RE: M3UA notify message

If there is consensus about using global-AS state for traffic mode related
procedures, we better have some explanation about it. IMHO, the way it is
stated right now in the RFC/IG does hardly lead to that interpretation -I am
speaking of section 4.3 -.

   Thanks,
   Tolga




> -----Original Message-----
> From: Haresign Lincoln [mailto:[email protected]]
> Sent: Thursday, February 23, 2006 10:20 AM
> To: nitin; [email protected]; [email protected]
> Cc: [email protected]
> Subject: RE: [Sigtran] M3UA notify message
>
>
> Nitin,
>
> For the first scenario, I would think that the ASP is either:
>
> 1) Configured at the SG (perhaps with IP addresses)
> 2) Is sending an ASPID to the SG.
>
> In this way, the SG can see that the ASUP/ACPAC are coming from the same
> ASP as the ASPID MUST be unique within the AS.  Therefore, the SG
> properly manages the state of the AS and ASP.
>
> For the second scenario, I would say the data message should be dropped
> and an error return since the ASP/SGP2 state machine has not been
> properly completed.
>
> For scenario three, once one ASP is active to one SGP, the AS is active.
>
> Regards,
> Lincoln
>
> ________________________________
>
> From: nitin [mailto:[email protected]]
> Sent: Thursday, February 23, 2006 9:40 AM
> To: [email protected]; [email protected]
> Cc: [email protected]
> Subject: Re: [Sigtran] M3UA notify message
>
>
>
>
>
> I am explaining some scenarios :-
>
> 1. Consider SG consisting of SGP1 and SGP2.
>      Suppose an AS contain one ASP and the traffic mode of AS is
> override.
>      If we look in terms of SGP then this override mode
>      is of no use, but if we look in terms of SG  and this ASP is making
> associations with
>      two SGP then this is of much significance. Actually for SGP , ASP
> is identified by
>      the sctp association . For even if there is only one ASP in AS but
> for SGP's they
>      don't know this ASP as single ASP.
>
>         Please take AS as inactive initially on both SGP's.
>
>      ASP               SGP1              SGP2       SG
>       |     aspAc       |                 |          |
>       |---------------->|                 |          | ( please note
> here that i have drawn  notify from SG,
>       |<----------------|                 |          |   just to
> highlight that state of AS is maintained at SG,
>       |  asp ac ack     |                 |          |             so
> logically this notify is sent with respect to SG)
>       |<---------------------------------------------|
>       |       notify AS active            |          |
>       |                 |                 |          |
>       |---aspAc-------------------------->|          |
>       |       aspac ack |                 |          |
>       |<----------------------------------|          |
>       |         notify Alt. Asp Ac.       |          |
>       |<---------------------------------------------|
>       |                 |                 |          |
>       |                 |                 |          |
>
>  Now sicne  when we have configured AS at the SG, we have configured
> that AS has only one SGP
>  in override mode. However this override mode doesn't makes sense with
> one ASP in AS.
>
>  But here what is happening that SGP's doesnot know , that it is the
> same ASP which is doing
>  active with both SGP's. So when ASP  does active with SGP1 then AS
> becomes active. Now when
>  ASP does active with SGP2 this is new ASP for SGP2. So what should be
> done in this case.Should
>  Alternate ASP active notify be sent in this case to same ASP .
>
> 2. Now consider another case.
>
>    In this scenario , ASP1 and ASP2 are both part of AS and SGP1 and
> SGP2 are both part of SG1.
>    In this case assume that ASP1 and ASP2 are both inactive at their
> respective SGP's.
>    Now my question is little bit different in this case as explained
> below:-
>
>      ASP1                 ASP2                SGP1           SGP2
>       |     aspAc           |                   |              |
>       |---------------------------------------->|              |
>
>       |<----------------------------------------|              |
>       |  asp ac ack         |                   |              |
>
>       |<--------------------------------|                        |
>       |       notify AS active                   |
> |
>       |                          |                        |
> |
>       |                                    data        |
> |
>                                 |---------------------------------->
>       |                         |                        |
> |
>       |                          |                        |
>
>       |                      |                       |
>       |
> |
>       |                          |                        |
> |
>       |                          |                        |
> |
>
>
> Should this data message be dropped at SG or should it be allowed to SS7
> side , Since AS is active at SG
>  but ASP2 is not active on SGP2.
>
> 3. Now here is the 3rd scenario , this is related to n+k AS.
>
> In this case , configuration is AS consisting of ASP1 and ASP2.
> SG consisting of SGP1 and SGP2.
> Obviously the traffic mode is loadshare.
> Now only ASP1 is doing ASP active on SGP1 and SGP2.
> ASP2 has not done any m3ua procedures with neither SGP1 , nor SGP2.
>
> ASP1                 ASP2                SGP1           SGP2
>       |     aspAc           |                        |
> |
>       |--------------------------------->|                      |
>
>       |<---------------------------------|                      |
>
>       |  asp ac ack       |                        |
> |
>       |                          |                        |
>       |                          |                        |
>       |                          |                        |
> |
>       |----------asp Ac.---------------------------------------->|
>
>       <-----------ASP act . ack--------------------------------------- |
>       |                          |                        |
>
>       |<----------------------------------------------------|
>       |
> |
>       |                          |                        |
> |
>       |                          |                        |
> |
>
> Now since ASP1 has done active on both SGP1 and SGP2 , it is active on
> two SGP's.
> So with respect to SG two SGP's are active. Should in this case AS be
> active or not.
>
> thanks
> nitin
>
> ----- Original Message -----
> From: "Brian F. G. Bidulock" <[email protected]>
> To: <[email protected]>
> Cc: <[email protected]>
> Sent: Thursday, February 23, 2006 11:34 AM
> Subject: Re: [Sigtran] M3UA notify message
>
> > Prabind,
> >
> > You are correct, there is a case where the ASP state is shared across
> > the SGPs making up an SG: in the Override traffic mode AS it is
> > necessary to share which ASP is "Active" and which is "Standby" as
> only
> > one ASP can be Active for the AS.
> >
> > This is also a case where state transitions directly associated with
> > ASPTM/ASPSM message procedures must be considered on an SG-wide basis,
> > contrary to Tolga's previous statements on this thread.
> >
> > It is possible, but perhaps less important to interoperability, that
> an
> > SG could coordinate the ASP state for ASPs in a Loadshare or Broadcast
> > AS.  That is, when loadsharing, the selection algorithm at an SGP
> could
> > consider the availability of ASPs to other SGPs to more equally
> > distribute traffic.  For Broadcast mode AS, consideration of ASP state
> > across the SGP could provide a more optimal broadcast of traffic (i.e.
> > without sending multiple messages to or missing completely an ASP).
> >
> > For the case of SSNM, it is possible (but not required) for the SG to
> > avoid sending duplicate SSNM messagese to any given ASP.  By
> considering
> > the ASP state on an SG-wide basis, it is possible to ensure that only
> > one SSNM message is sent to an ASP (via only one SGP).
> >
> > The override and SSNM cases were given consideration in the original
> > thread that led to the wording 1.4.1.  The others were not so much.
> >
> > Therefore, I agree that the statement in 1.4.1 should not be ammended.
> >
> > --brian
> >
> >
> > [email protected] wrote:                (Thu, 23 Feb 2006
> 09:50:04)
> > >
> > > I am still concerned about this statement from Tolga:
> > >
> > > " In any case, it is good that there is finally consensus regarding
> that
> > > ASPSM/ASPTM procedures and associated state machines being
> independent
> > > on
> > > each SGP."
> > >
> > > If multiple SGPs are serving a single AS, then shouldn't the ASP
> states
> > > also be shared across the related SGPs?
> > > Else if I am wrong then the following statement in section 1.4.1
> should
> > > be amended to share the AS states only.
> > > " Where an SG contains more than one SGP, the MTP3 routeset, SPMC
> and
> > >    remote AS/ASP states of each SGP SHOULD be coordinated across all
> the
> > >    SGPs."
> > >
> > > Tolga, further considering the sahring of ASP states then, in the
> case
> > > of the interoperability issue (as you depicted), the rfc says that
> if an
> > > ASP is already inactive the ASP-UP message would still be respnded
> by an
> > > ack.
> > >
> > > I think the things become simpler if we consider sharing of ASP
> states
> > > of a particular AS across all SGPs serving that AS.
> > >
> > >
> > > Regards,
> > >
> > > Prabind
> > >
> >
> > --
> > Brian F. G. Bidulock
> > [email protected]
> > http://www.openss7.org/
> >
> > _______________________________________________
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> >
> >
> >
> >
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