The index value which uniquely identifies the interface to
which this entry is applicable. The interface identified by
a particular value of this index is the same interface as
identified by the same value of RFC 1573's ifIndex.
The subnet mask associated with the IP address of this
entry. The value of the mask is an IP address with all the
network bits set to 1 and all the hosts bits set to 0.
The value of the least-significant bit in the IP broadcast
address used for sending datagrams on the (logical)
interface associated with the IP address of this entry. For
example, when the Internet standard all-ones broadcast
address is used, the value will be 1. This value applies to
both the subnet and network broadcasts addresses used by the
entity on this (logical) interface.