2 AlphaWhiskey:
In real life datalink on russian planes can be receved from AWACS, Comand center, the other airplanes of sqadron.
From open sources we know, thet there are two lewels of datalink exchange:
Betwen comander of sqadron and comander of formation
And betwen comander of formation and pilots of formation.

Each pilot have a possibility to translate 10 targets to 4 preprogrammed planes of his squadron. (It can be understanded, if we'll look to the panel under the right arm of a pilot of Su-27 - 4 numered buttons for planes and 10 numered buttons for targets).

Datalink give possibility to a pilot to know a air situation.
Datalink give to a pilot all information about target, it is controling the radar and IRST scan zones (this we can know from open sources), controlling turning on and locking on moments of radar and IRST. It give to a pilot instrumental flight control directive comands to make an full atack manuver (from a take off, to a missile launch and CAC).