C Local Area Network
From GovITwiki
This network, commonly referred to as the CLAN, is used within DHS to communicate top secret information with the Intelligence Community. It provides connectivity to the Department of Defense’s Joint Worldwide Intelligence Communications System to access, receive, and share intelligence information.
Description from General Accounting Office document GAO-07-455
The GovITwiki Intelligence Agencies page lists the U.S. government's major secret and sensative but Unclassified networks.
