3.2.1.1 Table of Subnets
The client maintains a table of all IP subnets for which it currently holds the following:
A local IP address.
A table of server addresses.
Each row of the table represents a single subnet and includes the following data:
A flag M_ATTACHED that is true if the client is currently attached to this subnet.
A pointer to a table of server addresses.
For each IPv4 subnet, the client saves its subnet ID, subnet mask, and DNS domain suffix (or an empty string if not available).
For each IPv6 subnet, the client saves its subnet ID and subnet mask.