ipv6AddrPrefixAdvPreferredLifetime 1.3.6.1.2.1.55.1.7.1.5

It is the length of time in seconds that this prefix will remain preferred, i.e. time until deprecation. A value of 4,294,967,295 represents infinity. The address generated from a deprecated prefix should no longer be used as a source address in new communications, but packets received on such an interface are processed as expected. This object is obsoleted by IP-MIB::ipAddressPrefixAdvPreferredLifetime.