get away from the overhead associated with IP/UDP, codec selection
is important. For instance, G729a has a bitrate of 8kbps compared to
64kbps for G711u. It doesn't take a genius to figure out that you can
use G729a on a connection with half the bandwidth of G711u (or jam twice
as many calls through the same pipe).
3b) The hostnames of some of the provider's PSTN gateways. This will
allow you to do traceroutes and pings to them. Two of my IAX2 providers
(NuFone and iax.cc) seem to have very good IP connectivity in Chicago
and are no more than 12ms away from me. Did I mention that this is on a
DSL line from SBC in Lake Geneva, WI? On a good connection in the
Chicago metro area you could probably do a lot better.
Overall, it is probably going to come down to the quality of your
internet connection. If you have a T1+ to a major provider, you
shouldn't have a problem. Next I would pick DSL, and then cable. Cable
seems to have higher packet loss and latency.
4) Again, it depends. What are you looking to do? For a single line
installation for a residence or something Vonage seems like the most
foolproof. For the do-it-yourself-er in such a situation I recommend a
Broadvoice (www.broadvoice.com) BYOD (Bring your own device) account and
purchasing a Sipura SPA-3000. They have some pretty unbelievable plans
to chose from and purchasing your own ATA allows you to do some pretty
cool things (especially one like the SPA-3000). It can be bought from
somewhere like Voxilla for under $100.
... WARNING: SHAMELESS PLUG FOLLOWS....
For a business or more hobbyist install, I really recommend taking a
look at Asterisk, or maybe even AstLinux. AstLinux is a Linux distro
that I created for running Asterisk in embedded applications. It runs
from a 32mb Compact Flash card and fits in 27mb! You would have to look
at my website for more information:
... SHAMELESS PLUG ENDING...
You can then use your Asterisk (www.asterisk.org) install to connect
any of your voip devices with each other, voicemail, conferencing,
T1/E1/POTS hardware, other Asterisk systems, SIP phones/ATAs, etc.
Pretty much anything that you can think of.
Take a look at http://www.voip-info.org and listen to the
Asterisk-users mailing list for a while. If you are at all interested,
I guarantee that you will be hooked in no time at all!
Hopefully I have given you a lot to think about!
P.S. - I hope that I didn't offend anyone with links to AstLinux. I
just finished 0.2.2 yesterday so I am still pretty excited about it!
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