[Serusers] why combine ser with asterisk
Greger V. Teigre
greger at teigre.com
Sun Aug 26 09:28:42 CEST 2007
I don't like all this cross-posting, so I have removed the other lists.
My comments will be from iptel.org perspective.
Inline.
Fredrik Lundmark wrote:
> Hmm,
>
> I find the dialog I initiated both amusing and (for me) very
> informative. Being pretty new to these lists, I'm evaluating
> technology to use for an ITSP setup and I'll welcome more comments and
> views as the ones below - they help me understand "what to use for
> which purpose".
>
> What my needs are:
>
> 1. Prepaid support - maybe I don't need a b2bua, could the dialogue
> module be "call-aware" and be used to terminate calls upon
> "end-of-credits"?
>
Either you need a b2bua where you also proxy the rtp stream or you need
to accept that you get "hung" calls (i.e. BYEs never hitting your box)
due to various reasons, for example UA power failure.
OpenSER has dialog-statefulness like the one you are looking for.
iptel.org users tend to lean towards: it's a telco-problem, fix it in
the telco-world (using ex. Session-Timers or timing the PSTN calls in
the gateways) or go the full line, use a b2bua.
I believe there's a calling card app in sems that you can use/adapt.
>
> 1. Filtering of Refer & Replace (RFCs 3515, 3891, 3892), replacing
> them with Re-Inivtes - to support most UAs, at the same being
> compliant with SIP trunks supporting SIPConnect
>
Now, for this you "need" a b2bua to be compliant in all scenarios. I
know some people have successfully caught 302s from UAs, then instead of
sending the reply back, append a branch with the ruri in the Diversion
header.
Doing more than that is generally considered "fixing broken UAs" and the
general advice is "don't support it". You are quickly getting yourself
into a situation where supporting 2% of your user base, takes 80% of
your maintenance costs.
>
> 1. IVR capability - i.e. "regular IVR" (customized stuff) as well
> as standard applications (voicemail, conference)
>
Here people split between asterisk, sems, and commercial. Sems can do
some simple stuff right out of the box, but you will probably have to do
some coding for what you need. Asterisk is more likely to give you more
out of the box, but if you still need adaptation, you will find it more
time-consuming adapting asterisk.
>
> 1. Queuing of calls
>
Well, as in "please hold, we will pick up the call whenever we feel like
it" ?
This is a pbx or a call center application.
>
> 1. 3pcc - capability for handling calls from a operator's application
>
Simple 3pcc can be done in SER, while many/most call flows require a
b2bua. SEMS gives you quite a lot of power, but I have no experience in
using sems in this area. You should probably look at what IETF BLISS
working group is doing.
> Anyone wanting to advise?
I hope it helps.
g-)
>
> BR///
>
> Fredrik
>
>
> ----- Original Message -----
> *From:* Greger V. Teigre <mailto:greger at teigre.com>
> *To:* SIP <mailto:sip at arcdiv.com>
> *Cc:* Fredrik Lundmark <mailto:fredrik at dimi.se> ;
> serusers at lists.iptel.org <mailto:serusers at lists.iptel.org>
> *Sent:* Friday, August 24, 2007 9:27 AM
> *Subject:* Re: [Serusers] why combine ser with asterisk
>
> Hm, I don't agree with that comparison ;-)
> Asterisk is a PBX, SEMS is a platform for specific applications. There
> are some common pre-developed applications that easily can be set up
> (like a conference bridge, play announcements etc). However, if you
> need a PBX with lots of features, you don't start with SEMS.
>
> I would rather compare Asterisk to a pick-up truck and SEMS to the
> Porsche. Use the truck for pretty much any work, but the Porsche is
> made for speed... :-)
>
> Using Asterisk as only a conference bridge and playing announcements
> is like using the pick-up truck to move your 12-piece china...
> g-)
>
> SIP wrote:
>> Offers them? Yes. Offers them in a clean, friendly, usable package? Not
>> so much yet.
>>
>> SEMS has raw capability, but if you want it to do many of the things
>> Asterisk can do, you need to know how to code that yourself, or you're
>> going to be digging about the code for documentation on features (since
>> the current docs are not the world's greatest).
>>
>> Don't get me wrong, SEMS has its place, and is a constantly evolving
>> work of art (we use SEMS for several things in our environment), but
>> comparing SEMS to Asterisk is a bit like comparing a bunch of car parts
>> to a Porsche.
>>
>> N.
>>
>>
>> Fredrik Lundmark wrote:
>>
>>> I'm still learning myself, but SEMS (iptel.org/sems) seems to offer
>>> many of the media- and/or b2bua-functions that Asterisk do.
>>>
>>> ///Fredrik
>>>
>>>
>>>
>>> ----- Original Message ----- From: "SIP" <sip at arcdiv.com>
>>> To: "Nhadie" <nhadie at tbgi.net.ph>
>>> Cc: <asterisk-users at lists.digium.com>; <serusers at lists.iptel.org>
>>> Sent: Thursday, August 23, 2007 1:38 PM
>>> Subject: Re: [Serusers] why combine ser with asterisk
>>>
>>>
>>>
>>>> Asterisk is an excellent PBX system, and makes a very good endpoint in
>>>> the SIP chain for all sorts of things -- IVR systems, voicemail
>>>> applications, automated messages, etc.
>>>>
>>>> It has an extremely well-written CDR engine, so many people mesh it with
>>>> billing applications to produce accurate accounting information. It also
>>>> is fully aware of the media stream, which means it's capable of cutting
>>>> off a call mid-stream, injecting audio into the call, etc, etc.
>>>>
>>>> Programming for Asterisk addons can be easily done in just about any
>>>> language, and it meshes well with the overall structure. Programming for
>>>> SER is... not so simple.
>>>>
>>>> As for running them both on the same box, the biggest problem would be
>>>> resources. Unlike SER, Asterisk is not designed to be a carrier-grade
>>>> SIP proxy. If you're actually proxying the media stream, you'd be
>>>> hard-pressed to squeeze more than 150 simultaneous calls out of Asterisk
>>>> on even the beefiest of hardware. Add SER to the same box, and you will
>>>> quickly run into resource problems in medium-sized environments. It also
>>>> doesn't have a lot of the SIP proxy functionality that SER has.
>>>>
>>>> If you're careful, you can configure Asterisk NOT to handle the media
>>>> stream and still use it for prepaid solutions (using astcc or
>>>> asterisk-b2bua), and this will save you bandwidth (but you'll still
>>>> likely run into NAT issues that need to be dealt with somehow) and still
>>>> let you use Asterisk as an in-between point.
>>>>
>>>> Together, Asterisk and SER make a very powerful combination for
>>>> providing a full suite of services to clientele, and each plays well off
>>>> the other's strengths.
>>>>
>>>> N.
>>>>
>>>>
>>>>
>>>> Nhadie wrote:
>>>>
>>>>> Hi All,
>>>>>
>>>>> What's the advantage of combining ser with asterisk? I always see
>>>>> comments like using ser with asterisk is a very good solution etc. etc.
>>>>> the thing i liked with ser is that it does not do codec translation,
>>>>> which saves me cpu usage and also bandwidth. if i combine it with
>>>>> asterisk, would it not use codec translation?
>>>>>
>>>>> i also read that there is also a problem when ser and asterisk is
>>>>> run on
>>>>> the same machine, why is it so?
>>>>> if use prepaid billing solution for asterisk like astcc, would i
>>>>> then be
>>>>> able to provide prepaid service?
>>>>>
>>>>> soryy for asking too much, i'd just like to really understand it. Thank
>>>>> You in advanced.
>>>>>
>>>>> Regards,
>>>>> Nhadie
>>>>> _______________________________________________
>>>>> Serusers mailing list
>>>>> Serusers at lists.iptel.org
>>>>> http://lists.iptel.org/mailman/listinfo/serusers
>>>>>
>>>>>
>>>> _______________________________________________
>>>> Serusers mailing list
>>>> Serusers at lists.iptel.org
>>>> http://lists.iptel.org/mailman/listinfo/serusers
>>>>
>>>>
>>
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>>
>>
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