Internet Authentication Service for Windows 2000 - The official white paper from Microsoft on IAS, (Microsofts implementation of the RADIUS standard (Remote Authentication Dial-in User Service). 137 pages.
Technical Overview of Windows Server 2003 Networking and Access Technologies - This white paper provides a technical overview of networking and communications enhancements in Windows Server 2003. Concepts in this paper are eg. L2TP/IPSec, mobility, VPN, NAT, NLB, TCP/IP, IPv6, DHCP, DNS, WINS and IAS. 59 pages.
Windows XP Wireless Deployment Technology and Component Overview - This official Microsoft paper addresses Wireless technologies. It sums up the processes of connecting, authenticating and encrypting, and goes into different technologies such as RADIUS/IAS, EAP and certificates. 41 pages.