Subject: [Sigtran] Use of Traffic Mode Type

From: "vaibhav_madan" <[email-masked]>
Date: Tue, 12 Feb 2002 17:24:11 +0530

Hi

        Can someone please explain the usage of Traffic Mode Type in the Asp Active Ack message? In the M3UA draft, it is given that the SGP will return an error(Reason:Invalid Traffic Mode Type) if we try to make an ASP Active within an AS in a Traffic Mode Type which is different from the already existing Traffic Mode Type for that AS. Say AS-1 has Traffic Mode Type Loadshare and we try to make an ASP active within AS-1 in Traffic Mode Override.

       So if the Traffic Mode Type in the ASP Active Ack is always going to be the same as the one sent in ASP Active message, then why is it needed there? I am sure I am missing something. Can someone please shed some light on it?

Regards

Vaibhav
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---

From: "Sundaresan M" <[email-masked]>
Date: Tue, 12 Feb 2002 19:01:50 +0530

Hi Vaibhav,

Normally Traffic Mode Type (Loadshare or Override or Broadcast) of an AS
will either be configured at the SG side or will be taken from the traffic
handling mode in the first ASP-Active Message recieved from the AS. Later on
SG will expect Active messages with valid Routing Contexts and the same
Traffic Handling Mode from the ASP's in that AS.

This is a reference from
http://www.ietf.org/internet-drafts/draft-ietf-sigtran-m3ua-12.txt
Section 4.3.4.3 ASP Active Procedures
/*****
There are three modes of Application Server traffic handling in the SGP
M3UA layer: Override, Loadshare and Broadcast.  When included, the
Traffic Mode Type parameter in the ASP Active message indicates the
traffic handling mode to be used in a particular Application Server.
If the SGP determines that the mode indicated in an ASP Active
message is unsupported or incompatible with the mode currently
configured for the AS, the SGP responds with an Error message
("Unsupported / Invalid Traffic Handling Mode").  If the traffic
handling mode of the Application Server is not already known via
configuration data, then the traffic handling mode indicated in the
first ASP Active message causing the transition of the Application
Server state to AS-ACTIVE MAY be used to set the mode. *****/

Basically, if the ASP in a Particular AS sends a ASP Active Mesage with a
fraud Traffic Mode type then SG has to reply him with Errormessage and can
abort the Association if required.

Asp Active Ack is an acknowledgement sent from SG to ASP confirming the
acceptance of the Active message and it also informs ASP that from now on it
can start sending and receiving traffic from SG. Also if multiple Routing
Contexts(RC) are sent in a Active message. SG can inform which RC's are
acepted for Traffic (through ASP ACTIVE) and which RC's are invalid(through
ERROR,invalid RC).

Draft-12.txt
Reference for the above :
By sending an ASP
Active Ack message, the SGP or IPSP is now ready to receive and
send traffic for the related Routing Context(s).  The ASP SHOULD
NOT send Data or SSNM messages for the related Routing Context(s)
before receiving an ASP Active Ack message, or it will risk message
loss.

Multiple ASP Active Ack messages MAY be used in response to an ASP
Active message containing multiple Routing Contexts, allowing the SGP
or IPSP to independently acknowledge the ASP Active message for
different (sets of) Routing Contexts.  The SGP or IPSP MUST send an
Error message ("Invalid Routing Context") for each Routing Context
value that the ASP cannot be successfully activated .

Hope this helps you,
Best Regards,
Sundar.
Future Software Communications

  -----Original Message-----
  From: [email-masked] [mailto:[email-masked]]On Behalf Of
vaibhav_madan
  Sent: Tuesday, 12 February 2002 5:24 PM
  To: [email-masked]
  Subject: [Sigtran] Use of Traffic Mode Type

  Hi

          Can someone please explain the usage of Traffic Mode Type in the
Asp Active Ack message? In the M3UA draft, it is given that the SGP will
return an error(Reason:Invalid Traffic Mode Type) if we try to make an ASP
Active within an AS in a Traffic Mode Type which is different from the
already existing Traffic Mode Type for that AS. Say AS-1 has Traffic Mode
Type Loadshare and we try to make an ASP active within AS-1 in Traffic Mode
Override.

         So if the Traffic Mode Type in the ASP Active Ack is always going
to be the same as the one sent in ASP Active message, then why is it needed
there? I am sure I am missing something. Can someone please shed some light
on it?

  Regards

  Vaibhav

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