[asterisk-ss7] Asterisk like a SS7 STP
Marcelo Pacheco
marcelo at m2j.com.br
Fri Mar 16 11:37:57 CDT 2012
Gustavo,
I think you're confusing the general function of an STP with the
external signaling network architecture used by ANSI countries.
All incumbent networks in Brazil make heavy usage of STPs.
They have lots of TDM switches, and to avoid a full mesh of signaling
links between all TDM switches that have voice trunks between them, STPs
are used to aggregate SS7 traffic.
Also STPs are also used as billing entities and for resolving LNP in
some carriers.
I'm pretty sure STPs have lots of usage in other ITU countries.
However they don't have a fully separate signaling network, 64kbps SS7
links make maximum usage of semi permanent call setups, specially for
interconnects with other carriers (using bearer channels of existing E1
voice trunks).
However competitive carriers use redundant soft switch architecture
don't need STPs, since signaling flows through the IP network, without
explicit signaling channels.
I fell more important than the capability of Asterisk performing as an
STP, is much more important full linkset functionality as a regular
signaling point. For instance, the following scenario can't be
implemented with libss7 today:
Asterisk --x-- STP A ---x--- Switch1,2,3,4,5,6,7,8
STP B
Where Asterisk has voice CICs with all 8 switches, and all signaling
needs to be shared across a pair of signaling links, one with each STP.
Specially with E1s with all 8 switches can't fit on a single Asterisk box.
Marcelo Pacheco
On 03/15/12 14:39, Gustavo Mársico wrote:
>
> On Mar 15, 2012, at 2:17 PM, Michael Mueller wrote:
>
>> STPs in ITU-land are awkward since ITU voice networks are a mesh of
>> E1 with signaling in the same bundles as the voice
>>
>> in ANSI-land, the STP was incorporated and mandated by two large and
>> powerful monopolies: BC and ATT; signaling became de-coupled from the
>> voice and traveling in a separate network connected by hierarchy of
>> mated pair STPs
>>
>> putting an STP or an STP-like invention in an typical ITU network
>> raises questions about commercial viability: having a central STP
>> might raise your E1 charges because they travel over longer distances
>> - this raises monthly charges in many places; might be cheaper to
>> connect locally - but then you have increased monthly charges for
>> colo space
>>
>> there is conceptual dissonance between STPs and ITU networks - STPs
>> require the signaling be separate from the voice, and ITU mesh
>> networks are built around signaling and voice channels traveling in
>> the same bundles of wire (i've just restated my first 2 paragraphs);
>> decoupling signaling means using an entire E1 for a single signal
>> channel; this usually causes despair to the typical ITU ss7 engineer
>> but is business as usual to the ANSI counterpart
> This is not quite correct. CALA region mostly uses separate E1 for
> signalling and media when a STP is used. If STP is not required, some
> telco choose to separate and others don't. As the same as ANSI does.
> In fact, it's a matter of how the people wants to make it work.
>
>
>> the cheapest STP I know of is the PT Segway; maybe you can get a
>> Tekelec Eagle; I'm not aware of any Linux based DIY STPs; ss7box
>> started as an STP but evolved away from the function as there was
>> little need for a low-end STP in ANSI-land and zero need for it in
>> ITU-land
>>
>> ss7box supports Asterisk box clustering around a single point code
>> with CIC routing; clustering might be something you want to
>> investigate - you'd have to examine the technical, commercial, and
>> incumbent connection policies to see if it would help you build an IP
>> voice network with fewer connections to the incumbent telco network
>> using such a clustering function
>>
>> you asked a complicated question, or I've turned a simple question
>> into a complicated one - both are plausible
>>
>> On Thu, Mar 15, 2012 at 11:45 AM, Rodrigo Ricardo Passos
>> <rodrigopassos at gmail.com <mailto:rodrigopassos at gmail.com>> wrote:
>>
>> Michael,
>>
>> Can you explain more?
>> Here, in Brazil, the standard is ITU. I think it isn´t possible
>> because ITU is used in all telcos.
>>
>>
>> Em 15/03/2012 12:25, Michael Mueller escreveu:
>>> connecting a mated pair of STPs to an ANSI network as a peer has
>>> more requirements than connecting an SSP; ITU STP are less
>>> common so connection requirements might be more variable
>>>
>>> On Thu, Mar 15, 2012 at 10:19 AM, Rodrigo Ricardo Passos
>>> <rodrigopassos at gmail.com <mailto:rodrigopassos at gmail.com>> wrote:
>>>
>>> Gustavo,
>>>
>>> Do you know Yate? Knows if Yate can be used in place of
>>> asterisk?
>>> I know that this list is about Asterisk SS7, but I think
>>> that this question doesn´t bad.
>>>
>>> Regards,
>>>
>>> Rodrigo
>>>
>>> Em 14/03/2012 16:55, Gustavo Mársico escreveu:
>>>> There is no pure STP implementation on libss7 or chan_ss7.
>>>> Modules cannot send TFA, TFP, support STP timers,
>>>> etc. Today, all you can do is routing based in the
>>>> extensions, but that's not STP function.
>>>> However, I know that some efforts were made on libss7 and
>>>> the last time I checked looked promising. I'll try to find
>>>> what's going on there.
>>>>
>>>> Regards
>>>>
>>>> Gustavo
>>>>
>>>>
>>>> On Mar 14, 2012, at 4:39 PM, Rodrigo Ricardo Passos wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> I have a question of how can I create STPs Boxes with
>>>>> Asterisk in my network?
>>>>>
>>>>> My project includes a creation of network with asterisk
>>>>> SPs and STPs and my initial idea is a implementation of
>>>>> these boxes using TDMoE. So, create two boxes like STP e
>>>>> another's boxes like SP.
>>>>>
>>>>> All signalization will pass to both STPs. Anyone knows if
>>>>> my scenario will be one scenario with a real STP boxes or
>>>>> this will never STP ambient?
>>>>>
>>>>> Other question is, if this last question is false, how can
>>>>> I create this ambient with asterisk?
>>>>>
>>>>>
>>>>> Best Regards,
>>>>>
>>>>> Rodrigo
>>>>>
>>>>>
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