Re: MTP3 Retstart in SUA

amrita.garg,

[email protected] wrote:                                   (Fri, 16 Dec 2005 15:07:42)
> Hi,
> 
> 
> When a MTP3 restart is over, SCCP sends a N-PCSTATE, N-STATE primitives
> informing "signaling point accessible", "remote SCCP accessible" and
> "users in service for subsystem". SUA at SG receives these primitives
> via NIF(nodal interworking function) and sends DAVA/DRST messages to
> concerned ASPs. 

I think you have that backward.  MTP3 indicates inaccessible point codes
after MTP Restart, not accessble ones.  The assumption being that after
MTP Restart, more nodes in the network will be available than
unavailable.

> What happens at SUA, when a SG discovers SS7 network isolation, when a
> MTP3 restart begins? Does SUA receive a N-PCSTATE(pointcode
> inaccessible), N-STATE(UOS) primitive. How does SUA know when to send a
> DUNA message.
> 
> What primitives are exchanged between MTP3, SCCP, NIF and SUA when MTP3
> restart begins.

How MTP3 indicates the beginning and end of MTP restart to SCCP is
implementation dependent (there is no primitive for it).  See Q.700.
Whatever the form of the indication the SCCP gets at the SG, an SGP can
indicate partial or complete isolation using the unsolicited ASP
Inactive Ack and unsolicited ASP Down Ack messages.  Such an unsolicited
message will cause the ASP to send ASP Active or ASP Up, in which case,
the SGP can respond with ERR("Management Blocking") until the isolation
clears.

--brian

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