Re: M3UA notify message

hi ,
For the 3rd case , i had not mentioned n , it is 2.
So if it is 2, then what will be the case.
----- Original Message ----- 
From: "Haresign Lincoln" <[email protected]>
To: "nitin" <[email protected]>; <[email protected]>;
<[email protected]>
Cc: <[email protected]>
Sent: Thursday, February 23, 2006 8:49 PM
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/
>
> _______________________________________________
> Sigtran mailing list
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> https://www1.ietf.org/mailman/listinfo/sigtran
>
>
>
>
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