Subject: RE: [SUA issue 17] IPSP cases.

From: [email-masked]
Date: Tue, 28 Aug 2001 12:10:56 +0300

Hi Brian,

> Which IPSP sends APSUP?  

Which ever one wants to.

> What happens if both IPSPs sends ASPUP?

Then you may get 2 SUA 'associations' - if this is
being done within a single operator network, it can
be handled as a network management issue.  

> When one IPSP sends ASPAC for an RC does it activate it for both
> IPSPs?  Or, does the other IPSP need to send ASPAC as well?  

I have always thought it is then active for both.  By accepting
the ASPAC, the recieving IPSP is implicitly accepting the RC.

> When CO messages are exchanged, how does the receiving IPSP indicate
> protocol specific error conditions to the other IPSP?  (i.e, those
> which are provided peer-to-peer by the ER message in SCCP?).

COERR message.

> Is there any coupling of connection sections between IPSP?  

I haven't seen a requirement for coupling of connection sections.

> Does an IPSP ever act as a relay point?  As an SCCP relay?  As an MTP
> relay?  

As per SUA v7, no.  The SUA relay has not been well defined, as I 
understand it was something that Gery supported & we agreed that 
we should allow it, but not detail how it can be used.  Its use
could be specified in an extension draft.  It does not act as
an SCCP relay nor an MTP relay.

> What is the role of the AMF for IPSPs?  Does the AMF sit
> above or below the SCCP/SCCP-User interface?  

Below the use interface.  AMF is a function that SUA can use,
is somewhat analagous to GTT.  

> Does an IPSP provide an SCCP/SCCP-User interface to local SCCP-Users?  

Yes, just as an ASP would.

> Does an IPSP need to support multipled associations and multiple 
> routing contexts between IPSPs?  

No, but it may.  Implementation specific.

> What parts of the SCCP state machines must be implemented at the 
> IPSP?  

Enough to ensure proper working of the IPSP.

> Can an SG be both an SGP and an IPSP?

Anything is possible, but I probably wouldn't recommend this 
kind of configuration.  
 
====

Some things that I think could be better specified:

IPSP -> provides a user interface.  Does not provide relay functionality

SUA Relay Point -> does not provide a user interface. Does provide relay
functionality.

John

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