why pay the complexity and cost overhead of SONET if you're not building rings?
In a IP backbone, we prefer to have 2 diverse path's to IP use, than one with protection, this gives a better overall utilisation, and more control of what happends.
i don't entirely agree. two reasons. one: you have to build headroom into your network (whether sonet or IP) to handle at least 2X nominal load -- and this is harder, not easier, in the case of IP level diversity (since it is easier to squeeze past the 2X requirement when the beancounters aren't giving you everything you say you need, and they'll learn this.) two: i prefer to have redundancy at the physical level AND at the IP level -- because back when all my network was carrying was spam and netnews, i actually welcomed the peace and quiet of an outage, but now that there are customers involved, i want peace of mind instead. i take it that it's mostly the bypass carriers and the long haul carriers who cheese out on ringing their sonet on diverse paths? i know pac bell rings just about everything. how are the other regionals?