The REAL Mutt Lange would know the answer! ...Then again the real Mutt Lange was stupid enough to actually cheat on Shania Twain, so his opinion means little here
. Just messing wit ya........
Assuming you're talking about an analog console hooked up to a computer running multitrack software (I have to ask because there's so many abuses of the term "DAW" around here that it could mean almost anything), the routing will require enough channels of I/O (A/D and D/A converters) between the two as you desire.
If you wish, just for example, to be able to record 8 simultaneous channels from 8 sources, you will need a minimum of 8 channels of analog-to-digital (A/D) conversion going in to your computer. Additionally you will need an analog mixer with either 8 output busses or 8 input channels that have direct out jacks as well.
You then need to go back out to you miser for your OTB mixing, so you also need as many channels of (D/A) conversion as you have tracks that you want to be able to simultaneously mix.
Additionally, you also need to consider other miscelaneous I/O. If you wish to send a stereo mix to your CR monitors from your computer and not just what's in the analog mixer, then you'll need those two extra channels of D/A out from the computer. If you wish to record submixes out of your mixer as well as direct channels, you'll want to have enough A/D input into your computer to handle the maximum number of combined direct and bus outs from the mixer that you want to be able to simultaneously handle.
I'd also recommend the use of a patch bay between the mixer and your I/O interface so you have the flexibility of routing what you want to use at the time without necessarily having to have enough I/O for everything at once. For example, your mixer may have (just as an example) 12 direct outs, 8 submix buses, and a stereo master bus. this would indicate on the surface that you'd need 22 channels of D/A interface into your computer, and that would be great to have. But you won't always need to be running all possible outputs at one time, so if you can't afford that much, you could have, say, 8, 12 or 16 channels of actual interface into the computer, and use the patch bay to select which mixer outs you need to use at any given time.
HTH,
G.