I had also noted this potential limitation. While the 'SEQUENCE OF' is ther nicest fix for it, an alternative possibility is to wrap (encapsulate) the original nonStandardData in the new one (as part of the data) and unwrap it later. This would work where the message path is EP-GK-GK-EP and the EP's are exchanging nonStandardData plus the GK's are also. Douglas At 19:02 1/12/97 -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 ================================= Pete Cordell BT Labs E-Mail: pete.cordell@bt-sys.bt.co.uk Tel: +44 1473 646436 Fax: +44 1473 645499 =================================