This chapter attempted to present the basic problems as well procedures regarding to authentication, authorization, and accounting. Since the topic of authentication is a rather complicated one that has gone under tremendous amount of progress, we will devote another chapter on that topic. As mentioned earlier, authorization is less standardized. However, we expect that with the increase in user mobility and service offering, the field of authorization will go through much further progress. For now, most of the work related to authorization is categorized under policy frameworks. The reader is referred to the Policy Framework working group in IETF for further information in the policy area: http://ietf.org/html.charters/policy-charter.html.
Also more information about authorization can be found in the AAA applications examples [AUTHAPP2905].
IETF documentations such as [ACCMGM2975] and [POLACC3334] can provide more information on accounting.
In the area of billing and accounting, many service operators may deploy their own specific technologies that follow their own policies. More information can be found from the companies providing AAA servers to these service operators. Examples are
Bridgewater systems: http://www.bridgewatersystems.com/document_library/
Interlink networks: http://www.interlinknetworks.com/resource/wp5-1.htm
Funk software: http://www.funk.com/