Subject: Questions on MEGACO

From: Shalini Philip <[email-masked]>
Date: Thu, 20 Jan 2000 17:29:59 +0530

Hello Brian,

1. This is regarding mandatory parameters and was raised recently on the
mailing list, but to which there was no reply. So I am resending the
same.
In section 7.1.1
"Unspecified mandatory parameters (i.e. mandatory parameters not
specified in a descriptor)
result in the command responder retaining the previous value for that
parameter"
Does that mean that none of the parameters in a descriptor are actually
"mandatory" in the real sense of the term ?

2. Consider the situation of failure of an MGC and MGC handing off MG to
a different MGC.
Section 11.5 says that
"When the MGC initiates a HandOff, the handover should be transparent to
the operations on the Media Gateway.  Transactions can be executed in
any order, and could be in progress when the ServiceChange is executed.
Accordingly, commands in progress continue, transaction replies are sent
to the new MGC, and the MG should expect outstanding transaction replies
from the new MGC.  Since all connections should stay up."

However there is some text in the ALF Section Annexe D, in D.1.4, which
also talks about handoff and which says,
"In order to account for the possibility of an undetected or in-progress
"failover", we modify the classic algorithm so that if the Media Gateway
receives a valid ServiceChange message announcing a failover, it will
start transmitting outstanding commands to that new MGC.  Responses to
commands are still transmitted to the source address of the command."

Can you please clarify what action actually needs to be taken, the one
specified in section 11.5, where the transaction replies are sent to the
new MGC
    Or
the one specified in D.1.4., where the command responses are sent to the
source address of the command ?

Regards,

Shalini Philip
Ficon Technology
E-Mail : mailto:[email-masked]
Web    : http://www.ficon-tech.com

---

From: "Rosen, Brian" <[email-masked]>
Date: Fri, 21 Jan 2000 11:57:26 -0500

I'm sorry if I missed sending a reply to this

-----Original Message-----
From: Shalini Philip [mailto:[email-masked]]
Sent: Thursday, January 20, 2000 7:00 AM
To: [email-masked]
Subject: Questions on MEGACO

Hello Brian,

1. This is regarding mandatory parameters and was raised recently on the
mailing list, but to which there was no reply. So I am resending the same.
In section 7.1.1
"Unspecified mandatory parameters (i.e. mandatory parameters not specified
in a descriptor)
result in the command responder retaining the previous value for that
parameter"
Does that mean that none of the parameters in a descriptor are actually
"mandatory" in the real sense of the term ?

Yeah, maybe it's a poor choice of words.  The idea is that some things
really are optional. The ones that aren't really optional have to have a
value at all times.  They have a default, you can change it in null.  When
you Add it to a context, you usually specify the value if the default is not
what you want.  Leaving it out of the descriptor causes it to keep
the current value.

2. Consider the situation of failure of an MGC and MGC handing off MG to a
different MGC.
Section 11.5 says that
"When the MGC initiates a HandOff, the handover should be transparent to the
operations on the Media Gateway.  Transactions can be executed in any order,
and could be in progress when the ServiceChange is executed.  Accordingly,
commands in progress continue, transaction replies are sent to the new MGC,
and the MG should expect outstanding transaction replies from the new MGC.
Since all connections should stay up."

However there is some text in the ALF Section Annexe D, in D.1.4, which also
talks about handoff and which says,
"In order to account for the possibility of an undetected or in-progress
"failover", we modify the classic algorithm so that if the Media Gateway
receives a valid ServiceChange message announcing a failover, it will start
transmitting outstanding commands to that new MGC.  Responses to commands
are still transmitted to the source address of the command."

Can you please clarify what action actually needs to be taken, the one
specified in section 11.5, where the transaction replies are sent to the new
MGC
    Or
the one specified in D.1.4., where the command responses are sent to the
source address of the command ?

Yes, we must fix this.  I think you have to send the replies to the old one.
Any other opinions?