5.2.c Implement and troubleshoot IPv6 first hop security

5.2.c [iv] Device tracking

The IPv6 Device Tracking feature provides IPv6 host liveness tracking so that a neighbor table can be immediately updated when an IPv6 host disappears. The feature tracks the liveness of the neighbors connected through the Layer 2 device on a regular basis in order to revoke network access privileges as they become inactive.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 5378-5380).  . Kindle Edition.

http://www.cisco.com/en/US/docs/ios-xml/ios/ipv6_fhsec/configuration/15-sy/ip6-dev-track.html