Local Area Networks (LANs) in Aircraft - FTP Directory Listing - FAA

encrypted and then encapsulated with a packet header of a conveying network. That packet is
then being tunneled across that conveying network to a point where the encapsulating/encryption
process is reversed and the packet is re-introduced into a network operating at the original
classification level. Many people refer to the conveying network as being BLACK, i.e., that they
are often unclassified networks, and the conveyed network as being RED, which means that they
may be classified at any specific classification level. Regardless, RED network packets are the
original plain text packets, and BLACK packets are the cipher text (i.e., encapsulated and
encrypted) packets. (Note: because the RED (customer) packets are encapsulated into that
conveying BLACK network, the BLACK network itself is referred to as cipher text, even though
the native non-VPN communications within that network are also normal plain text packets.)
RED packets have only one IP layer header and operate in the normal manner, but BLACK
packets have two IP layer headers: the original IP layer header that was used by the original end
user and the encapsulated IP layer header that is used by the conveying network.
Figure 18 represents a possible mechanism for operating military aircraft within the DoD’s GIG
infrastructure. The figure has two distinct elements: (a) represents possible physical network
systems and (b) shows how these systems logically work together.
Aircraft A
Ground Station
Aircraft
Viewpoint
Aircraft B
Red IP
(SBU)
Red IP
(Secret)
Black IP
Black Router
IP
Wireless
media
Black IP
Black Router
IP
Router
Red IP
(SBU)
Red IP
(Secret)
Red IP
(SBU)
Red IP
(Secret)
Black IP
Router
(a)
= COMSEC device
Logical
View
of “Big
Picture”
NIPRNET
SIPRNET
Other Black GIG networks
Top
Secret
(b)
Logically Networked Aircraft
Black IP
IP
Router
Black
Network
Black Black IP
IP
Router
Red IP
(SBU)
Red IP
(Secret)
Red IP
Top Secret
SBU
Network
Secret
Network
Top
Secret
Network
Figure 18. Representation of how Aircraft may Function Within the GIG
Figure 18(a) shows that the aircraft may internally support computing devices that operate at a
specific classification level. These computing devices may be connected via onboard networks
(LANs) that operate at a specific classification level. In those cases where aircraft internally
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