This paper provides an overview of identity management with emphasis on the federated approaches, covering related standard specifications, and security and privacy considerations. Actual business cases, ranging from B2E to B2C in different industries, such as mobile communications, gaming, and digital TV are introduced. The Liberty Alliance identity frameworks are used as a concrete example to illustrate federated identity management technologies. Moreover, other approaches, such as SAML, shibboleth and WS-Federation, are compared.

Certain relationships between successive packet loss patterns and packet spacing are described. To observe a successive packet loss pattern, one possible method is to investigate test packets that are generated at certain intervals (e. g. , Poisson interval, constant regular interval). However, successive packet loss strongly depends on the interval generated. If test packets are generated with long intervals, then successive loss pattern cannot be shown. Thus, in such a method, where the packet intervals may sometimes be long or short, the successiveness of the packet loss should be considered in terms of the packet spacing. To clarify the relationship between the successive packet loss and the packet spacing, we analyze data based on observation of an actual network with the loss window size as a parameter. We find that when the packet spacing is narrower, i. e. , has a shorter interval, the probability becomes higher that the packet immediately following a single packet loss would also be lost.