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For example, user A and user B both try to access a quiet link at the same time. Since they detect a collision, user A waits for a random time between 0 and 1 time units and so does user B. Let's say user A chooses a lower back-off time. User A then begins to use the link and B allows it to finish sending its frame. If user A still has more to ...
Example of a system context diagram. [1] A system context diagram in engineering is a diagram that defines the boundary between the system, or part of a system, and its environment, showing the entities that interact with it. [2] This diagram is a high level view of a system. It is similar to a block diagram.
The channel access control mechanism relies on a physical layer multiplex scheme. The most widespread multiple access method is the contention-based CSMA/CD used in Ethernet networks. This mechanism is only utilized within a network collision domain, for example, an Ethernet bus network or a hub-based star topology network.
Historically, access control models have included mandatory access control (MAC), discretionary access control (DAC), and more recently role-based access control (RBAC). These access control models are user-centric and do not take into account additional parameters such as resource information, the relationship between the user (the requesting ...
In this matrix example there exist two processes, two assets, a file, and a device. The first process is the owner of asset 1, has the ability to execute asset 2, read the file, and write some information to the device, while the second process is the owner of asset 2 and can read asset 1.
Common physical security access control with a finger print A sailor checks an identification card (ID) before allowing a vehicle to enter a military installation.. In physical security and information security, access control (AC) is the selective restriction of access to a place or other resource, while access management describes the process.
Frequency-division multiple access (FDMA) is a channel access method used in some multiple-access protocols. FDMA allows multiple users to send data through a single communication channel, such as a coaxial cable or microwave beam, by dividing the bandwidth of the channel into separate non-overlapping frequency sub-channels and allocating each sub-channel to a separate user.
The line between logical access and physical access can be blurred when physical access is controlled by software. For example, entry to a room may be controlled by a chip and PIN card and an electronic lock controlled by software.