[VOIPSEC] Telcos and VOIP/SIP security

[Hank Nussbacher]

I am looking for documents from traditional CLECs that detail the security 
considerations when migrating from an old style (exchange) based network to 
a new style VOIP/SIP/NGN style network.  I have read the docs at:
http://hhi.corecom.com/voipsecurity.htm
http://www.vopsecurity.org
http://www.voipsa.org/
and the NIST doc is interesting but I am looking for something written by a 
Sprint/MCI/AT&T type of CLEC.  Anything out there?

Thanks,
Hank