interop with non-ip nets?

["Robinson, Richard" <RRobin01@sprintspectrum.com>]

I'm having trouble understanding this requirement that is in the current
draft (pasted below).

"Interoperability with non-IP Networks  

   The wireless Internet framework needs to provide the capability to 
   receive sessions from, and terminate sessions to, circuit switched 
   networks that include public switched and existing cellular mobile 
   networks. The wireless Internet framework needs to provide support 
   for roaming users and roaming terminals (with appropriate multi-mode 
   and multi-band functions). This needs to include roaming between IP 
   based and non-IP based networks. In detail the wireless Internet 
   framework needs to support inter-working with GSM MAP and ANSI-41 
   MAP signalling. "

From a Sprint perspective, we envision our "pre-all-ip or 3g-legacy" network
as packet switched domain only.  I can see the need for packet switched mode
interoperability between IP and other packet type nets but how does circuit
mode fit in?  Maybe i'm mis-reading this draft requirement.  Can anyone
help?

Richard Robinson
Sprint PCS
15405 College Boulevard
Lenexa, Kansas 66219
913.890.4242 (fax 4100)
MS - KSLNXZ0201
rrobin01@sprintspectrum.com