The value of object tmnxDhcpSvrLeaseIAOptionType indicates
the type of the option.
- 'notApplicable (0)': AI is not applicable to this lease.
- 'iaNa (1)':
The IA_NA option type is used to request the assignment of
non-temporary addresses.
- 'iaPd (2)':
The IA_PD option is used to carry a prefix delegation identity
association, the parameters associated with the IA_PD and the
prefixes associated with it.