[parley]

You remember correctly. This is present in "A fire upon the deep" by Vinge, which is one of the best sci-fi books I have read (although I am not particularly well read). Really, that book contained several concepts (the drifting tech zones, the hive mind mechanisms, etc) that made it an amazing read. I would recommend it to anyone who appreciates sci-fi.

EDIT: I forgot to add that the book was also a Hugo Award (Best Novel) winner, which I just noticed/remembered as I took it down from my bookshelf to re-read it... =o)