eAuthentication is an authentication service provided by one remote server to other distributed servers, on the Internet or an intranet.
Similar to credit card verification services that are provided by third parties to eCommerce web sites, eAuthentication services provide identity verification services primarily to web sites but also to intranet servers.
There are a number of eAuthentication implementations in the market today. Some use RADIUS based eAuthentication and other are using a more elaborate proprietary API.
References
EAuthentication Wikipedia(Text) CC BY-SA