I once found an interesting open source wireless protocol for transmitting short messages over failure-prone gprs-links. They tested the protocol by driving around with a laptop, while transmitting its gps-position via the protocol. As they drove out of gprs-coverage, the messages queued for later transmission.

Can anyone remember the name or URL of this protocol? (I just accidentially deleted my Bookmarks... - DUH!)

kind regards Jon Loldrup