If the ISD is supposed to involve interstellar (as opposed to merely interplanetary) networks, you might want to bear in mind the bandwidth of a starwisp full of memory diamond.
Thanks! (And thanks for commenting on this.) As of right now in the story, we're mostly talking about "merely interplanetary" networks, and I'm mostly staying away from anything below OSI level 3.
While I can kid myself that "sys admin punk/space opera" is something that people greater than you and I might be interested, I'm having a hard time being able to make the link-layer sexy.
When it gets interstellar in scope, I'm game/interested in playing with the idea a bit further. There are two things that I think could happen:
There'll just be some sort of ansible, because it's fiction we are writers and that's our choice to make. I tend to just assume ansible because it makes the parts of stories that most people like (character, plot movement) work more easily.
There'll be delay's and sync lag. And fancy merge algorithms that take a lot of processing power to manage. And that might make for interesting stories.
I'm leaning in this direction anyway.