RE: Recommendation for SUA modifications

Brian,

Are you saying that an ASP can not congest?  I'm not really sure where
you are going with this.  The RFC says the following:

   The SUA layer at an ASP or IPSP MAY indicate local congestion to an
   SUA peer with an SCON message.  When an SG receives a congestion
   message (SCON) from an ASP, and the SG determines that an endpoint is
   now encountering congestion, it MAY trigger congestion procedures of
   the relevant SCCP standard.

If this is not true, let me know and we will need to amend the RFC and
find another way to handle ASP congestion.  My very first email that
started this thread asked the question of whether SCON was valid from
ASP to SG.  At the time, you indicated that this was valid. Are you now
saying it is valid, but only in limited scenarios?

If this is valid, then there are two scenarios that the RFC does not
handle:

1) ASP shares the same point code as the SG and is not aware of it's
point code.  Meaning the ASP may just be a global title.  Or there could
be multiple AS behind the SG with different subsystems but sharing the
same point code as the SG.

2) ASP is multiple point codes.

In the RFC, the handling of the SCON message by the SG is implementation
dependent.

Regards,
Lincoln


-----Original Message-----
From: Brian F. G. Bidulock [mailto:[email protected]] 
Sent: Friday, October 14, 2005 8:36 AM
To: Haresign Lincoln
Cc: Valerie Gastaud; [email protected]; [email protected];
[email protected]
Subject: Re: [Sigtran] Recommendation for SUA modifications

Lincoln,

The RFC does not say otherwise:

3.10.24.  Congestion Level

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Tag = 0x0118          |             Length = 8        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Congestion Level                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Congestion Level field: 8-bits (unsigned integer)

   The Congestion Level field contains the level at which congestion has
   occurred.

   When the Congestion Level parameter is included in a SCON message
   that corresponds to an N-PCSTATE primitive, the Congestion Level
   field indicates the MTP congestion level experienced by the local or
   affected signalling point as indicated by the Affected Point Code(s)
   also in the SCON message.  In this case, valid values for the
   Congestion Level field are as follows:

      0  No Congestion or Undefined
      1  Congestion Level 1
      2  Congestion Level 2
      3  Congestion Level 3


   When the Congestion Level parameter is included in a SCON message
   that corresponds to an N-STATE primitive, the Congestion Level field
   indicates the SCCP restricted importance level experienced by the
   local or affected subsystem as indicated by the Affected Point Code
   and Subsystem Number also in the SCON message. In this case, valid
   values for the Congestion Level field range from 0 to 7, where 0
   indicates the least congested and 7 indicates the most congested
   subsystem.

--brian

Haresign Lincoln wrote:                     (Fri, 14 Oct 2005 08:33:18)
> Brian,
> 
> That's your definition.  The RFC says otherwise.
> 
> An ASP can congest according to the RFC and according to practical 
> matters in networks.  We need a mechanism to support ASP congestion.
> The RFC has specified one.  A minor change to the RFC allows the cases

> that the current RFC has not covered.
> 
> And it has no impact on existing SGs since the handling of an SCON is 
> optional.
> 
> Regards,
> Lincoln
> 
> 
> -----Original Message-----
> From: Brian F. G. Bidulock [mailto:[email protected]]
> Sent: Friday, October 14, 2005 8:28 AM
> To: Haresign Lincoln
> Cc: Valerie Gastaud; [email protected]; [email protected]; 
> [email protected]
> Subject: Re: [Sigtran] Recommendation for SUA modifications
> 
> Lincoln,
> 
> The congestion level only applies to a single point code.  SCCP 
> maintains a independent congestion level for each point code.
> 
> --brian
> 
> Haresign Lincoln wrote:                        (Fri, 14 Oct 2005
> 08:19:02)
> > Valerie,
> > 
> > I think this is a good solution.  Using the RC also addresses the 
> > scenario of the ASP supporting multiple point codes (not something 
> > that we do, but the RFC supports it).  Since the current SCON 
> > message doesn't indicate that multiple point codes can be specified 
> > in the SCON, the RC parameter would handle this scenario also.
> > 
> > Regards,
> > Lincoln
> > 
> 
> --
> Brian F. G. Bidulock
> [email protected]
> http://www.openss7.org/
> 
> ______________________________________________________________________
>   This email message has been scanned by PineApp Mail-Secure and has 
> been found clean.
> 

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

______________________________________________________________________
  This email message has been scanned by PineApp Mail-Secure and has
been found clean.