As Facebook might caution us, "it's complicated". It's not uncommon for a 2.5G wave to be protocol-agnostic most of the way through, and then required to pass through a SONET/SDH framer at the end... You've be well-served to find somebody at your carrier clued on their transport platform, or absent that, able to read off the configuration options their shiny OSS GUI provides. If you could shed some light on who the carrier is, chances are they've got a customer or two on the list able to provide some implementation specifics. The silver lining in this all is nobody's buying 2.5G wave service, and as such, there's a plethora of cheap hardware options on the secondary market able to handle the requisite circuit emulation and/or packet forwarding -- Cisco 15454/GSR/OSM, Turin, Juniper routers with I-1OC48-SON-SMIR and P-1GE-SX-Bs -- choose your poison. (Easier still, albeit far less fun, upgrade to a 10G {LAN,WAN}-PHY interface for a couple pennies more. :-) HTH, -a