Hi, I whould like to know please, who sends ack? The root of the tree or the parent of the node I mean the forwarding node? Thank you very much. All the bests, Nahr Elk -------------- next part -------------- An HTML attachment was scrubbed... URL: https://www.millennium.berkeley.edu/pipermail/tinyos-help/attachments/20080506/cbadfb5e/attachment.htm