ccna practice quiz

ccna practice quiz.topology. An example of a point-to-point topology is where two routers are connected via a WAN dedicated circuit.In a star topology, there is a central device that has many point-to-point connections to other components. A star topology is used in situations where many components need to be connected, and one media type that uses a star topology is lOBaseT Ethernet. When using a star topology to connect components, the computers are connected to a central hub or switch. The main problem with a star topology is that if the central device fails, all other devices cannot communicate with each other. To solve this problem, an extended star topology can be used. An extended star topology is actually a star topology with multiple interconnections.In a bus topology, all components are connected to a single cable and share that cable. Some media types (such as 10Base5 and 10Base2 Ethernet) use a bus topology. To provide a bus topology, special connectors or transceivers are often used to connect the cables. For example, in 10Base5, each device is connected to the same coaxial cable through a plug-in tap (vampire tap); this device provides a physical connection from the network device to the cable by plugging into the coaxial cable.In a ring topology, each device is connected to the next device, and the last device is connected to the first device. When implementing a ring topology, either a single ring or a dual ring can be used. Dual rings are typically used when redundancy needs to be provided; this way if one component fails, it can still operate normally as a single ring, as shown in Figure 1.2. Fiber Distributed Data Interface (FDDI) is a media technology that uses dual rings to connect computingmedium technology that uses dual rings to connect computer components. Single-ring topologies do not have this redundancy.Practical experience physical bus topologies share a single cable. Today's networks rarely use token rings and FDDL1.2.1 Physical and Logical TopologiesA distinction must be made between physical and logical topologies. Physical topology refers to how components are connected by cables, e.g., lOBaseT has a star physical topology and FDDI has a double ring physical topology; logical topology refers to how components communicate over a physical topology. Physical and logical topologies are independent of each other; for example, all Ethernet uses a logical bus topology for component communication regardless of which physical topology is used for cabling. This means that in Ethernet, components may be connected in a physical star topology using lOBaseT, but those components communicate in a logical bus topology.Token ring is another communication protocol where the physical topology and logical topology are different. Physically, the token ring uses a star topology like lOBaseT Ethernet, but logically uses a ring topology to communicate between devices. This can be confusing for you when determining how components are connected to each other and how they communicate. FDDI, on the other hand, has no such problems; its physical topology is the same as its logical topology, both ring-shaped. Table 1.2 lists the common media types and their physical and logical topologies.Table 1.2 Examples of Physical and Logical Topologies Media Type Physical Topology Logical Topology