Re: Multiple SUA SGs, sending for SSP from SGs

Tolga,

Tolga Asveren wrote:                            (Tue, 10 Jan 2006 17:08:40)
>
> Ah O.K., I forget for a while the "undocumented" relaying functionality of
> SUA :-)
> 
> In any case, personally I don't see how it may be usefull for multiple SG
> scenario because SCCPs are locally hosted in SGs. Relaying messages is a
> different story.

SCCPs are only locally hosted at an SG in the pure backhaul case.  In
the multiple SG as STP scenario, and in the SCCP relay scenario, SCCPs
can also be hosted at the ASP or IPSP.

M3UA is not so different.  MTPs can be locally hosted at the ASP in the
multiple SG as STP scenario.  It was always the intention for M3UA to
support this scenario.

E.g, section 1.3.2 of RFC 3332:

  ... However, in the case where an ASP is connected to more than one
  SG, the M3UA layer at an ASP should maintain the status of configured
  SS7 destinations and route messages according to the availability and
  congestion status of the routes to these destinations via each SG.

Also see Section 1.4.1 and Figure 1.  See also, Figure 5 in the
Appendix, Appendix A.2.2.  There are additional passages throughout the
document.

In fact, this is the sole purpose of the DRST message: see section
3.4.6.

SUA simply provides the additional mechanism (as does SCCP) of managing
the availability of SCCP User across such an arrangement.  M3UA provides
only partial MTP User availabilty (DUPU) management, as does MTP3 (UPU).

These are fundamental capabilities required to meet the objective of
providing transparent interworking to the SS7 network.

--brian

-- 
Brian F. G. Bidulock
[email protected]
http://www.openss7.org/