In an earlier post on SLO I promised to get back with more information about the usage of single logout, as Feide adds more and more services to the SLO service.  The graph below shows the ratio of Single Log Out (SLO) to Single Sign On (SSO) for the Feide production Moria4 site.  It is interesting to note that the SLO to SSO ratio is increasing (the initial fluttering is due to pre-production testing), and there is a marked jump at the same time as several reliable service providers were added.  A peak at the underlying data indicates that several services have logout ratios above 50%, among these are library databases and exam registration.  SLO to SSO ratio

Even if all services implement SLO, not all services have a good location for the SLO button.  In practice this leads to not all users having access to logout.  Most users still close the browser to log out from a service, or does not log out.  For those who do not log out, the session timeout functions as their logout.  Session timeout in Feide takes several hours, which is a long time compared to BankID where the session lifetime is minutes.

The Moria4 site above went into production April 29, and several major service providers were added in late May.  The overall SSO traffic is shown below.

Single Sign On for Moria4

More information about the technical implementation is available in Andreas’ presentation on SLO from TNC2009

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