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TCP/IP QUESTION BANK VII Semester B.E. CSE Sub: TCP/IP & INTERNET 1. How are the OSI and ISO related to each other. 2. Match the following to one or more layer of the OSI model a. route determination b. flow control c. interface to transmission media d. provide access for the end user 3. Match t...

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TCP/IP QUESTION BANK

VII Semester B.E. CSE Sub: TCP/IP & INTERNET

1. How are the OSI and ISO related to each other. 2. Match the following to one or more layer of the OSI model a. route determination b. flow control c. interface to transmission media d. provide access for the end user 3. Match the following to one or more layer of the OSI model a. reliable process to process message delivery b. route selection c. defines frames d. provide user services such as email and file transfer e. transmission of bit stream across physical medium 4. Match the following to one or more layer of the OSI model a. communicates directly with users application program b. error correction and retransmission c. mechanical, electrical and functional interface d. responsibility of carrying frames between adjacent nodes 5. Match the following to one or more layer of the OSI model a. format an code conversion services b. establishes, manages and terminates sessions c. ensures reliable transmission of data d. log-in and log-out procedures e. provide independence from differences in data representation 6. Why do you think that an Ethernet frame should have minimum data size. 7. Imagine the length of a 10BASE5 cable is 2500 meters. If the speed of propagation in a thick coaxial cable is 200,000,000 meters/second, how long does it take for a bit to travel from the beginning to the end of the network? Ignore any propagation delay in the network. 8. The data rate of 10BASE5 is 10 Mbps. How long does it take to create the smallest frame 9. An Ethernet MAC sub layer receives 42 bytes of data from the LLC sub layer. How many bytes of padding must be added to data. 10. Compare and contrast CSMA/CD with CSMA/CA 11. What is the address space in each of the following systems

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TCP/IP QUESTION BANK a. a system with 8-bit addresses b. a system with 16-bit addresses c. a system with 64 bits addresses 12. An address space has a total of 1024 addresses. How many bits are needed to represent an address. 13. An address space uses three symbols: 0, 1 and 2 represent addresses. If each address is made of 10 symbols, how many addresses are available in this system. 14. Change the following IP addresses from dotted-decimal notation to binary notation a. 114.34.2.8 b. 129.14.6.8 c. 208.34.54.12 d. 238.34.2.1 e. 241.34.2.8 15. Change the following IP addresses from dotted-decimal notation to hexadecimal notation a. 114.34.2.8 b. 129.14.6.8 c. 208.34.54.12 d. 238.34.2.1 e. 241.34.2.8 16. Change the following IP addresses from hexadecimal notation to binary notation. a. 0x1347FEAB b. 0xAB234102 c. 0x0123A2BE d. 0x00001111 17. How many digits are needed to define the netid in hexadecimal notation in each of the following classes a. Class A b. Class B c. Class C 18. Find the class of following IP addresses: a. 208.34.54.12 b. 238.34.2.1 c. 114.34.2.8 d. 129.14.6.8 e. 241.34.2.8 19. Find the class of following IP addresses a. 11110111 11110011 10000111 11011101 b. 10101111 11000000 11110000 00011101 c. 11011111 10110000 00011111 01011101 d. 11101111 11110111 11000111 00011101 e. 01111111 11110000 01100111 01111101 20. Find the netid an hostid of the following IP addresses: a. 114.34.2.8 b. 132.56.8.6

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TCP/IP QUESTION BANK c. 208.34.54.12 21. A host with IP address 128.23.67.3 sends a message to a host with IP address 193.45.23.7 Does the message travel through any router? Assume no subneting. 22. A host with IP address 128.23.67.3 sends a message to a host with IP address 128.45.23.7 Does the message travel through any router? Assume no subneting. 23. A host with IP address 128.23.67.3 sends a message to a host with IP address 128.23.23.7. Does the message travel through any router? Assume no subneting. 24. Draw a diagram of a network with address 8.0.0.0 that is connected through a router to a network with IP address 131.45.0.0. Choose IP addresses for each interface of the router. Show also some hosts on each network with their IP addresses. What is the class of each network. 25. A router has an IP address of 108.5.18.22 It sends a direct broadcast packet to all hosts in this network. What are the source and destination IP addresses used in this packet. 26. A host with IP address 108.67.18.70 sends a limited broadcast packet to all hosts in the same network. What are the source and destination IP addresses used in this packet. 27. A host with IP address 185.67.89.34 needs loopback testing. What are the source and destination addresses. 28. A host with IP address 123.27.19.24 sends a message to a host with IP address 123.67.89.56 using the “Specific Host on This Network” special address. What are the source and destination addresses. 29. A host in a class C that does not know its IP address wants to send a message to a bootstrap server to find its address. What are the source and destination addresses. 30. Can we have an address such as x.y.z.t/32? Explain. 31. In class A, the first address in a network is 20.0.0.0. What is the 220000th address? Hint: use the base 256 numbering system. 32. In a network, the address of one computer is 201.78.24.56 and the address of another computer is 201.78.120.202. How many addresses are in between. 33. In a class A subnet, we know the IP address of one of the hosts and the mask as given below: IP Address: 25.34.12.56 Mask: 255.255.0.0 What is the first address (subnet address) 34. In a class B subnet, we know the IP address of one of the hosts and the mask as given below: IP Address: 125.134.112.66 Mask: 255.254.0.0 What is the first address (subnet address) 35. In a class C subnet, we know the IP address of one of the hosts and the mask as given below: IP Address: 182.44.82.16 Mask: 255.255.255.192 What is the first address (subnet address) 36. Find the contiguous mask in each case a. 1024 subnets in class A b. 256 subnets in Class C

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TCP/IP QUESTION BANK c. 32 subnets in class C d. 4 subnets in class C 37. What is the maximum number of subnets in each case. a. Class A: mask 255.255.192.0 b. Class B: mask 255.255.192.0 c. Class C: mask 255.255.255.192 d. Class D: mask 255.255.255.240 38. In a block of addresses, we know the IP address of one host is 25.34.12.56/16. What is the first address and the last address in this block. 39. In a block of addresses, we know the IP address of one host is 182.44.82.16/26. What is the first address and the last address in this block. 40. In a fixed-length subnetting, find the number of 1s that must be added to the mask if the number of desired subnets is__________ 2, 62, 122, 250 41. What is the maximum number of subnets if the prefix length of a block is a. 18 b. 10 c. 27 d. 31 42. An organization is granted the block 16.0.0.0/8. The administrator wants to create 500 fixed-length subnets. a. Find the subnet mask. b. Find the number of addresses in each subnet. c. Find the first and the last address in the first subnet d. Find the first and the last address in the last subnet 43. An organization is granted the block 130.56.0.0/16. The administrator wants to create 1024 subnets. a. Find the subnet mask. b. Find the number of addresses in each subnet. c. Find the first and the last address in the first subnet d. Find the first and the last address in the last subnet 44. An organization is granted the block 211.17.180.0/24. The administrator wants to create 32 subnets. a. Find the subnet mask. b. Find the number of addresses in each subnet. c. Find the first and the last address in the first subnet d. Find the first and the last address in the last subnet ( subnet 32) 45. Write the following mask in slash notation (/n): a. 255.255.255.0 b. 255.0.0.0 c. 255.255.224.0 d. 255.255.240.0 46. Find the range of addresses in the following blocks: a. 123.56.77.32/29

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TCP/IP QUESTION BANK b. 200.17.21.128/27 c. 17.34.16.0/23 d. 180.34.64.64/30 47. An ISP is granted a block of addresses starting with 150.80.0.0/16. The ISP wants to distribute these blocks to 1000 customers as followes: a. The first group has 200 medium-size businesses; each needs 128 addresses b. The second group has 400 small businesses; each needs 16 addresses c. The third group has 2000 households; each needs 4 addresses. Design the subblocks and give the slash notation for each subblock. Find out how many addresses are still available after these allocations. 48. An ISP is granted a block of addresses starting with 120.60.4.0/20. The ISP wants to distribute these blocks to 100 organizations with each organization receiving 8 addresses only. Design the subblocks and give the slash notation for each subblocks. Find out how many addresses are still available after these allocations. 49. An ISP has a block of 1024 addresses. It needs to divide the addresses to 1024 customers, does it need subnetting? Explain your answer. 50. A host with IP address 137.23.56.23/16 sends a packet to a host with IP address 137.23.67.9/16. Is the delivery direct or indirect? Assume no subnetting. 51. A host with IP address 137.23.56.23/16 sends a packet to a host with IP address 142.3.6.9/24. Is the delivery direct or indirect? Assume no subnetting. 52. Is the size of ARP packet fixed? Explain. 53. Is the size of RARP packet fixed? Explain. 54. What is the size of an ARP packet when the protocol is IP and the hardware is Ethernet? 55. What is the size of an RARP packet when the protocol is IP and the hardware is Ethernet? 56. What is the size of an Ethernet frame carrying an ARP packet. 57. What is the size of an Ethernet frame carrying an RARP packet. 58. What is the broadcast address for Ethernet. 59. A router with IP address 125.45.23.12 and Ethernet physical address 23:45:AB:4F:67:CD has received a packet for a host destination with IP address 125.11.78.10 and Ethernet physical address AA:BB:A2:4F:67:CD. Show the entries in the ARP request packet sent by the router. Assume no subnetting. 60. Show the entries in the ARP packet sent in response to above exercise. 61. A router with IP address 195.5.2.12 and Ethernet physical address AA:25:AB:1F:67:CD has received a packet for a destination with IP address 185.11.78.10. When the router checks its routing table, it finds out the packet should be delivered to a router with IP address 195.5.2.6 and Ethernet physical address AD:34:5D:4F:67:CD. Show the entries in the ARP request packet sent by the router. Assume no subnetting. 62. A diskless host with an Ethernet physical address 98:45:23:4F:67:CD has been booted. Show the entries in the RARP packet sent by this host. 63. Encapsulate the result of above exercise in a data link frame. Fill in all the fields. 64. Which fields of the IP header change from router to router. 65. Calculate the HLEN value if the total length is 1200 bytes, 1176 of which is data from the upper layer. 66. Given a fragmented datagram with an offset of 120, how can you determine the first and the last byte number.

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TCP/IP QUESTION BANK 67. An IP datagram must go through router 128.46.10.5. There are no other restrictions on the routers to be visited. Draw the IP options with their values. 68. What is the maximum number of routers that can be recorded if the timestamp option has a flag value of 1? Why? 69. Can the value of the header length in an IP packet be less than 5? When is it exactly 5? 70. The value of HLEN in an IP datagram is 7. How many option bytes are present. 71. The size of the option field of an IP datagram is 20 bytes. What is the value of HLEN? What is the value in binary. 72. The value of the total length field in an IP datagram is 36 and the value of the header length field is 5. How many bytes of data is the packet carrying. 73. A datagram is carrying 1024 bytes of data. If there is no option information, what is the value of the header length field? What is the value of the total length field. 74. A host is sending 100 datagram’s to another host. If the identification number of the first datagram is 1024, what is the identification number of the last. 75. An IP datagram arrives with fragmentation offset of 0 and M bit of 0. Is this a first fragment, middle fragment or last fragment. 76. An IP fragment has arrived with an offset value of 100. How many bytes of data were originally sent by the source before the data in this fragment. 77. An IP datagram has arrived with the following information in the header (in hexadecimal): 45 00 00 54 00 03 00 00 20 06 00 00 7C 4E 03 02 B4 0E 0F 02 a. Are there any options b. Is the packet fragmented c. Is a checksum used d. How many more routers can the packet travel to e. What is the identification number of the packet. f. What is the type of service. 78. In a datagram, the M bit is zero, the value of HLEN is 5, the value of total length is 200, and the offset value is 200. What is the number of the first byte and number of the last byte in this datagram? Is this the last fragment, the first fragment, or a middle fragment. 78. Host A sends a timestamp-request message to host B and never receives a reply. Discuss three possible causes and the corresponding course of action. 79. Why is there a restriction on the generation of an ICMP message in response to a failed ICMP error message. 80. Host A sends a datagram to host B. Host B never receives the datagram and host A never receives notification of failure. Give two different explanations of what might have happened. 81. What is the purpose of including the IP header and the first 8 bytes of datagram data in the error reporting ICMP messages. 82. What is the maximum value of the pointer field in a parameter-problem message. 83. Give an example of a situation in which a host would never receive a redirection message. 84. Make a table showing which ICMP messages are sent by routers, which are sent by nondestination hosts, and which are sent by destination hosts.

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TCP/IP QUESTION BANK 85. Can the calculated sending time, receiving time, or round-trip time have a negative value? Why or why not? Give examples. 86. Why isn’t the one way time for a packet simply the round-trip time divided by two. 87. What is the minimum size of an ICMP packet? What is the maximum size of an ICMP packet. 88. What is the minimum size of an IP packet that carries an ICMP packet? What is the maximum size. 89. What is the minimum size of an Ethernet frame that carries an IP packet which in turn carries an ICMP packet? What is the maximum size. 90. How can we determine if an IP packet is carrying an ICMP packet. 91. Calculate the checksum for the following ICMP packet: Type: Echo Request Identifier: 123 Sequence Number: 25 Message: Hello 92. A rooter receives an IP packet with source IP address 130.45.3.3 and destination IP I address 201.23.4.6. The router cannot find the destination IP address in its routing I table. Hill in the fields (as much as you can) for die ICMP message sent 93. TCP receives a segment with destination port address 234. TCP checks and cannot I rind an open port for this destination. Fill in the fields for the ICMP message sent I 94. An ICMP message has arrived with the header (in hexadecimal): 03O31O2OO00000OO What is the type of the message? What is the code*? What is the purpose of the message? 95. An ICMP message has arrived with the header (in hexadecimal): 05 0011 12 II 0B 0302 What is the type of the message? What is the code? What is the purpose of the message? What is the value of the last 4 bytes? What do the last bytes signify? 96. A compute sends a timestamp request. If its clock shows 5:20:30 A.M. (Universal Time), show the entries for the message. 97. A computer receives a timestamp request from another computer at 2:34:20 P.M the value of the original timestamp is 52.453,000. If the sender clock is 5 ms slow, 1 what is the oneway time? 98. A computer sends a timestamp request to another computer; it receives the spending timestamp reply at 3:46:07 A.M. The values of the original timestamp receive timestamp, and transmit timestamp are 13,560,000. 13,562,000, and 13,564.300. respectively. What is the sending trip time? What is the receiving time? What is the round-trip time? What is the difference between the sender clock and the receiver clock? 100. If two computers are 5000 miles apart, what is the minimum time for messages to go from one to the other? 101. Why is there no need for the IGMP message to travel outside its own network? 102.

A multicast router list contains four groups (W, X, Y, and Z). There are three hosts on the LAN. Host A has three loyal members belonging to group W and one loyal member belonging to

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TCP/IP QUESTION BANK

103. 104. 105. 106. 107. 108. 109.

110. 111.

112. 113. 114.

115.

116.

117. 118.

119. 120.

group X. Host B has two loyal members belonging to group W and one loyal member belonging to group Y. Host C has no processes belonging to any group. Show the IGMP messages involved in monitoring. A multicast address for a group is 231.24.60.9. What is its 48-bit Ethernet address for a LAN using TCP/IP? If a router has 20 entries in its group table, should it send 20 different queries periodically or just one? Explain your answer. If a host wants to continue membership in five groups, should it send five different membership report messages or just one? A router with IP address 202.45.33.21 and physical Ethernet address 23:4A: 45:12:EC: D1 sends an IGMP general query message. Show all of the entries in the message. Encapsulate the message of Exercise 6 in an IP packet. Fill in all the fields. Encapsulate the message of Exercise 7 in an Ethernet frame. Fill in all the A host with IP address 124.15.13.1 and physical Ethernet address 4A: 22:45:12:E1:E2 sends an IGMP membership report message about groupid 228.45.23.11. Show all of the entries in the message. Encapsulate the message of Exercise 10 in an Ethernet frame. Fill in all the fields A router on an Ethernet network has received a multicast IP packet with group i 226.17.18.4. When the host checks its multicast group table, it finds this address Show how the router sends this packet to the recipients by encapsulating the IP packet in an Ethernet frame. Show all of the entries of the Ethernet frame. The outgoing IP address of the router is 185.23.5.6 and its outgoing physical address is 4A224512E1E2. Does the router need the services of ARP? What if the router in Exercise 12 cannot find the groupid in its table? Redo Exercise 12 with a physical network that does not support physical multicast addressing. A host with IP address 114.45.7.9 receives an IGMP query. When it checks its group table, it finds no entries. What action should the host take? Should it send any messages? If so, show the packet fields. A host with IP address 222.5.7.19 receives an IGMP query. When it checks its routing table, it finds two entries in its table: 227.4.3.7 and 229.45.6.23. What action should the host take? Should it send any messages? If so, what type and how many? Show the fields. A host with IP address 186.4.77.9 receives a request from a process to join a group with groupid 230.44.101.34. When the host checks its group table, it does not find an entry for this groupid. What action should the host take? Should it send any messages? If so, show the packet field Redo Exercise 17 with the host finding an entry in its table. A router with IP address 184.4.7.9 receives a report from a host that wants to join a group with groupid 232.54.10.34. When the router checks its group table, it does not find an entry for this groupid. What action should the router take? Should it send any messages? If so, show the packet fields. Redo Exercise 19 with the router finding an entry in its table. A router sends a query and receives only three reports about groupids 225.4.6.7, 225.32.56.8, and 226.34.12.9. When it checks its routing table, it finds five entries:

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TCP/IP QUESTION BANK

121.

225.4.6.7, 225.11.6.8, 226.34.12.9, 226.23.22.67, and 229.12.4.89. What action should be taken? The contents of an IGMP ...