I found this section of a Telephony Online article interesting: Though networking trends point toward an evolution to mesh networks, nationwide carrier networks currently lack the physical diversity that would help carriers realize the benefits of true mesh networking, Poll said. Qwest, for example, has about three or four cross-country arteries that correspond to railway rights of way. Replacing that with a more mesh-like architecture would increase the complexity of operating the network. For one thing, it would require more uniformity in the capacities of various network routes. "You'd have to have units of 10 Gb/s traffic between all points on the network before this becomes economically viable," Poll said. "When you place IP capacity, you have to place a lot of standby capacity to carry traffic along different paths. If we could get greater physical diversity in place, we could greatly diminish the amount of standby capacity we have to take." In order to realize the benefits of mesh networking, Poll said, carriers will need to cooperate with each other more than they currently do, using fiber swaps to increase the geographic diversity of network paths. http://telephonyonline.com/access/news/ofc-qwest-optical-0226/ To keep this OT as much as possible, my question is if a mesh-configuration of backup routes (where one link could provide 'protection' for many) would be considered a sufficient replacement for SONET rings, or if the Qwest CTO is really trying to get out of providing sub 50-msec protected loops and encouraging L3 and above protection schemes, so that they can even further over-subscribe their network. Frank