Arvola, One of your comments was on the restriction about not having Acks on Errors. We can have Acks on Errors if we stipulate no Errors on Acks. If we want Errors on Acks then we must stipulate no Acks on Errors. If we have both, then we have the potential for endless loops. I question the need for Errors to be sent reliably. I see some significant benefit for having Errors returned on bad Acks. Regards, David Fischer Drummond Group.