i have been suggesting a DACS for many years. then all one needs is one channelized oc48 and it's fat city.
As passive DWDM becomes dirt cheap, having a loop carrying to a redundant optical (wavelength) cross-connect has advantages, like you can bilaterally upgrade your peering line cards without having to bother to inform / be bothered by the exchange point (remember MAE-ATM). I can't see why people would want to put in less than an OC-3. n x OC-3 + passive DWDM is (I believe) cheaper than OC-48 channelized (per bit per second) for many values of n (i.e. spreading the DWDM cost across many OC-x's.) - & this will last until n x parallel OC-192 is insufficient for bilateral cross connect. By the time anyone listens to your (good) DACS idea, 2.4Gbps (total) won't be enough. -- Alex Bligh VP Core Network, Concentric Network Corporation (formerly GX Networks, Xara Networks)