An alternate form of multihoming does not require a second network adapter; instead, you assign multiple IP addresses to the same adapter on one computer. Microsoft Windows XP and other operating systems support this configuration as an advanced IP addressing option. This approach gives you more flexibility to control incoming network connections from other computers.
Combinations of the above - configurations with both multiple network interfaces and multiple IP addresses assigned to some or all of these interfaces - are also possible.
The concept of multihoming is increasing in popularity as new technologies are adding more support for this feature. IPv6, for example, offers more network protocol support for multihoming than traditional IPv4. As it becomes more common to use computer networks in mobile environments, multihoming allows helps solve the problem of migrating between different types of networks while traveling.
See also > Can A Home Network Share Two Internet Connections?
How to setup dual NIC, multi-homed host to dual ethernet network