<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;"><div class="plainMail"><pre>>On Fri, Mar 16, 2012 at 12:37 PM, Marcelo Pacheco <<a href="http://lists.digium.com/mailman/listinfo/asterisk-ss7">marcelo at m2j.com.br</a>>wrote:
><i>> Gustavo,
</i>>><i>
</i>><i>> I think you're confusing the general function of an STP with the external
</i>><i>> signaling network architecture used by ANSI countries.
</i>>><i>
</i>><i>> All incumbent networks in Brazil make heavy usage of STPs.
</i>><i>> They have lots of
</i>>><i>
</i>>TDM switches, and to avoid a full mesh of signaling links between all TDM
><i>> switches that have voice trunks between them, STPs are used to aggregate
</i>><i>>SS7 traffic.
</i>><i>
</i>
>STP is single point of failure unless used in pairs; using STP pairs
>requires combined linkset - does ITU have this capability? don't think so
>- SLS is only 4 bits; it's 5 bits in ANSI
>of course it is what it is - but i'm curious how the fault tolerance vs
>management ease balance out - mildly curious
><i>
</i>><i>> Also STPs are also used as billing entities and for resolving LNP in some
</i>><i>> carriers.
</i>>><i>
</i>><i>> This seems to me to be the motivation for using STPs.
</i>
><i> >I'm pretty sure STPs have lots of usage in other ITU countries.
</i>><i>
</i>><i>> Poland. "Lots" is a relative term. You do see them. Seems like they were
</i>>being introduced about the same time that VoIP was coming in too. Now
>what? Keep building TDM or cap it and go to VoIP? I think we all know how
>that is turning out.
><i>> However they don't have a fully separate signaling network, 64kbps SS7
</i>><i>> links make maximum usage of semi permanent call setups, specially for
</i>><i>> interconnects with other carriers (using bearer channels of existing E1
</i>><i>> voice trunks).
</i>>><i>
</i>><i>> However competitive carriers use redundant soft switch architecture don't
</i>><i>> need STPs, since signaling flows through the IP network, without explicit
</i>><i>> signaling channels.
</i>><i>
</i>><i>>I fell more important than the capability of Asterisk performing as an
</i>><i>> STP, is much more important full linkset functionality as a regular
</i>><i>> signaling point. For instance, the following scenario can't be implemented
</i>><i>> with libss7 today:
</i>>><i>
</i>><i>> Asterisk --x-- STP A ---x--- Switch1,2,3,4,5,6,7,8
</i>><i>> STP B
</i>>><i>
</i>><i>> Where Asterisk has voice CICs with all 8 switches, and all signaling needs
</i>><i>> to be shared across a pair of signaling links, one with each STP. Specially
</i>><i>> with E1s with all 8 switches can't fit on a single Asterisk box.
</i>>><i>
</i>
>Are you describing the combined linkset? When I've seen things like this
>in ITU networks, A was primary and B was alternate (used when A was not
>available), instead of the ANSI model where A and B are peers and normally
>used equally using a 5 bit SLS.<br><br>Hi <br>you can use one of SLS 4Bits for loadsharing between 2 Linksets to 2 STPs(you still can have 2x8 signaling links)<br>if a ITU network needs 4 STPs they can use 2 bits for Linkset loadsharing or in every LX divide trunkgroups to two parts and for one part set STP1,2=>priority=1 STP3,4=priority=2 <br>and other part vice versa.
<br>Regards<br>M.Shirazi <br> </pre></div></td></tr></table>