Limitation of nonStandardData

Scott Petrack Scott_Petrack at VOCALTEC.COM
Tue Dec 2 05:06:46 EST 1997

This problem has bothered me for a long time. I considered many times
introducing into the VoIP Forum an OID which would be used precisely as Jim
suggests, so that the entire industry could signal a SEQUENCE of

One example of why this is necessary is so that when someone else uses our
stack we can both pass non-standard parameters.

Question to all "industry techie-leaders" (by definition people reading
this message ;-)). Is there any chance of gettting agreement on this or is
it too late? Of course we can do it privately (and we do), but it would be
very useful to have everyone do it together, no?

I would offer an OID in the VoIP forum's space, but I really could not care
less about ownership. If there is a way to put this into the standard, that
would be fantastic.


jtoga at on 12/01/97 09:42:53 PM

Please respond to ITU-SG16 at

To:   ITU-SG16 at
cc:    (bcc: Scott Petrack)
Subject:  Re: Limitation of nonStandardData

An easy fix for backward compatability is to simply define a particular
'nonStandardParameter' as a "SEQUENCE OF nonStandardParameter".


At 07:02 PM 12/1/97 -0000, you wrote:
>Dear All,
>I have noticed that there is a limitation in H.225 (and H.245) on how
>nonStandardData is included in messages.  Basically only one
>non-standard element can be included in each PDU.  This is because of
>the syntax:
>        nonStandardData NonStandardParameter,
>What is really required for a truly extensible protocol is:
>        nonStandardData SEQUENCE OF NonStandardParameter,
>This is especially important if a gatekeeper wants to insert
>nonStandardData into a message that already has nonStandardData added in
>to it by an endpoint.
>This may be too late to fix for H.225, but we can fix this for the
>H.450.x protocols.
>Pete Cordell
>BT Labs
>E-Mail: pete.cordell at
>Tel: +44 1473 646436
>Fax: +44 1473 645499
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