Asynchronous Transfer Mode ATM Ethernet Token Ring and X25 are examples of

Asynchronous transfer mode atm ethernet token ring

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Asynchronous Transfer Mode (ATM), Ethernet, Token Ring, and X.25 are examples of common network topologies that are used to control the transmission of data. Each uses some form of data unit packaging that is referred to as a frame or cell, and represents a manageable portion of the communication. Coax, fiber, twisted-pair wire, and microwave are a few examples of computer communications media that can provide the foundation for the specific topology to transmit data units. The location of a sniffer is a defining factor in the amount and type of information collected. The importance of location is relative to the topology and media being used. The topology defines the logical organization of systems on a network and how data is negotiated between them. The medium being utilized can assist in determining the environment simply based on its location. A basic example of this logical deduction is a simple Ethernet network spread across multiple floors in a building with a connection to the Internet. Ethernet is the topology at each floor and typically uses CAT5 cabling. Fiber cables can be used to connect each floor, possibly using FDDI as the topology. Finally, connection to the Internet typically consists of a serial connection using a V.35 cable. Using this deduction, it is safe to say that a sniffer with serial capabilities (logically and physically) placed at the Internet router can collect every packet to and from the Internet. It is also feasible to collect all the data between the floors if access to the FDDI network is obtained. 1792 Information Security Management Handbook
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It is necessary to understand the relationship of the topology to the location and the environment, which can be affected by the medium. The medium being used is relevant in various circumstances, but this is inherently related to the location. Exhibit 135.1 explains in graphical format the relationship between the location of the sniffer, the topology, and the medium being used. There are three buckets on the left of a scale at varying distances from the axis point, or moment. Bucket A, the furthest from the axis point, represents the weight that the sniffer’s location carries in the success of the attack and the complexity of implementing a sniffer into the environment. Bucket A, therefore, provides greater leverage in the calculation of success relative to the difficulty of integration. Nearly equally important is the topology , represented by bucket B. Closer to the axis point, where the leverage is the least, is the medium represented by bucket C. Bucket C clearly has less impact on the calculation than the other two buckets. Adding weight to a bucket is analogous to changing the value of the characteristic it represents. As the difficulty of the location, topology, or medium increases, more weight is added to the bucket. For example, medium bucket C may be empty if CAT5 is the available medium. The commonality of CAT5 and the ease of interacting with it without detection represents a level of simplicity. However, if a serial
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