8.1 Privacy Considerations

   The address reachability information distributed by ESADI has
   substantial privacy considerations under many, but not all,
   circumstances.

   For example, if ESADI were used in a TRILL campus with independent
   user end stations at the edge, the MAC addresses of such end
   stations could uniquely identify the users of those end stations.
   Their reachability would be sensitive information and, particularly
   if logged, be revealing of their users.  On the other hand, if
   TRILL is being used to implement an Internet Exchange Point (IXP)
   to connect Internet Service Providers (ISPs), the MAC addresses
   being advertised in ESADI would typically be those of the ISP's
   directly connected IP router ports, since Layer 3 routers bound the
   TRILL campus, for which there would be few privacy concerns.

   However, records of MAC attachment, including a modest amount of
   history, perhaps a few days worth, can be useful in managing a
   network and trouble shooting network problems. It might, in some
   casees, also be legally required or required for billing or the
   like.

   Network operators should seek a reasonable balance between these
   competing considerations for the circumstances of their particular
   networks where ESADI is in use. They should not maintain logs of
   MAC reachability information for any longer than is clearly
   required.