Yup. And either way, you can solve the problem with capital. (Having a bunch of money laying around to cover the shortfall in the case of A/R, or having a very large burstable uplink with a small commit in the case of overselling bandwidth.)
Of course, burstable uplinks all suffer from the 'best effort' issue... if you go beyond your CIR, well, there's usually headroom, but not always.
Of course, burstable uplinks all suffer from the 'best effort' issue... if you go beyond your CIR, well, there's usually headroom, but not always.