[Robustness] End to End Acknowledgement Contribution

Hi,

Please find attached our write-up on end to end acknowledgement. As discussed in our last Robustness Group Conference Call, adding these acknowledgements at H.323 level to messages which invoke no responses will prevent call state mismatch should these messages be lost.

We hope the group will give some response during Tuesday's conference call. The list of messages that need to be acknowledged shown in the document is preliminary and we would welcome comments and suggestions.

Regards, Tim Chen

------------------------------------------------------------ Tim Chen Trillium Digital Systems, Inc. Phone: +1 310 442 9222 Fax: +1 310 442 1162 email: tim@trillium.com http://www.trillium.com