Yeah, seems to be A Deepness in the Sky:

https://en.wikipedia.org/wiki/A_Deepness_in_the_Sky#Interste...

Recently read A Fire Upon the Deep personally, and don't recall much/any mention of it there. :)

Both are great reads. Fire Upon the Deep had some cooler concepts, but narrative-wise I prefer Deepness in the sky. The emotional response I had to the memory-control-slavery aspects made my blood boil.