DODAG Information Object(DIO) carries information that allows a node to discover a RPL Instance, learn its configuration parameters, select a DODAG parent set and maintain the DODAG.
DODAG Information Object(DIO) Lifetime value calculated from default Lifetime value and DIO Destination Lifetime Unit for DODAG set.
Open a source code file in a following Location:
>>contiki-ng/os/net/routing/rpl-lite/rpl-icmp6.c.
Here, rpl_icmp6_dio_output function handling DIO Lifetime Calculation.