ccna quiz questions

ccna quiz questions.. Limited transmission distance .. Conflicts can occur.The next few subsections will discuss these two issues in depth, while the remainder of this section will describe some of the common solutions available in today's Ethernet.4.1.1 Distance limitations of LANs and their solutionsOne of the problems with the original Ethernet was that the length of the network segment was limited because the medium used was copper: 10Base5 had a maximum transmission distance of 500 meters, while 10Base2 was 185 meters. lOBaseT was first introduced using unshielded twisted pair (UTP), and the maximum transmission distance was further reduced to 100 meters. One of the problems with using copper as a transmission medium is that the signal quality slowly degrades due to noise and signal strength degrades as the signal travels along the copper cable, and some devices do not strictly adhere to the rules defined by CSMA/CD.To cope with the noise and signal strength degradation, one solution is to use a physical layer transponder to forward the signal. In lOBaseT, this function is performed by a hub (multi-port physical layer forwarder); the hub forwards the signals it receives on one interface to all other interfaces. The main problem with hubs is that if the signal is bad, the signal it forwards is also bad: garbage in and garbage out.CSMA/CD can also cause problems. For example, with CSMA/CD, the device puts the frame on the cable and then listens to the cable for a predefined period of time to determine if a conflict has occurred. If no conflict is detected during this time, the source device assumes that all devices in the segment have received the frame. The problem with this implementation is that the longer the cable, the longer it takes for the signal to travel from one section of the cable to the other, so the length of the cable is limited. It is because of this that the various Ethernet standards specify maximum cable lengths. If a device is using a 10Base5 interface, its NIC knows that the duration of the listen must be the time required for the electrical signal to travel 500 meters, regardless of whether the actual length of the cable is 500 meters.Another solution to the Ethernet segment length problem is to use fiber optic cable. Fiber optic cables are much more reliable and transmit signals much faster: for example, lOOBaseFX has a maximum transmission distance of 400 meters. However, the problem with fiber optic cables is that they are more expensive than copper cables, especially for NICs and interface connectors (e.g. SFPs). Typically, fiber optics is used only when connecting equipment located at different field points (e.g., different buildings) or when electromagnetic interference (EMI) and radio frequency interference (RFI) would pose a problem for copper cables.4.1.2 Conflicts, Conflict Domains, and CongestionAnother problem that CSMA/CD presents to Ethernet is that the more devices in a network segment, the greater the potential for conflict, especially when devices often need to access the cable. For example, when there are only two devices on an Ethernet cable, there won't be much conflict because both devices need to