Hi there GEAR GRINDER,
Octalink is the somewhat new Shimano BB/crank system. See, the BB is splined, not square tapered like the outdated Campy BBs (hehehe ;D). It has 8 splines, hence the name OCTALINK. Gee, Shimano really has a lot of innovations eh?
BTW, nice choice of components. If you have any trouble with the D/A BB, just get an Ultgrea BB.
Cheers!