Subject: [Megaco] Protocol Version Negotiation for ASN.1 encoding

From: "Maruo, Luciano Mikio" <[email-masked]>
Date: Tue, 20 Dec 2005 15:50:26 -0200

Hi,

I have a question regarding the protocol version negotiation when using
ASN.1 encoding for H.248.

According to chapter 11.3, version 1 should be used.

" 11.3 Negotiation of protocol version

A ServiceChange command from a MG that registers with an MGC shall
contain the version

number of the protocol supported by the MG in the ServiceChangeVersion
parameter. Regardless of

the version placed in the ServiceChangeVersion parameter, the message
containing the command

shall be encoded as a version 1 message. "

 

However, according to ANNEX A.2, in the ASN.1 specification, it says
that the version to be used is equal to 2.

Message ::= SEQUENCE

{

version INTEGER(0..99),

-- The version of the protocol defined here is equal to 2.

mId MId, -- Name/address of message originator

messageBody CHOICE

{

messageError ErrorDescriptor,

transactions SEQUENCE OF Transaction

},

...

}

The question is: which version (not ServiceChangeVersion) should be used
for protocol negotiation in binary encoding of the H.248? 

Can I use version 2?

Thank you very much,

Luciano Mikio Maruo

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---

From: "Kevin Boyle" <[email-masked]>
Date: Tue, 20 Dec 2005 12:57:11 -0500

It does not says the version to be used is 2. It says the version
defined there is 2.
 
Per the spec, all protocol negotiation messages have to be encoded as
Version 1, otherwise version negotiation will not work.  For example, a
couple of things were added to ServiceChange in Version 3.  If an
initial registration message was sent as V3 to an MGC that did not
support V3, you would end up getting a syntax error back, rather than
negotiating to the lower version.
 
Kevin

________________________________

	From: [email-masked] [mailto:[email-masked]]
On Behalf Of Maruo, Luciano Mikio
	Sent: Tuesday, December 20, 2005 12:50 PM
	To: [email-masked]
	Subject: [Megaco] Protocol Version Negotiation for ASN.1
encoding

	Hi,

	I have a question regarding the protocol version negotiation
when using ASN.1 encoding for H.248.

	A ServiceChange command from a MG that registers with an MGC
shall contain the version

	number of the protocol supported by the MG in the
ServiceChangeVersion parameter. Regardless of

	the version placed in the ServiceChangeVersion parameter, the
message containing the command

	 

	However, according to ANNEX A.2, in the ASN.1 specification, it
says that the version to be used is equal to 2.

	Message ::= SEQUENCE

	{

	version INTEGER(0..99),

	messageBody CHOICE

	{

	},

	...

	}

	The question is: which version (not ServiceChangeVersion) should
be used for protocol negotiation in binary encoding of the H.248? 

	Can I use version 2?

	Thank you very much,

	Luciano Mikio Maruo