Mark Kent <mark.kent@xxxxxxxxxxx> wrote in
news:nr8do3-f0g.ln1@xxxxxxxxxxxxxxxxxxxxxx:
> begin oe_protect.scr
> alt <spamtrap@xxxxxxxxxxxx> espoused:
>> Roy Schestowitz <newsgroups@xxxxxxxxxxxxxxx> wrote in
>> news:2796393.6OVKRngNiV@xxxxxxxxxxxxxxx:
>>
>>> Open Source Takes on Telecom
>>>
>>> ,----[ Quote ]
>>>| In 1999, Mark Spencer needed a phone system for his startup, Linux
>>>| Support Services. The company's aim was to provide technical
>>>| support to businesses and programmers for Linux, an operating
>>>| system for which the source code is free, making it an appealing
>>>| alternative to Microsoft's Windows.
>>>|
>>>| [...]
>>>|
>>>| Without realizing it at the time, Spencer was at the forefront of a
>>>| movement to bring open source to telecom. By 2001, Voice over
>>>| Internet Protocol (VoIP)--the technology that routes voice calls
>>>| over data networks--had started to take off. And it became clear to
>>>| Spencer that the market was ready for open-source telecom systems.
>>> `----
>>>
>>> http://www.businessweek.com/technology/content/jul2006/tc20060707_042
>>> 67 9.htm
>>>
>>
>> I think this article is misleading. Here's why:
>>
>> Asterisk was designed as a PBX, not as a softswitch. My experience
>> with it suggests that it is only good for small scale retail
>> applications. Any attempts to use it on a wholesale level have failed
>> miserably.
>
> Asterisk is a media gateway and softswitch combined. I believe that
> largest setup recorded is around 50,000 users, but I'd have to check
> back on that.
>
> Are you attempting to do codec conversion?
No. We're even allowing re-invites.
>
> Are you using IAX in and SIP out?
I don't use IAX at all. I deal with carriers and none of them even
consider IAX as a signalling option. It's either SIP or H.323, with heavy
leaning on H.323. I even have it disabled on my installation (no point in
having another port open and using memory I could use elsewhere).
>
> What do you mean by "wholesale level"? I'm assuming you're talking
> about TDM traffic with C7, but perhaps not?
Pure IP traffic. Asterisk running on a Dual Xeon server with 1GB of RAM
couldn't hack it. GnuGK running on a P4 with 1GB of RAM will handle a DS3
of Retail-type traffic (that is, wholesale traffic generated from retail
clientele of our clientele) quite well.
>
> I'm also fairly certain that the Tesco VISP offering is based on
> Asterisk. I also know that it's been used as a media server in some
> telcos, as well.
>
>>
>> It does not have the switching capability to match a GNU Gatekeeper
>> or an SER SIP Switch, let alone any commercial products such as a
>> Sansay VSX.
>
> SER is an app server and SIP proxy, it's not a switch, any more that
> Gnu gatekeeper is (h.323 gatekeeper, I think).
GNU Gatekeeper can act as a switch. We use it to mangle 50,000+ NANP
codes.
>
>>
>> This article calls "PBXs" telecom, but I know from personal
>> experience that PBXs are NOT telecom.
>
> Beg to differ!
Please do. The ex-telecom guys I work with (old switch techs) don't
consider it telecom. Perhaps it's just a semantic difference. But I see
"telecom" as Class 4/5 switching in carrier environments. Think "Telus"
or "Bell".
>
>> A Nortel DMS250 is Telecom. A Harris 20-20 is
>> Telecom (albeit, a bit old). These are switches that can handle a DS3
>> of predictive dialer traffic (which is absolutely horrible traffic).
>> Asterisk cannot do this. (The GNU Gatekeeper can barely do this).
>
> A DMS250 is an ancient box, no longer supported, and superseded by
> CS2k and passport, afaik.
Yes. I know that they are old. But they do the job.
>
> Any real telco-grade tandem switch can handle upwards of 50k bhca,
> which is the critical metric.
Dialer traffic will test that limit.
> Asterisk is a PBX, but you can have as
> many of them as you like, of course, so you're not limited in the same
> way as you are with a traditional C7/TDM switch.
>
>>
>> Asterisk is definitely making a run at the PBX market. I use it for
>> our office/personal use. We have 2 extensions in the office (located
>> about 30ft from the server) and another 5 or 6 extensions located in
>> various areas around Greater Vancouver.
>
>> We have a Cisco gateway we interface with
>> for PSTN access.
>
> The Cisco gateways (PGW?) are essentially commercial, not telco grade.
Cisco 3640 w/NM-HDV-1T1. But they'll handle some pretty heavy loads.
Maybe not Passport type loads, but they'll handle a lot.
> Asterisk is aiming at that market, and it will certainly make a huge
> dent in it.
Yep. And good on them. It seems well suited to that market.
>
> PGW/CCM is aimed at the traditional MNCS/Meridian etc. PBX market.
>
>> We also have a DISA system that allows about 20 numbers
>> to reroute long distance through it. For our purposes, it works
>> great. But I think they really need to rewrite their SIP stack and
>> work on the H.323 stack. As it is, they are significant weak points
>> (IMO).
>
> Not familiar with DISA, so can't comment.
AKA Dial-around. Dial a local DID and are presented with a new dialtone,
then dial LD number.
>>
>> Please note that all the comments above are based on my experiences
>> with said products. Your milage may vary.
>
> Asterisk has a huge future in front of it, but as you say, it will not
> be the only play. For the IP Centrex environment, it has the added
> advantage that IAX works very well through NAT firewalls, however, to
> interface into a larger-scale network, you'd want to see eg., SER
> running SIP applications for whatever you wanted/needed, and at least,
> to provide connectivity between your Asterisk instances. In
> particular, SIP allows you to separate the signalling and media, which
> provides for a far more resilient network design.
>
Seperate signalling and media also allows the DSP cards in gateways to
present different IPs than the call controller.
But I agree: Asterisk has huge potential. I'm very pleased with it in our
application. I'd love to see it improve significantly. Having used both
Cisco CallManager and Asterisk, I'll take Asterisk any day.
But if I'm tasked with switching carrier traffic, I'll use the Sansay or
GnuGK.
I definitely think this is a semantic difference. Asterisk is a great
commercial PBX. It probably makes a good gateway (I _only_ use it with
SIP, so I don't know). But it's still not telecom, at least not how I
understand telecom.
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