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computer networking
Data Communications and Networking 5th edition Behrouz A. Forouzan - Solutions
What is the maximum number of simultaneous calls in each cell in an IS-136 (D-AMPS) system, assuming no analog control channels?
What are the functions of a mobile switching center?
What is the maximum number of callers in each cell in AMPS?
What is the relationship between a base station and a mobile switching center?
Draw a cell pattern with a frequency-reuse factor of 3.
When we make a wireless Internet connection from our cellular phone, do we use fixed or mobile WiMAX?
Draw a cell pattern with a frequency-reuse factor of 5.
When we make a wireless Internet connection from our desktop at home, do we use fixed or mobile WiMAX?
In Figure 16.5, do we mean that downstream and upstream data are transmitting at the same time? Explain.Figure 16.5 Figure 16.5 WIMAX frame structure at the physical layer UR: Upstream reservation U; Upstream data CR: Connection request DR: Downstream reservation D; Downstream data C: Control DR UR
Explain the differences between a fixed WiMAX and a mobile WiMAX.
Explain how bidirectional communication can be achieved using a frame in Figure 16.5. Figure 16.5
Figure 15.23 shows the frame format of the baseband layer in Bluetooth (802.15). Based on this format, answer the following questions:Figure 15.23a. What is the range of the address domain in a Bluetooth network?b. How many stations can be active at the same time in a piconet based on the
Although an RTS frame defines the value of time that NAV can be effective for the rest of the session, why does the 802.11 project define that other frames used in the session should redefine the rest of the period for NAV?
An 802.11 network may use four different interframe spaces (IFSs) to delay the transmission of a frame in different situations. This allows low-priority traffic to wait for high-priority traffic when the channel becomes idle. Normally, four different IFSs are used in different implementations, as
What is the role of the L2CAP layer in Bluetooth?
In an 802.11 network, there are three stations, A, B, and C. Station C is hidden from A, but can be seen (electronically) by B. Now assume that station A needs to send data to station B. Since C is hidden from A, the RTS frame cannot reach C. Explain how station C can find out that the channel is
What MAC protocol is used in the baseband layer of Bluetooth?
In an 802.11 network, three stations (A, B, and C) are contending to access the medium. The contention window for each station has 31 slots. Station A randomly picks up the first slot; station B picks up the fifth slot; and station C picks up the twenty-first slot. Show the procedure each station
What is the modulation technique in the radio layer of Bluetooth? In other words, how are digital data (bits) changed to analog signals (radio waves)?
In an 802.11 network, station A sends two data fragments to station B. What would be the value of the D field (in microseconds) that needs to be set for the NAV period in each of the following frames: RTS, CTS, data, and ACK? Assume that the transmission time for RTS, CTS, and ACK is 4 μs each.
What is the spread spectrum technique used by Bluetooth?
In an 802.11 network, station A sends one data frame (not fragmented) to station B. What would be the value of the D field (in microseconds) that needs to be set for the NAV period in each of the following frames: RTS, CTS, data, and ACK? Assume that the transmission time for RTS, CTS, and ACK is 4
Fill in the blanks. The 83.5 MHz bandwidth in Bluetooth is divided into_____ channels, each of ______ MHz.
In an 802.11 network, assume station A has four fragments to send to station B. If the sequence number of the first fragment is selected as 3273, what are the values of the more fragment flag, fragment number, and sequence number?
What is the role of the radio layer in Bluetooth?
Both the IP protocol and the 802.11 project fragment their packets. IP fragments a datagram at the network layer; 802.11 fragments a frame at the datalink layer. Compare and contrast the two fragmentation schemes, using the different fields and subfields used in each protocol.
What is the actual bandwidth used for communication in a Bluetooth network?
In an 802.11 communication, the size of the payload (frame body) is 1200 bytes. The station decides to fragment the frame into three fragments, each of 400 payload bytes. Answer the following questions:a. What would be the size of the data frame if no fragmentations were done?b. What is the size of
Can a piconet have more than eight stations? Explain.
Do some research and find out how flow and error control are accomplished in an 802.11 network using the DCF MAC sublayer.
Compare a piconet and a scatternet in the Bluetooth architecture.
A BSS ID (BSSID) is a 48-bit address assigned to a BSS in an 802.11 network. Do some research and find what the use of the BSSID is and how BSSIDs are assigned in ad hoc and infrastructure networks.
What is the reason that Bluetooth is normally called a wireless personal area network (WPAN) instead of a wireless local area network (WLAN)?
In Figure 15.25 (previous problem), assume that the host with IP address 24.12.10.3 needs to send an IP datagram to the host with IP address 128.41.23.12 somewhere in the world (not shown in the figure). Explain the process and show how the values of address 1, address 2, address 3, and address 4
An AP in a wireless network plays the same role as a link-layer switch in a wired network. However, a link-layer switch has no MAC address, but an AP normally needs a MAC address. Explain the reason.
Assume two 802.11 wireless networks are connected to the rest of the Internet via a router as shown in Figure 15.25. The router has received an IP datagram with the destination IP address 24.12.7.1 and needs to send it to the corresponding wireless host. Explain the process and describe how the
An AP may connect a wireless network to a wired network. Does the AP need to have two MAC addresses in this case?
Assume a frame moves from a wireless network using the 802.11 protocol to a wired network using the 802.3 protocol. Show how the field values in the 802.3 frame are filled with the values of the 802.11 frame. Assume that the transformation occurs at the AP that is on the boundary between the two
Do the MAC addresses used in an 802.3 (Wired Ethernet) and the MAC addresses used in an 802.11 (Wireless Ethernet) belong to two different address spaces?
Assume that a frame moves from a wired network using the 802.3 protocol to a wireless network using the 802.11 protocol. Show how the field values in the 802.11 frame are filled with the values of the 802.3 frame. Assume that the transformation occurs at the AP that is on the boundary between the
Write and test a program to simulate the flow diagram of CSMA/CA in Figure 12.15. Figure 12.15 Flow diagram of CSMA/CA Station has a frame to send K = 0 Legend K: Number of attempts T: Backoff time IFS: Interframe Space RTS: Request to send CTS: Clear to send Channel free? [false) [true]
Explain why we have only one frame type in a wired LAN, but four frame types in a wireless LAN.
Repeat the previous problem (Figure 15.24), but assume that the distribution system is also wireless. AP1 is connected to AP2 through a wireless channel. Show the value of addresses in all communication sections: from station A to AP1, from AP1 to AP2, and from AP2 to station C.Figure 15.24 Figure
Write and test a program to simulate the flow diagram of CSMA/CD in Figure 12.13. Figure 12.13 Flow diagram for the CSMA/CD Station has a frame to send K= 0 Legend T Frame average transmission time Wait Tg K: Number of attempts R: (random number): 0 to 2* – 1 TR: (Backoff time) =Rx T Apply
Explain why fragmentation is recommended in a wireless LAN.
In Figure 15.24, two wireless networks, BSS1 and BSS2, are connected through a wired distribution system (DS), an Ethernet LAN. Assume station A in BSS1 needs to send a data frame to station C in BSS2. Show the value of addresses in 802.11 and 802.3 frames for three transmissions: from station A to
Write and test a program that simulates the bit stuffing and bit unstuffing as shown in Figure 11.4. Figure 11.4 Bit stuffing and unstuffing Data from upper layer 0001111111001111101000 Stuffed Frame sent Flag Trailer Flag Header 000111110110011111001000 Two extra bits Frame received Flag
What are some reasons that CSMA/CD cannot be used in a wireless LAN?
In a BSS with no AP (ad hoc network), we have five stations: A, B, C, D, and E. Station A needs to send a message to station B. Answer the following questions for the situation where the network is using the DCF protocol:a. What are the values of the To DS and From DS bits in the frames
Write and test a program that simulates the byte stuffing and byte unstuffing as shown in Figure 11.2. Figure 11.2 Byte stuffing and unstuffing Data from upper layer Flag ESC Sent frame Stuffed Flag ESC Flag ESC ESC Trailer Flag Header Extra Extra byte byte Flag ESC Flag ESC ESC Trailer Flag
What is multipath propagation? What is its effect on wireless networks?
In an 802.11, give the value of the address 4 field in each of the following situations (left bit defines To DS and right bit defines From DS).a. 00b. 01c. 10d. 11
A program to simulate the calculation of Adler checksum.
Why is SNR in a wireless LAN normally lower than SNR in a wired LAN?
In an 802.11, give the value of the address 3 field in each of the following situations (left bit defines To DS and right bit defines From DS).a. 00b. 01c. 10d. 11
A program to simulate the calculation of Fletcher checksum.
Explain why there is more attenuation in a wireless LAN than in a wired LAN, ignoring the noise and the interference.
In an 802.11, give the value of the address 2 field in each of the following situations (left bit defines To DS and right bit defines From DS).a. 00b. 01c. 10d. 11
A program to simulate the calculation of traditional checksum.
Explain why the MAC protocol is more important in wireless LANs than in wired LANs.
In an 802.11, give the value of the address 1 field in each of the following situations (left bit defines To DS and right bit defines From DS).a. 00b. 01c. 10d. 11
A program to simulate the calculation of CRC.
Compare the medium of a wired LAN with that of a wireless LAN in today’s communication environment.
How many virtual connections can be defined in a UNI? How many virtual connections can be defined in an NNI?
Name the ATM layers and their functions.
How is an ATM virtual connection identified?
What is the relationship between TPs, VPs, and VCs?
How does an NNI differ from a UNI?
Why is multiplexing more efficient if all the data units are the same size?
In ATM, what is the relationship between TPs, VPs, and VCs?
What is a virtual tributary?
Discuss the functions of each SONET layer.
What is the minimum number of cells resulting from an input packet in the AAL5 layer? What is the maximum number of cells resulting from an input packet?
What are the four SONET layers?
A stream of data is being carried by STS-1 frames. If the data rate of the stream is 49.530 Mbps, how many frames per second should leave one empty byte after the H3 byte?
What is the function of a SONET regenerator?
A stream of data is being carried by STS-1 frames. If the data rate of the stream is 49.540 Mbps, how many STS-1 frames per second must let their H3 bytes carry data?
Why is SONET called a synchronous network?
Show how STS-9s can be multiplexed to create an STS-36. Is there any extra overhead involved in this type of multiplexing?
What is the purpose of the pointer in the line overhead?
What are the user data rates of STS-3, STS-9, and STS-12?
What is the relationship between STS signals and OC signals?
What type of topology is used when customers in an area use DSL modems for data transfer purposes? Explain.
How is an STS multiplexer different from an add/drop multiplexer since both can add signals together?
What type of topology is used when customers in an area use cable modems for data transfer purposes? Explain.
What is the relationship between STS and STM?
What type of topology is used when customers in an area use DSL modems for data transfer purposes? Explain.
What is the relationship between SONET and SDH?
Repeat Problem P14-7 using a cable modem (consider the minimum rates).Problem P14-7Calculate the minimum time required to download one million bytes of information using a 56K modem.
Distinguish between CM and CMTS.
Repeat Problem P14-7 using ADSL implementations (consider the minimum rates).Problem P14-7Calculate the minimum time required to download one million bytes of information using a 56K modem.
How is data transfer achieved using CATV channels?
Calculate the minimum time required to download one million bytes of information using a 56K modem.
Compare and contrast a traditional cable network with a hybrid fiber-coaxial network.
Draw a bar chart to compare the different downloading data rates of common DSL technology implementations (use minimum data rates).
What is DSL technology? What are the services provided by the telephone companies using DSL? Distinguish between a DSL modem and a DSLAM.
Draw a bar chart to compare the different downloading data rates of common modems.
What is dial-up modem technology? List some of the common modem standards discussed in this chapter and give their data rates.
When we have an overseas telephone conversation, we sometimes experience a delay. Can you explain the reason?
What are the two major services provided by telephone companies in the United States?
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![Figure 12.15 Flow diagram of CSMA/CA Station has a frame to send K = 0 Legend K: Number of attempts T: Backoff time IFS: Interframe Space RTS: Request to send CTS: Clear to send Channel free? [false) [true] Carrier sense Wait IFS Choose a random number R between 0 and](https://dsd5zvtm8ll6.cloudfront.net/si.question.images/images/question_images/1607/3/4/6/6795fce29f7e0ef81607346678411.jpg)
