This is Greg Bear'sEgan's Diaspora.
From Wikipedia:
By 2975 CE (Universal Time), the year in which the novel begins, humanity has "speciated" into three distinct groupings:
fleshers, biological societies consisting of statics, the original, naturally-evolving race of Homo sapiens...
gleisner robots, individual software-based intelligences housed inside artificial anthropoid, or flesher-shaped, physical bodies ...
the citizens, intelligence as disembodied computer software running entirely within simulated reality-based communities known as polises.
