[asterisk-users] SIP vs Analog lines

[Miguel Molina]

Steve Totaro escribió:
>
>
> On Tue, Jul 28, 2009 at 9:13 PM, Miguel Molina 
> <mmolina at millenium.com.co <mailto:mmolina at millenium.com.co>> wrote:
>
>     John F. Ervin escribió:
>     > Never having actually rolled an Asterisk (Trixbox in my case) system
>     > into production.  I was wondering if in most peoples opinion if
>     given
>     > the choice would rather have a straight VOIP/SIP system or would
>     > rather have a system with normal POTS/analog types lines and
>     something
>     > like a digium card?  As far as reliability etc.  Thoughts?
>     I'd go VoIP without thinking twice.
>
>
> Always think twice and always look both ways before crossing the 
> street.  Look left, right, and then left again....
Very true, I just wanted to emphasize that VoIP with asterisk is a great 
alternative on many scenarios.
>  
>
>     We are on the 21st century! Many
>     technological efforts that have been made through all this years have
>     been directed to bring telephony to the IP world. 
>
>
> While true, I also have read that unless major upgrades are done, P2P, 
> YouTube, other streaming, and tons of other bandwidth intensive apps 
> are going to bog down the net in many spots.  Hopefully it is not one 
> of your hops to your ITSP.
That's why QoS exists. Make P2P bog down, not "golden" VoIP packets. 
Again it's about network design, management and quality of the provider. 
IHMO running VoIP on the open Internet is possible, but doing it 
carefully, not throwing just hundreds of simultaneous calls to see how 
well they work. And accepting that not always the quality will be the 
best. If you can't accept the downs of it, ask for a dedicated link 
between your places.
>  
>
>     Asterisk has played
>     and keeps playing a pretty nice role on the open source market we are
>     in. VoIP will be as reliable and good quality as your network is.
>
>
> Your network, your ISPs, or your provider?  If it is just "your 
> network" then you must be speaking of TDM.
I'm speaking of LAN part of the network doing VoIP calls, where the 
quality of switches and good design are key, and where the bandwidth is 
definitely plenty and free.
>  
>
>     The
>     savings of not having to make double phone/data cabling and the
>     advantages of VoIP are now a standard worldwide, from carriers to
>     small
>     home PBXs.
>
>
> Most new cable jobs run cat5 or cat6 regardless of use for almost the 
> same price.  I actually don't know of any cabling outfits offering cat3.
>
> Most existing workspaces have data jacks already in place.
>  
>
>
>     Analog lines are definitely legacy. The last time I put a T1 channel
>     bank into use was more than two years ago, and never had to configure
>     another one since then.
>
>
> I "think" he is just referring to a small amount of lines, although he 
> did not say explicitly.  I don't know about a channel bank (except for 
> a whole bunch of fax machines)
Yeah that was a little less than the full 24 analog lines connected to 
the channel bank. That got replaced with some VoIP phones and softphones 
connected to the asterisk PBX of the company.

Finally I was comparing analog POTS lines to VoIP in PBX applications, 
where the differences are huge in terms of configuration and 
infrastructure efforts, features, and with use of telephony cards, 
reliability. TDM is another story, and better than VoIP on some aspects, 
like stable audio quality, good detail of hangup causes (Q.931) compared 
to SIP response codes and so on.

Regards,

-- 
Ing. Miguel Molina
Grupo de Tecnología
Millenium Phone Center

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