A network not controlled by the organization.
Source(s):
CNSSI 4009-2015
from
NIST SP 800-53 Rev. 4
NIST SP 800-171 Rev. 2
NIST SP 800-172
NIST SP 800-37 Rev. 2
NIST SP 800-53 Rev. 5
NIST SP 800-171 Rev. 1
[Superseded]
NIST SP 800-53 Rev. 4
[Superseded]
under External Network