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complements the Cisco Aironet 1200 Series 802.11a Access Point, providing a solution that combines performance and mobility with the security and manageability that enterprises require. The drawback of the 5-GHz frequency, however, is its limited range. Spread-Spectrum Technology. Spread spectrum (SS) is a modulation technique developed in the 1940s that spreads a transmission signal over a broad band of radio...
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Narrowband—This is the opposite of spread spectrum technology. As the name implies, narrowband does not affect the entire frequency spectrum of the wireless signal. Bluetooth technologies hop across the entire 2.4 GHz many times per second and can cause significant interference on an 802.11b network. In homes and offices, a device that is often overlooked as causing interference is the...
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What is the light source typically used in single mode fiber optics?. 1102.book Page 179 Tuesday, May PM. If up to 40 percent of the string is lost, the original transmission can be reconstructed.. The recently released evolution of the IEEE standard, 802.11b, provides for a full Ethernet-like data rate of 11 Mbps over DSSS.. Which of the following is...
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An important concept in communications systems, including LANs, is noise, as shown in Figure 4-5. Although noise usually signifies undesirable sounds, the definition of noise that is related to communications is undesirable signals. Noise can originate from natural and technological sources and is added to the data signals in communications systems.. Even though noise cannot be completely elim- inated, its...
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Figure 4-15 Power Sum Near-End Crosstalk (PSNEXT). Some Ethernet standards, such as 10BASE-T and 100BASE-TX, receive data from only one wire pair in each direction. However, for newer technologies such as 1000BASE-T that receive data simultaneously from multiple pairs in the same direction, power sum measurements are important tests.. All cable links should be tested to the maximum rating that...
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RJ-45—A connector commonly used for finishing a twisted-pair cable. RJ-45. The RJ-45 connector and jack are the most prevalent. RJ-45 connectors are discussed in more detail in the section, “UTP Implementation” later in the chapter.. On 10BASE5 (thicknet) Ethernet, a short cable is used to connect the AUI on the computer with a transceiver on the main cable. In 10BASE2...
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the geographical area past what a single LAN can support, as shown in Figure 4-32.. Switches and bridges operate at the data link layer of the OSI model. The function of the bridge is to make intelligent decisions about whether or not to pass signals on to the next segment of a network. When a bridge receives a frame on...
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Figure 4-41 Client-Server Model. Most client-server systems also include facilities for enhancing the network by adding new services that extend the usefulness of the network.. The distribution of functions in client-server networks brings substantial advantages, but it also incurs some costs. Workstation Workstation Workstation Client-Server Environment. Tables 4-4 and 4-5 summarize the advantages and disadvantages of peer-to-peer versus client-server.. Table...
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To connect an ADSL line to the ADSL port on a router, perform the following simple steps:. Step 1 Connect the phone cable to the ADSL port on the router.. Step 2 Connect the other end of the phone cable to the external wall phone jack.. To connect a router for DSL service, you need a phone cable with RJ-11...
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Which of the following media is used to interconnect the ISDN BRI port to the service-provider device?. What type of connector is used to connect a router and a cable system?. What type of cable is used to connect a terminal and a console port?. Describe briefly the history of Ethernet. Identify the IEEE standards. Identify the common fields of...
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source device sends data out on a network, the data carries the MAC address of its intended destination. As this data propagates along the network medium, the NIC in each device on the network checks to see if its MAC address matches the physical des- tination address carried by the data frame. If there is no match, the NIC discards...
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Networking devices are capable of detecting when a collision has occurred because the amplitude of the signal on the networking media increases (CD = collision detect).. When a collision occurs, each device that is transmitting continues to transmit data for a short time, to ensure that all devices see the collision. When all devices on the net- work have seen...
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reach Station 1, it also truncates the current transmission and substitutes a 32-bit jam signal in place of the remainder of the frame being transmitted. A jam signal can be composed of any binary data, as long as it does not form a proper checksum for the portion of the frame already transmitted. Compared to late collisions, normal collisions are...
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All of the coaxial implementations are inherently half duplex in nature and cannot operate in full duplex. Ethernet has established arbitration rules for resolving conflicts that arise when more than one station attempts to transmit at the same time. Both stations in a point-to-point full-duplex link are permitted to transmit at any time, regardless of whether the other station is...
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Although the numbers in Table 5-7 might appear low, they represent an average, well- designed IP network that is not running the Routing Information Protocol (RIP). So many responses are sent to the original request that the device cannot process them, or the first request triggers similar requests from other devices that effectively block normal traffic flow on the network.....
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Complete all the review questions to test your understanding of the topics and con- cepts in this chapter. Which of the following is not one of the recognized IEEE sublayers?. None of the above. The recognized IEEE sublayers are concerned with what layers of the OSI reference model?. All of the above. What is the name of the access method...
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Manchester encoding relies on the direction of the edge transition in the middle of the timing window to determine the binary value for that bit period. In the encoding exam- ple shown in Figure 6-3, one timing window is highlighted vertically through all four waveform examples. The top waveform has a falling edge in the center of the timing window,...
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In response to these issues of synchronization, bandwidth, and signal-to-noise ratio (SNR), two sepa- rate encoding steps are used by 100-Mbps Ethernet. The first part of the encoding uses a technique called 4-bit/5-bit (4B/5B). the second part of the encoding is the actual line encoding specific to copper or fiber.. The two forms of 100-Mbps Ethernet of consideration in this...
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For 1000BASE-T, the first part of the encoding uses a technique called 8Bit-1Quinary quarter (8B1Q4). the second part of the encoding is the actual line encoding specific to copper, called 4-dimensional 5 level pulse amplitude modulation (4D-PAM5). The 8B1Q4 encoding followed by the 4D-PAM5 line encod- ing provide the synchronization, bandwidth, and SNR characteristics needed to make possible the four...
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The higher speeds and greater transmission dis- tances that are making Ethernet both a LAN and a MAN protocol are not the only additions to the Ethernet standard that we are likely to see. Because fiber is being used as the transmission medium, the likelihood that an error in the data might occur during the passage of the Ethernet packet...