SUA on-link cb?
laforge at gnumonks.org
Mon Apr 4 18:19:39 UTC 2016
Dear Neels and others,
I was confused earlier today.
N-CONNECT is a primitive for a connection oriented SCCP-layer
connection. You receive it at each time a UE establishes a
connection-oriented SCCP for signalling, and it is what carrie RANAP
InitialUE and related messages.
What you are talking about for the RANAP Reset is the establishment of a
signalling link (underneath SCCP/SUA), so something like the SCTP
connection being established and released underneath.
In the SUA RFC 3868 there are:
* M-SCTP_ESTABLISH confirm
ASP confirms to LM that it has established an SCTP association with its peer
* M-SCTP_ESTABLISH indication
SUA informs LM that a remote ASP has established an SCTP association.
"LM" is the "Layer Manager". This is not the SCCP user, so no luck
However, Q.711 / Q.714 contain a N-STATE.indication, which can be sent
to a local SCCP user to inform it about the subsystem status.
"The local broadcast procedure provides a mechanism to inform local
allowed concerned subsystems of any related SCCP/subsystem/signalling
point status information received. [...] SCCP management then informs
local allowed concerned SCCP subsystems about the subsystem status by
invoking N-STATE indication primitive with "User-out-of-service"
So once we loose the signalling link, all SCCP users should receive
N-STATE.ind with "User-out-of-service".
When the signalling link is (re-)established, all SCCP users should
receive N-STATE.ind with "User-in-service". This should then be the
trigger to send a N-UNITDATA.req() with a RANAP Reset inside.
- Harald Welte <laforge at gnumonks.org> http://laforge.gnumonks.org/
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