IP Spoofing has its good uses

I am over here doing an article on IP Spoofing for my TCP/IP class and came across some very interesting information. Although IP Spoofing is only used for bad things, spoofing has its good uses. I never thought Spoofing could be used for something good. This excerpt on dictionary.com reads:

One of the good uses for Spoofing is to reduce the required bandwidth on network by having devices such as bridges or routers answer for remote devices. This is done to fool (spoof) a LAN device into thinking a remote host is still connected to the network when in actually this host could be disconnected from the network. This saves bandwidth because no packet is ever sent out on the WAN. ["Network Spoofing" by Jeffrey Fritz, BYTE, December 1994, pages 221 - 224].

This is good to know because IP Spoofing always has associated with it negative connotations.