1: Your junior network administrator wants to know what the default subnet mask is for a Class C IP address. What do you tell him?
A. 255.0.0.0
B. 255.255.0.0
C. 255.245.255.0
D. 255.255.255.0
E. 255.255.255.255
2: An application needs to have reliable, end-to-end connect-ivity. Which of the following protocols will give you reliable connectivity?
A. TCP
B. UDP
C. IP
D. ICMP
3: You are designing a network, which needs to support 55 users. You don't plan to extend the segment beyond the current number of users. Which subnet mask would best meet your needs?
A. 255.255.0.0
B. 255.255.255.0
C. 255.255.255.192
D. 255.255.255.160
4: You have added a new switch to your network. You want to manage it remotely, so you need to assign it an IP address. Your router that connects to the switch has an IP address of 172.16.12.33/27. Which of the following addresses can you assign to this switch?
A. 172.16.12.33/28
B. 172.16.12.32/27
C. 172.16.12.33/27
D. 172.16.12.34/27
E. 172.16.12.35/28
F. 172.16.12.38/28
G. 172.16.12.63/27
5: The address 172.16.208.16/20 is a host address in which of the following subnets?
A. 172.16.176.0–255.255.240.0
B. 172.16.192.0–255.255.240.0
C. 172.16.208.0–255.255.240.0
D. 172.16.224.0–255.255.240.0
6: You are designing an IP address scheme for your brand new remote office. The vice president of IT calls to tell you that you will be in charge of the 192.168.1.64/26 subnetwork. This supplies you with a single subnetwork with 62 hosts. You need to have at least two subnets with 14 hosts in each subnet. What custom subnet mask should you use?
A. 255.255.255.128
B. 255.255.255.192
C. 255.255.255.224
D. 255.255.255.240
E. 255.255.255.248
7: You have subnetted the 210.106.14.0 network with a /24 mask. Your boss at Acme, Inc. wants to know how many usable subnetworks and usable host addresses per subnet this would provide. What should you tell her?
A. One network with 254 hosts
B. Two networks with 128 hosts
C. Four networks with 64 hosts
D. Six networks with 30 hosts
8: Identify three valid host addresses in any subnet of the 201.168.27.0 network, assuming a fixed subnet mask of 255.255.255.240. (Choose three.)
A. 201.168.27.33
B. 201.168.27.112
C. 201.168.27.119
D. 201.168.27.126
E. 201.168.27.175
F. 201.168.27.208
9: What is the subnetwork address for a host with the IP address 201.100.5.68/28?
A. 201.100.5.0
B. 201.100.5.32
C. 201.100.5.64
D. 201.100.5.65
E. 201.100.5.31
F. 201.100.5.1
10: Which of the following protocols uses a three-way handshake mechanism to establish sessions?
A. TCP
B. IP
C. UDP
D. IPX
E. Frame relay
11: Which of the following protocols is connection-oriented?
A. TCP
B. IP
C. IPX
D. Frame relay
12: You are using an application on your Windows 2000 client machines that provides error correction. You need a protocol to provide fast transport. Which protocol should your application use?
A. TCP
B. IP
C. UDP
D. SPX
E. AppleTalk
13: When using TCP, after a session is open, the applications can adjust the number of segments they receive before sending an acknowledgment. This behavior is known as ______________.
A. MTU adjustment
B. Windowing
C. Flexible Send Path
D. FCS
14: If the destination did not receive a segment, how will the TCP host know to resend the information?
A. The ACK received will not include the segment number that was not received.
B. The ACK received will include the segment number that was not received.
C. The sending host will send a PACK to verify segment receipt.
D. The destination host will send a YACK message back to the sending host.
15: You are planning on using a single network that supports 208 users. Which IP address class would you choose to be the most efficient?
A. Class A
B. Class B
C. Class C
D. Class D
E. Class E
16: RFC 1918 defines the private IP address ranges. Which of the following IP addresses are considered part of these ranges? (Choose three.)
A. 10.23.45.67
B. 126.21.34.56
C. 172.16.32.1
D. 172.31.234.55
E. 192.169.4.5
17: A new network is being designed for your company, Acme, Inc. If you use a Class C IP network, which subnet mask will provide one usable subnet per department while allowing enough usable host addresses for each department specified in the table?
Department
Number of Users
Corporate
7
Customer Support
15
Financial
13
HR
7
Engineering
16
A. 255.255.255.0
B. 255.255.255.192
C. 255.255.255.224
D. 255.255.255.240
E. 255.255.255.248
18: Which of these protocols provides data transport, relying on the error correction capabilities of the application itself?
A. UDP
B. TCP
C. SNMP
D. ICMP
19: Which of the following are used by TCP to ensure reliable delivery of data? (Choose two.)
A. MAC address resolution
B. Sequence numbers
C. Acknowledgments
D. Ping
E. Routing updates
20: You discover that you are able to adjust the window size of the TCP segment. You increase the window size to test the results. What will you observe happening on your network?
A. Increased throughput
B. Decreased throughput
C. Increased latency
D. Decreased reliability
21: Your organization is using the 192.168.1.0/24 address space. You need 28 subnets. What subnet mask would you use to create these subnets?
A. 255.255.255.0
B. 255.255.255.128
C. 255.255.255.192
D. 255.255.255.224
E. 255.255.255.240
F. 255.255.255.248
22: Which of the following protocols maps IP addresses to MAC addresses for connectivity to occur between two hosts?
A. ARP
B. RARP
C. SLARP
D. DHCP
23: Your junior network administrator cannot seem to ping a host in another network and asks you why it isn't working. Which of the following is not an answer that you would give him?
A. The host's default gateway is down.
B. The destination host is not powered on.
C. The IP address of the router interface is incorrect.
D. The IP address of the switch to which the destination host connects is incorrect.
E. The host is in a different subnet.
24: Which of the following classes of IP addresses is utilized for multicasting?
A. Class A
B. Class B
C. Class C
D. Class D
25: You give your IT department a spreadsheet of IP addresses and their subnets. You receive a call from one of the junior techs asking what the /26 means next to the IP addresses. You tell her:
A. It represents the number of hosts possible on that subnetwork.
B. It represents the number of subnetworks that are being used.
C. It represents the class of IP address being used.
D. It represents the number of bits in the subnet mask that are 1.
26: You are given an IP network of 192.168.5.0 and told that you need to separate this network into subnetworks that can support a maximum of 16 hosts per subnet. This will help alleviate congestion on the network. What subnet mask can you use to create the subnets necessary to meet the given criteria?
A. 255.0.0.0
B. 255.255.0.0
C. 255.255.255.0
D. 255.255.255.224
E. 255.255.255.240
27: Which of the following would a Class A network be assigned to?
A. Government agency
B. Small-to-medium sized corporation
C. SOHO
D. An individual
28: A client has the IP address 192.168.5.98/27. Which of the following addresses are on the same subnet as this host? (Choose two.)
A. 192.168.5.95
B. 192.168.5.100
C. 192.168.5.128
D. 192.168.5.110
29: Which of the following IP addresses is not a public IP address that can be routed over the Internet?
A. 2.3.4.5
B. 11.12.13.14
C. 165.23.224.2
D. 172.31.45.34
E. 203.33.45.22
30: You are given a Class B network. What is the default subnet mask assigned to the Class B network?
A. 255.255.255.255
B. 255.255.0.0
C. 255.224.0.0
D. 0.0.0.0
31: You are troubleshooting your router's interfaces. For some reason, the Ethernet interface will not accept the IP address of 192.168.5.95/27 that you've assigned. Which of the following explains the router's refusal to take the IP address?
A. Class C addresses cannot be assigned to Ethernet interfaces.
B. The /27 is an invalid mask.
C. It is a broadcast address.
D. It is a public IP address.
E. It is a private IP address.
32: You are a network technician at Acme, Inc. You are required to divide the 172.12.0.0 network into subnets. Each subnet must have the capacity of 458 IP addresses. Also, according to the requirements, you must provide the maximum number of subnets. Which subnet mask should you use?
A. 255.255.255.254
B. 255.255.254.0
C. 255.255.240.254
D. 255.255.0.0
33: What is the subnetwork and broadcast IP address of 192.168.2.37 with the subnet mask of 255.255.255.248?
A. 192.168.2.24/192.168.2.31
B. 192.168.2.32/192.168.2.39
C. 192.168.2.40/192.168.2.47
D. 192.168.2.48/192.168.2.55
E. 192.168.2.56/192.168.2.63
34: One of your co-workers at Acme, Inc., needs to convert the binary number 11011010 into a decimal. What is the decimal equivalent?
A. 218
B. 219
C. 220
D. 221
E. 222
35: One of your co-workers at Acme, Inc., needs to convert the binary number 01011010 into a decimal. What is the decimal equivalent?
A. 75
B. 83
C. 90
D. 97
36: One of your co-workers at Acme, Inc., needs to convert the binary number 11010110 into a decimal. What is the decimal equivalent?
A. 198
B. 214
C. 252
D. 255
37: One of your co-workers at Acme, Inc., needs to convert the binary number 10110110 into a decimal. What is the decimal equivalent?
A. 182
B. 192
C. 202
D. 212
38: You are configuring a subnet for the Acme, Inc., branch office in Beijing. You need to assign IP addresses to hosts in this subnet. You have been given the subnet mask of 255.255.255.224. Which of these IP addresses would be valid? (Choose three.)
A. 15.234.118.63
B. 92.11.178.93
C. 134.178.18.56
D. 192.168.16.87
E. 201.45.116.159
F. 217.63.12.192
39: You are a network technician at Acme, Inc. You have subnetted the 208.98.112.0 network with a /28 mask. Your boss asks you how many usable subnetworks and usable host addresses per subnet this will provide. What should you tell her, assuming your router is using ip subnet-zero?
A. 62 networks and 2 hosts
B. 6 networks and 30 hosts
C. 8 networks and 32 hosts
D. 16 networks and 16 hosts
E. 16 networks and 14 hosts
40: What is a disadvantage of using a connection-oriented protocol such as TCP?
A. Packet acknowledgment might add overhead.
B. Packets are not tagged with sequence numbers.
C. Loss or duplication of data packets is more likely to occur.
D. The application layer must assume responsibility for the correct sequencing of the data packets.
41: You are a network technician at Acme, Inc. You have subnetted the 192.168.72.0 network with a /30 mask for connections between your routers. Your boss asks you how many usable subnetworks and usable host addresses per subnet this will provide. What should you tell her, assuming your router cannot use ip subnet-zero?
A. 62 networks and 2 hosts
B. 6 networks and 30 hosts
C. 8 networks and 32 hosts
D. 16 networks and 16 hosts
E. 14 networks and 14 hosts
42: Which of the following IP addresses are considered "network" addresses with a /26 prefix? (Choose two.)
A. 165.203.2.0
B. 165.203.5.192
C. 165.203.6.63
D. 165.203.6.191
E. 165.203.8.255
43: Identify three valid hosts in any subnet of 192.168.32.0, assuming the subnet mask used is 255.255.255.240. (Choose three.)
A. 192.168.32.33
B. 192.168.32.112
C. 192.168.32.119
D. 192.168.32.126
E. 192.168.32.175
F. 192.168.32.208
44: A Class C network address has been subnetted with a /27 mask. Which of the following addresses is a broadcast address for one of the resulting subnets?
A. 198.57.78.33
B. 198.57.78.64
C. 198.57.78.97
D. 198.57.78.97
E. 198.57.78.159
F. 198.57.78.254
45: What is the subnetwork address for a host with IP address 165.100.5.68/28?
A. 165.100.5.0
B. 165.100.5.32
C. 165.100.5.64
D. 165.100.5.65
E. 165.100.5.31
F. 165.100.5.1
46: Your boss wants to know what TCP stands for. What do you tell him?
A. Transmission Check Protocol
B. Transport Check Protocol
C. Transmission Control Protocol
D. Transport Control Protocol
47: Your boss wants to know what UDP stands for. What do you tell him?
A. Unreliable Data Protocol
B. Unreliable Data Program
C. User-Defined Protocol
D. User Datagram Protocol
48: Which of the following statements accurately describes UDP?
A. UDP copies files between a computer and a system running rshd, the remote shell service (daemon).
B. UDP is a member of the TCP/IP suite of protocols that governs the exchange of electronic mail between message transfer agents.
C. UDP is a member of the TCP/IP suite of protocols and is used to copy files between two computers on the Internet. Both computers must support their respective roles: one must be a client, and the other a server.
D. UDP is a TCP complement that offers a connectionless datagram service guaranteeing neither delivery nor correct sequencing of delivered packets (much like IP).
49: Which of the following host addresses are members of networks that can be routed across the public Internet? (Choose three.)
A. 10.20.12.64
B. 172.16.32.129
C. 172.64.32.34
D. 192.168.23.252
E. 196.104.12.95
F. 214.192.48.254
50: You are connecting your Serial 0/1 interface to the Internet. Which of the following need to be done for the connection to work? (Choose two.)
A. Assign a public IP address.
B. Use the shutdown command.
C. Use the no shutdown command.
D. Make sure the interface is running in full-duplex.
Busines
Hiburan
Showing posts with label TCP/IP Addresing. Show all posts
Showing posts with label TCP/IP Addresing. Show all posts
11:21 AM
Chapter 2. TCP/IP Addressing and Protocol
11:19 AM
Answers and Explanations
A1: Answer: D. The default subnet mask for Class C is 255.255.255.0. A is incorrect, as it is the default mask for Class A. B is incorrect, as it is the default mask for Class B. C is incorrect, as this is not a valid mask. Subnet masks must be consecutive ones. E is not correct, as it is the subnet mask of all ones.
A2: Answer: A. Transmission Control Protocol (TCP) provides reliable end-to-end connectivity, along with error-detection capabilities. B is incorrect, as UDP does not provide any reliability. C is incorrect, as IP does not provide reliability. D is incorrect, as ICMP is used to help troubleshoot TCP/IP connections.
A3: Answer: C. This particular subnet mask allows for up to 62 hosts per network. A is incorrect, as it allows for 65,534 hosts. B is incorrect, as it allows up to 254 hosts. D is incorrect, as it is not a valid subnet mask.
A4: Answer: D. The next valid IP host address in the 172.16.12.32 network is 172.16.12.34. A is incorrect, as it is on a different subnetwork with a /28 mask. B is incorrect, as it is the network address for that particular subnetwork. C is incorrect, as it is the same IP address as the router interface. E and F are incorrect as well, as they are on different subnets than the router interface. Choice G is incorrect because it represents the broadcast address for the 172.16.12.32 subnetwork and cannot be used as a host address.
A5: Answer: C. The network address for the IP address is 172.16.208.0–255.255.240.0. A, B, and D are incorrect, as they are different subnetworks.
A6: Answer: D. This subnet mask gives you two additional subnets using VLSM, with up to 14 hosts per subnetwork. A is incorrect, as it is a higher subnet mask than your original /26, which is actually called supernetting. B is incorrect because it is your original subnet mask. C is incorrect, as it does not give you enough subnets. E is incorrect, as it gives you enough subnets (six), but you would have only six hosts.
A7: Answer: A. You have actually not done any subnetting with a /24 mask; it is the default Class C subnet mask of 255.255.255.0. This gives you one network with 254 possible hosts. B, C, and D are incorrect because you have not borrowed any bits to create subnetworks.
A8: Answers: A, C, and D. A subnet mask of 255.255.255.240 divides the fourth octet into subnet parts: the highest four bits and a host port (the lowest four bits). You simply check the fourth octet to ensure that all subnet and host parts are okay. The host bit portion cannot be 0000 or 1111. A, C, and D are correct because 33 in decimal is 00100001, 119 in decimal is 01110111, and 126 in decimal is 1111110. B is incorrect, as 112 in decimal is 1110000 in binary. This is not a valid host address in this network. All its host bits are zero. E is incorrect, as 175 in decimal is 10101111 in binary. All host bits are ones. This is the local broadcast address and cannot be used as a host address. F is incorrect, as 208 in decimal is 11010000 in binary. This is not a valid host address in this network, and all its host bits are zero.
A9: Answer: C. The network address would be 201.100.5.64 with a subnet mask of 255.255.255.240. A is incorrect, as it is the network address of subnet zero. B is incorrect, as it is the network address of another subnetwork. D is incorrect, as it is a valid host address on the 201.100.5.64 subnetwork. E is incorrect, as it is a broadcast address on another subnetwork. F is incorrect, as it is a valid host address on another subnetwork.
A10: Answer: A. TCP (Transmission Control Protocol) utilizes a three-way handshake to establish a session. B is incorrect, as IP (Internet Protocol) is used at Layer 3 of the OSI Model to provide logical addressing. C is incorrect, as UDP is not reliable and does not use a three-way handshake to establish a connection. D is incorrect, as IPX is not reliable and does not use a handshake method to provide a connection. E is incorrect, as frame relay does not provide any acknowledgment or error correction.
A11: Answer: A. TCP provides reliable, connection-oriented sessions to ensure that data is transferred correctly. B is incorrect, as IP (Internet Protocol) is used at Layer 3 of the OSI Model to provide logical addressing. C is incorrect, as IPX is not reliable and does not use a handshake method to provide a connection. D is incorrect, as frame relay does not provide any acknowledgment or error correction, and thus is unreliable and connectionless.
A12: Answer: C. UDP (User Datagram Protocol) relies on Layer 7 (Application) to handle error detection, correction, and control. Because of the low overhead, it is a very fast protocol. A is incorrect, as TCP contains significant overhead to handle the reliable delivery of data. B is incorrect, as IP (Internet Protocol) is used at Layer 3 of the OSI Model to provide logical addressing. D is incorrect, as SPX, Novell's proprietary connection-based protocol, provides reliable delivery and thus more latency. E is incorrect, as AppleTalk is a Layer 3 protocol that deals with logical addressing.
A13: Answer: B. Applications and operating systems have the capability to adjust the window size of TCP. The window size is the amount of data that can be sent before TCP requires an acknowledgment, or ACK. A is incorrect because adjusting the Maximum Transmission Unit merely adjusts how big the packets are or how much data they can contain. C is incorrect, as it does not exist in the TCP/IP protocol stack. D is incorrect, as the Frame Check Sequence (FCS) is used at the Data-link layer of the OSI Model to check for corrupted frames.
A14: Answer: B. When a host receiving information misses a segment from the TCP window, it sends an ACK message that shows the next segment number it is ready to receive. If this segment number is the same as a segment that was sent, the sending host knows to resend the information. A is incorrect, as the TCP segment number is included in the ACK sent. C and D are not valid acknowledgments and are thus incorrect.
A15: Answer: C. A Class C network can support 254 hosts. A is incorrect, as a Class A network supports more than 16 million hosts. B is incorrect, as a Class B network supports more than 65 thousand hosts. D is incorrect, as a Class D network is for use by multicast applications. E is incorrect, as Class E addresses are experimental and used only by the government and research organizations.
A16: Answers: A, C, and D. These addresses are all part of the private ranges of 10.x.x.x and 172.16.x.x–172.31.x.x. B is incorrect, as it does not fall into any of the RFC 1918-specified private ranges. Instead, it is a public IP address that is routable on the Internet. E is incorrect, as it is not a part of the private IP address range. It falls outside the 192.168.x.x range and thus is a public IP address.
A17: Answer: C. The subnet mask 255.255.255.224 gives you six usable subnetworks, assuming you are not using ip subnet-zero, with up to 30 available hosts per subnet. This subnet mask meets the criteria you have been given and even allows a bit of future growth. A is incorrect, as it is the default Class C subnet mask. It provides one network with 254 hosts. B is incorrect, as it gives only two subnetworks, assuming you are not using ip subnet-zero. D is incorrect, as it gives enough subnetworks but not enough hosts for the Customer Support or Engineering departments. E is incorrect, as it gives enough subnetworks but not enough hosts for most of the departments.
A18: Answer: A. User Datagram Protocol (UDP) relies on the applications to provide error correction or detection. B is incorrect, as TCP is reliable and provides connection-oriented sessions. C is incorrect, as SNMP is a management protocol used by devices to communicate information to a management system such as CiscoWorks or HP's OpenView. D is incorrect, as ICMP is used by such troubleshooting utilities as ping and traceroute.
A19: Answers: B and C. TCP numbers the sequence of the segments sent out to ensure that all data arrives safely. The receiving side must send back acknowledgments that all segments were received. If it sends back negative acknowledgments, TCP resends the data. A is incorrect, as Address Resolution Protocol (ARP) or Inverse ARP provide MAC address resolution. D is incorrect, as ping is a utility that checks TCP/IP connectivity. E is incorrect, as routing updates are used by routing protocols such as RIP or OSPF to update information stored on another router's routing table.
A20: Answer: A. By using windowing, you can increase the amount of data sent before an ACK is sent back by the receiving side. This increases throughput. B is incorrect, as increasing window size increases, not decreases, throughput. C is incorrect, as increasing window size decreases latency. D is incorrect, as the protocol still requires an ACK to be sent by the receiving side. This does not decrease reliability in the slightest.
A21: Answer: F. The 255.255.255.248 subnet mask used on a Class C IP network produces 30 usable subnets. A is incorrect; it does not create any subnets, as it is the default Class C subnet mask. B is incorrect, as it creates only 2 subnets—that is, if the IOS recognizes IP subnet zero. C is incorrect, as 255.255.255.192 creates only 2 usable subnets. D is incorrect, as 255.255.255.224 creates only 6 usable subnets. E is incorrect, as 255.255.255.240 creates only 14 usable subnets.
A22: Answer: A. Address Resolution Protocol (ARP) resolves IP addresses to MAC addresses. B is incorrect, as Reverse Address Resolution Protocol (RARP) resolves MAC addresses to IP addresses, thus the "reverse." C is incorrect, as Serial Line Address Resolution Protocol (SLARP) automatically assigns IP addresses to serial interfaces if AutoInstall is being used and HDLC is the protocol in use on that interface. D is incorrect, as DHCP automatically assigns IP addresses to interfaces.
A23: Answer: D. The IP address of a Layer 2 switch is strictly for management purposes and doesn't affect Layer 3 connectivity. A, B, and C are incorrect, as they are valid reasons why a user cannot ping a remote host. E is incorrect because a remote host is in a different subnet by definition.
A24: Answer: D. According to the IETF, the Class D IP address range is used for multicast group addresses. A is incorrect, as Class A addresses are used by large corporations and governments for unicast purposes. B is incorrect, as Class B addresses are used by large-to-medium corporations and service providers for unicast purposes. C is incorrect, as service providers, users, and small businesses use Class C addresses for unicast purposes. Unicast is based on one-to-one communication, whereas multicast is used for one-to-many communication.
A25: Answer: D. Prefix notation, or / notation, shows the number of subnet mask bits that are turned to one, signifying a network portion of the address. A is incorrect, as it does not show the number of hosts on a subnetwork. B is incorrect, as it does not show the number of subnetworks in use. C is incorrect because, even though you can figure out whether it is a Class A, B, or C address based on the prefixes of /8, /16, or /24, it does not necessarily show the class of the address.
A26: Answer: D. The custom subnet mask of 255.255.255.224 gives you 30 hosts. Even though this number exceeds the requested 16, if you borrow an additional bit, you have only 14 available hosts. A, B, and C do not give you any subnets at all, and thus are incorrect. E is incorrect, as it gives you only 14 available hosts.
A27: Answer: A. Class A networks have all been assigned to governments and extremely large corporations. B is incorrect, as small-to-medium size companies would receive only a Class C network. C and D are incorrect, as a small office/home office (SOHO) or individual would not receive a network—only a few IP addresses from a Class C network.
A28: Answers: B and D. The address 192.168.5.98/27 has a decimal subnet mask of 255.255.255.224 and uses an increment of 32. This ends up making the network range 192.168.5.96–192.168.5.127. Answer A is incorrect because this is the broadcast address of the previous subnet. Answer C is incorrect because it is the network address of the following subnet.
A29: Answer: D. The IP address 172.31.45.34 is part of the RFC 1918-defined private IP address range for a Class B network. A, B, C, and E are incorrect, as they are all public IP addresses that can be routed on the Internet.
A30: Answer: B. The default Class B subnet mask is 255.255.0.0, or /16 in prefix notation. A is incorrect, as it shows a broadcast. C is incorrect, as it is a custom subnet mask, more than likely used for a Class A network. D is incorrect, as it is a special mask typically used for default routes.
A31: Answer: C. It is not a valid host address; 192.168.5.95/27 is a directed broadcast address for the 192.168.5.64 network. A is incorrect, as you can certainly assign Class C addresses to any type of interface. B is incorrect, as the /27 mask is the 255.255.255.224 subnet mask, which is perfectly valid. D is incorrect because it is a private IP address. E is incorrect, as the fact that it is a private IP address will not cause it to be refused by an interface.
A32: Answer: B. This gives you 126 subnets, assuming you are not using ip subnet-zero, with 510 hosts per subnet. A is incorrect, as it does not provide you with enough hosts to meet the criteria. C is incorrect, as it is an invalid subnet mask. Subnet masks must have contiguous ones. D is incorrect, as it is the default Class B subnet mask, and as such, you would not have any subnets.
A33: Answer: B. The address 192.168.2.37 is a valid host address on the 192.168.2.32 network, which has a directed broadcast address of 192.168.2.39. A, C, and D are incorrect, as 192.168.2.37 does not fall on any of those subnetworks with the given subnet mask.
A34: Answer: A. The number 11011010 = 218 in decimal. B is incorrect, as 11011011 = 219. C is incorrect, as 11011100 = 220. D is incorrect, as 11011101 = 221.
A35: Answer: C. The number 01011010 = 90 in decimal. A is incorrect, as 01001011 = 75. B is incorrect, as 01010011 = 83. D is incorrect, as 01100001 = 97.
A36: Answer: B. The number 11010110 = 214 in decimal. A is incorrect, as 11000110 = 198. C is incorrect, as 11111100 = 252. D is incorrect, as 11111111 = 255.
A37: Answer: A. The number 10110110 = 182 in decimal. B is incorrect, as 11000000 = 192. C is incorrect, as 11001010 = 202. D is incorrect, as 11010100 = 212.
A38: Answers: B, C, and D. They are valid host addresses when using a 255.255.255.224 subnet mask against the address. A is incorrect, as it is a broadcast address on the 16.234.118.32 network. E is incorrect, as it is a broadcast address on the 210.45.116.128 network. F is incorrect, as it is the network address for 237.63.12.192.
A39: Answer: E. The 255.255.255.248, or /28 subnet mask, gives you 16 subnetworks and 14 usable hosts, using the 2^n formula for subnets and (2^n – 2) formula for usable hosts, where n equals the number of bits borrowed for the subnet, or number of bits left for the hosts. You are able to use the first and last subnetworks because of the ip subnet-zero command on your router. A is incorrect, as it would be a /30 mask. B is incorrect, as it would be a /27 mask. C is incorrect, as there would never be 32 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork. D is incorrect, as you would never have 16 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork.
A40: Answer: A. TCP adds overhead with acknowledgments and session handshakes. B is incorrect, as TCP tags with sequence numbers. C is incorrect, as TCP is reliable and ensures data delivery. D is incorrect, as TCP has built-in mechanisms to handle sequencing and delivery and does not require the application's assistance.
A41: Answer: A. The mask /30 gives you 62 subnetworks and two available hosts per subnet using the (2^n [ms] 2) formula, where n equals the number of bits borrowed for the subnet, or number of bits left for the hosts. Because the router is not using ip subnet-zero, you cannot use the first or last subnet, which is why you subtract 2 from both the subnetworks and hosts. B is incorrect, as that would be a /27 mask. C is incorrect, as there would never be 32 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork. D is incorrect, as you would never have 16 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork. E is incorrect, as the /28 subnet mask gives you 14 subnetworks and 14 possible hosts.
A42: Answers: A and B. They are considered network ID addresses. They have all zeros in the host portion of the IP address with the subnet mask given. C, D, and E are incorrect, as they are all directed Broadcast Addresses on subnets.
A43: Answers: A, C, and D. A subnet mask of 255.255.255.240 divides the fourth octet into subnet parts: the highest four bits and a host port (the lowest four bits). You simply check the fourth octet to ensure that all subnet and host parts are okay. The host bit portion cannot be 0000 or 1111. A, C, and D are correct because 33 in decimal is 00100001, 119 in decimal is 01110111, and 126 in decimal is 1111110. B is incorrect, as 112 in decimal is 1110000 in binary, which is not a valid host address in this network—all host bits are zero. E is incorrect, as 175 in decimal is 10101111 in binary—all host bits are ones. This is the local broadcast address and cannot be used as a host address. F is incorrect, as 208 in decimal is 11010000 in binary. This is not a valid host address in this network, as it has all host bits of zero.
A44: Answer: E. The fourth byte in the IP address is 159, the binary value of which is 1011111. So, this is the broadcast address for 198.57.78.0/27 network. A is incorrect, as the binary value for 33 is 00100001. B is incorrect, as the binary value for 64 is 01000000. C and D are incorrect, as the binary value for 97 is 01100001. F is incorrect, as the binary value for 254 is 11111110. These are not broadcast addresses for the 198.57.78.0/27 network.
A45: Answer: C. If you use the subnet mask prefix value /28, 4 bits are left for the host portion. The total number of hosts is 16 (2 are reserved for network and broadcast in each subnetwork). The 165.100.5.68 host resides in subnetwork 165.100.5.64. Valid hosts in this network are 165.100.5.65–165.100.5.79. A is incorrect, as it is the network address for the first subnet, also known as subnet 0. B is incorrect, as it is the network address for 165.100.5.32. Valid hosts are 165.100.5.33–165.100.5.46. D is incorrect, as it is one of the valid hosts in subnetwork 165.100.5.64. E is incorrect, as it is the broadcast address. F is incorrect, as it is a valid host in subnetwork 165.100.5.0.
A46: Answer: C. TCP stands for Transmission Control Protocol. A, B, and D are incorrect, as they are nonexisting protocols.
A47: Answer: D. UDP stands for User Datagram Protocol. It is part of the TCP/IP protocol suite and operates at Layer 4 of the OSI Model. A, B, and C name nonexistent protocols or programs.
A48: Answer: D. UDP relies on applications to provide error correction and reliability of transmission. A is incorrect, as it describes Remote Copy Protocol (RCP). B is incorrect, as it describes Simple Mail Transfer Protocol (SMTP). C is incorrect, as it describes File Transfer Protocol (FTP).
A49: Answers: C, E, and F. These addresses are not private addresses defined by RFC 1918. These addresses can be routed across the public Internet. A is incorrect, as it is part of the private range of 10.x.x.x. B is incorrect, as it is part of the private range of 172.16.x.x–172.16.31.x.x. D is incorrect, as it is part of the private range of 192.168.x.x.
A50: Answers: A and C. A is correct because you must have a public IP address assigned to your interface to be able to communicate across the Internet. C is correct, as you must turn on the interface by using the no shutdown command. B is incorrect, as you must turn on the interface, not disable it with the shutdown command. D is incorrect, as duplex settings are not valid on serial interfaces, only on Ethernet interfaces.
A1: Answer: D. The default subnet mask for Class C is 255.255.255.0. A is incorrect, as it is the default mask for Class A. B is incorrect, as it is the default mask for Class B. C is incorrect, as this is not a valid mask. Subnet masks must be consecutive ones. E is not correct, as it is the subnet mask of all ones.
A2: Answer: A. Transmission Control Protocol (TCP) provides reliable end-to-end connectivity, along with error-detection capabilities. B is incorrect, as UDP does not provide any reliability. C is incorrect, as IP does not provide reliability. D is incorrect, as ICMP is used to help troubleshoot TCP/IP connections.
A3: Answer: C. This particular subnet mask allows for up to 62 hosts per network. A is incorrect, as it allows for 65,534 hosts. B is incorrect, as it allows up to 254 hosts. D is incorrect, as it is not a valid subnet mask.
A4: Answer: D. The next valid IP host address in the 172.16.12.32 network is 172.16.12.34. A is incorrect, as it is on a different subnetwork with a /28 mask. B is incorrect, as it is the network address for that particular subnetwork. C is incorrect, as it is the same IP address as the router interface. E and F are incorrect as well, as they are on different subnets than the router interface. Choice G is incorrect because it represents the broadcast address for the 172.16.12.32 subnetwork and cannot be used as a host address.
A5: Answer: C. The network address for the IP address is 172.16.208.0–255.255.240.0. A, B, and D are incorrect, as they are different subnetworks.
A6: Answer: D. This subnet mask gives you two additional subnets using VLSM, with up to 14 hosts per subnetwork. A is incorrect, as it is a higher subnet mask than your original /26, which is actually called supernetting. B is incorrect because it is your original subnet mask. C is incorrect, as it does not give you enough subnets. E is incorrect, as it gives you enough subnets (six), but you would have only six hosts.
A7: Answer: A. You have actually not done any subnetting with a /24 mask; it is the default Class C subnet mask of 255.255.255.0. This gives you one network with 254 possible hosts. B, C, and D are incorrect because you have not borrowed any bits to create subnetworks.
A8: Answers: A, C, and D. A subnet mask of 255.255.255.240 divides the fourth octet into subnet parts: the highest four bits and a host port (the lowest four bits). You simply check the fourth octet to ensure that all subnet and host parts are okay. The host bit portion cannot be 0000 or 1111. A, C, and D are correct because 33 in decimal is 00100001, 119 in decimal is 01110111, and 126 in decimal is 1111110. B is incorrect, as 112 in decimal is 1110000 in binary. This is not a valid host address in this network. All its host bits are zero. E is incorrect, as 175 in decimal is 10101111 in binary. All host bits are ones. This is the local broadcast address and cannot be used as a host address. F is incorrect, as 208 in decimal is 11010000 in binary. This is not a valid host address in this network, and all its host bits are zero.
A9: Answer: C. The network address would be 201.100.5.64 with a subnet mask of 255.255.255.240. A is incorrect, as it is the network address of subnet zero. B is incorrect, as it is the network address of another subnetwork. D is incorrect, as it is a valid host address on the 201.100.5.64 subnetwork. E is incorrect, as it is a broadcast address on another subnetwork. F is incorrect, as it is a valid host address on another subnetwork.
A10: Answer: A. TCP (Transmission Control Protocol) utilizes a three-way handshake to establish a session. B is incorrect, as IP (Internet Protocol) is used at Layer 3 of the OSI Model to provide logical addressing. C is incorrect, as UDP is not reliable and does not use a three-way handshake to establish a connection. D is incorrect, as IPX is not reliable and does not use a handshake method to provide a connection. E is incorrect, as frame relay does not provide any acknowledgment or error correction.
A11: Answer: A. TCP provides reliable, connection-oriented sessions to ensure that data is transferred correctly. B is incorrect, as IP (Internet Protocol) is used at Layer 3 of the OSI Model to provide logical addressing. C is incorrect, as IPX is not reliable and does not use a handshake method to provide a connection. D is incorrect, as frame relay does not provide any acknowledgment or error correction, and thus is unreliable and connectionless.
A12: Answer: C. UDP (User Datagram Protocol) relies on Layer 7 (Application) to handle error detection, correction, and control. Because of the low overhead, it is a very fast protocol. A is incorrect, as TCP contains significant overhead to handle the reliable delivery of data. B is incorrect, as IP (Internet Protocol) is used at Layer 3 of the OSI Model to provide logical addressing. D is incorrect, as SPX, Novell's proprietary connection-based protocol, provides reliable delivery and thus more latency. E is incorrect, as AppleTalk is a Layer 3 protocol that deals with logical addressing.
A13: Answer: B. Applications and operating systems have the capability to adjust the window size of TCP. The window size is the amount of data that can be sent before TCP requires an acknowledgment, or ACK. A is incorrect because adjusting the Maximum Transmission Unit merely adjusts how big the packets are or how much data they can contain. C is incorrect, as it does not exist in the TCP/IP protocol stack. D is incorrect, as the Frame Check Sequence (FCS) is used at the Data-link layer of the OSI Model to check for corrupted frames.
A14: Answer: B. When a host receiving information misses a segment from the TCP window, it sends an ACK message that shows the next segment number it is ready to receive. If this segment number is the same as a segment that was sent, the sending host knows to resend the information. A is incorrect, as the TCP segment number is included in the ACK sent. C and D are not valid acknowledgments and are thus incorrect.
A15: Answer: C. A Class C network can support 254 hosts. A is incorrect, as a Class A network supports more than 16 million hosts. B is incorrect, as a Class B network supports more than 65 thousand hosts. D is incorrect, as a Class D network is for use by multicast applications. E is incorrect, as Class E addresses are experimental and used only by the government and research organizations.
A16: Answers: A, C, and D. These addresses are all part of the private ranges of 10.x.x.x and 172.16.x.x–172.31.x.x. B is incorrect, as it does not fall into any of the RFC 1918-specified private ranges. Instead, it is a public IP address that is routable on the Internet. E is incorrect, as it is not a part of the private IP address range. It falls outside the 192.168.x.x range and thus is a public IP address.
A17: Answer: C. The subnet mask 255.255.255.224 gives you six usable subnetworks, assuming you are not using ip subnet-zero, with up to 30 available hosts per subnet. This subnet mask meets the criteria you have been given and even allows a bit of future growth. A is incorrect, as it is the default Class C subnet mask. It provides one network with 254 hosts. B is incorrect, as it gives only two subnetworks, assuming you are not using ip subnet-zero. D is incorrect, as it gives enough subnetworks but not enough hosts for the Customer Support or Engineering departments. E is incorrect, as it gives enough subnetworks but not enough hosts for most of the departments.
A18: Answer: A. User Datagram Protocol (UDP) relies on the applications to provide error correction or detection. B is incorrect, as TCP is reliable and provides connection-oriented sessions. C is incorrect, as SNMP is a management protocol used by devices to communicate information to a management system such as CiscoWorks or HP's OpenView. D is incorrect, as ICMP is used by such troubleshooting utilities as ping and traceroute.
A19: Answers: B and C. TCP numbers the sequence of the segments sent out to ensure that all data arrives safely. The receiving side must send back acknowledgments that all segments were received. If it sends back negative acknowledgments, TCP resends the data. A is incorrect, as Address Resolution Protocol (ARP) or Inverse ARP provide MAC address resolution. D is incorrect, as ping is a utility that checks TCP/IP connectivity. E is incorrect, as routing updates are used by routing protocols such as RIP or OSPF to update information stored on another router's routing table.
A20: Answer: A. By using windowing, you can increase the amount of data sent before an ACK is sent back by the receiving side. This increases throughput. B is incorrect, as increasing window size increases, not decreases, throughput. C is incorrect, as increasing window size decreases latency. D is incorrect, as the protocol still requires an ACK to be sent by the receiving side. This does not decrease reliability in the slightest.
A21: Answer: F. The 255.255.255.248 subnet mask used on a Class C IP network produces 30 usable subnets. A is incorrect; it does not create any subnets, as it is the default Class C subnet mask. B is incorrect, as it creates only 2 subnets—that is, if the IOS recognizes IP subnet zero. C is incorrect, as 255.255.255.192 creates only 2 usable subnets. D is incorrect, as 255.255.255.224 creates only 6 usable subnets. E is incorrect, as 255.255.255.240 creates only 14 usable subnets.
A22: Answer: A. Address Resolution Protocol (ARP) resolves IP addresses to MAC addresses. B is incorrect, as Reverse Address Resolution Protocol (RARP) resolves MAC addresses to IP addresses, thus the "reverse." C is incorrect, as Serial Line Address Resolution Protocol (SLARP) automatically assigns IP addresses to serial interfaces if AutoInstall is being used and HDLC is the protocol in use on that interface. D is incorrect, as DHCP automatically assigns IP addresses to interfaces.
A23: Answer: D. The IP address of a Layer 2 switch is strictly for management purposes and doesn't affect Layer 3 connectivity. A, B, and C are incorrect, as they are valid reasons why a user cannot ping a remote host. E is incorrect because a remote host is in a different subnet by definition.
A24: Answer: D. According to the IETF, the Class D IP address range is used for multicast group addresses. A is incorrect, as Class A addresses are used by large corporations and governments for unicast purposes. B is incorrect, as Class B addresses are used by large-to-medium corporations and service providers for unicast purposes. C is incorrect, as service providers, users, and small businesses use Class C addresses for unicast purposes. Unicast is based on one-to-one communication, whereas multicast is used for one-to-many communication.
A25: Answer: D. Prefix notation, or / notation, shows the number of subnet mask bits that are turned to one, signifying a network portion of the address. A is incorrect, as it does not show the number of hosts on a subnetwork. B is incorrect, as it does not show the number of subnetworks in use. C is incorrect because, even though you can figure out whether it is a Class A, B, or C address based on the prefixes of /8, /16, or /24, it does not necessarily show the class of the address.
A26: Answer: D. The custom subnet mask of 255.255.255.224 gives you 30 hosts. Even though this number exceeds the requested 16, if you borrow an additional bit, you have only 14 available hosts. A, B, and C do not give you any subnets at all, and thus are incorrect. E is incorrect, as it gives you only 14 available hosts.
A27: Answer: A. Class A networks have all been assigned to governments and extremely large corporations. B is incorrect, as small-to-medium size companies would receive only a Class C network. C and D are incorrect, as a small office/home office (SOHO) or individual would not receive a network—only a few IP addresses from a Class C network.
A28: Answers: B and D. The address 192.168.5.98/27 has a decimal subnet mask of 255.255.255.224 and uses an increment of 32. This ends up making the network range 192.168.5.96–192.168.5.127. Answer A is incorrect because this is the broadcast address of the previous subnet. Answer C is incorrect because it is the network address of the following subnet.
A29: Answer: D. The IP address 172.31.45.34 is part of the RFC 1918-defined private IP address range for a Class B network. A, B, C, and E are incorrect, as they are all public IP addresses that can be routed on the Internet.
A30: Answer: B. The default Class B subnet mask is 255.255.0.0, or /16 in prefix notation. A is incorrect, as it shows a broadcast. C is incorrect, as it is a custom subnet mask, more than likely used for a Class A network. D is incorrect, as it is a special mask typically used for default routes.
A31: Answer: C. It is not a valid host address; 192.168.5.95/27 is a directed broadcast address for the 192.168.5.64 network. A is incorrect, as you can certainly assign Class C addresses to any type of interface. B is incorrect, as the /27 mask is the 255.255.255.224 subnet mask, which is perfectly valid. D is incorrect because it is a private IP address. E is incorrect, as the fact that it is a private IP address will not cause it to be refused by an interface.
A32: Answer: B. This gives you 126 subnets, assuming you are not using ip subnet-zero, with 510 hosts per subnet. A is incorrect, as it does not provide you with enough hosts to meet the criteria. C is incorrect, as it is an invalid subnet mask. Subnet masks must have contiguous ones. D is incorrect, as it is the default Class B subnet mask, and as such, you would not have any subnets.
A33: Answer: B. The address 192.168.2.37 is a valid host address on the 192.168.2.32 network, which has a directed broadcast address of 192.168.2.39. A, C, and D are incorrect, as 192.168.2.37 does not fall on any of those subnetworks with the given subnet mask.
A34: Answer: A. The number 11011010 = 218 in decimal. B is incorrect, as 11011011 = 219. C is incorrect, as 11011100 = 220. D is incorrect, as 11011101 = 221.
A35: Answer: C. The number 01011010 = 90 in decimal. A is incorrect, as 01001011 = 75. B is incorrect, as 01010011 = 83. D is incorrect, as 01100001 = 97.
A36: Answer: B. The number 11010110 = 214 in decimal. A is incorrect, as 11000110 = 198. C is incorrect, as 11111100 = 252. D is incorrect, as 11111111 = 255.
A37: Answer: A. The number 10110110 = 182 in decimal. B is incorrect, as 11000000 = 192. C is incorrect, as 11001010 = 202. D is incorrect, as 11010100 = 212.
A38: Answers: B, C, and D. They are valid host addresses when using a 255.255.255.224 subnet mask against the address. A is incorrect, as it is a broadcast address on the 16.234.118.32 network. E is incorrect, as it is a broadcast address on the 210.45.116.128 network. F is incorrect, as it is the network address for 237.63.12.192.
A39: Answer: E. The 255.255.255.248, or /28 subnet mask, gives you 16 subnetworks and 14 usable hosts, using the 2^n formula for subnets and (2^n – 2) formula for usable hosts, where n equals the number of bits borrowed for the subnet, or number of bits left for the hosts. You are able to use the first and last subnetworks because of the ip subnet-zero command on your router. A is incorrect, as it would be a /30 mask. B is incorrect, as it would be a /27 mask. C is incorrect, as there would never be 32 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork. D is incorrect, as you would never have 16 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork.
A40: Answer: A. TCP adds overhead with acknowledgments and session handshakes. B is incorrect, as TCP tags with sequence numbers. C is incorrect, as TCP is reliable and ensures data delivery. D is incorrect, as TCP has built-in mechanisms to handle sequencing and delivery and does not require the application's assistance.
A41: Answer: A. The mask /30 gives you 62 subnetworks and two available hosts per subnet using the (2^n [ms] 2) formula, where n equals the number of bits borrowed for the subnet, or number of bits left for the hosts. Because the router is not using ip subnet-zero, you cannot use the first or last subnet, which is why you subtract 2 from both the subnetworks and hosts. B is incorrect, as that would be a /27 mask. C is incorrect, as there would never be 32 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork. D is incorrect, as you would never have 16 hosts per subnet; you always have to subtract 2 from the 2^n formula because of the network ID and the directed broadcast address on each subnetwork. E is incorrect, as the /28 subnet mask gives you 14 subnetworks and 14 possible hosts.
A42: Answers: A and B. They are considered network ID addresses. They have all zeros in the host portion of the IP address with the subnet mask given. C, D, and E are incorrect, as they are all directed Broadcast Addresses on subnets.
A43: Answers: A, C, and D. A subnet mask of 255.255.255.240 divides the fourth octet into subnet parts: the highest four bits and a host port (the lowest four bits). You simply check the fourth octet to ensure that all subnet and host parts are okay. The host bit portion cannot be 0000 or 1111. A, C, and D are correct because 33 in decimal is 00100001, 119 in decimal is 01110111, and 126 in decimal is 1111110. B is incorrect, as 112 in decimal is 1110000 in binary, which is not a valid host address in this network—all host bits are zero. E is incorrect, as 175 in decimal is 10101111 in binary—all host bits are ones. This is the local broadcast address and cannot be used as a host address. F is incorrect, as 208 in decimal is 11010000 in binary. This is not a valid host address in this network, as it has all host bits of zero.
A44: Answer: E. The fourth byte in the IP address is 159, the binary value of which is 1011111. So, this is the broadcast address for 198.57.78.0/27 network. A is incorrect, as the binary value for 33 is 00100001. B is incorrect, as the binary value for 64 is 01000000. C and D are incorrect, as the binary value for 97 is 01100001. F is incorrect, as the binary value for 254 is 11111110. These are not broadcast addresses for the 198.57.78.0/27 network.
A45: Answer: C. If you use the subnet mask prefix value /28, 4 bits are left for the host portion. The total number of hosts is 16 (2 are reserved for network and broadcast in each subnetwork). The 165.100.5.68 host resides in subnetwork 165.100.5.64. Valid hosts in this network are 165.100.5.65–165.100.5.79. A is incorrect, as it is the network address for the first subnet, also known as subnet 0. B is incorrect, as it is the network address for 165.100.5.32. Valid hosts are 165.100.5.33–165.100.5.46. D is incorrect, as it is one of the valid hosts in subnetwork 165.100.5.64. E is incorrect, as it is the broadcast address. F is incorrect, as it is a valid host in subnetwork 165.100.5.0.
A46: Answer: C. TCP stands for Transmission Control Protocol. A, B, and D are incorrect, as they are nonexisting protocols.
A47: Answer: D. UDP stands for User Datagram Protocol. It is part of the TCP/IP protocol suite and operates at Layer 4 of the OSI Model. A, B, and C name nonexistent protocols or programs.
A48: Answer: D. UDP relies on applications to provide error correction and reliability of transmission. A is incorrect, as it describes Remote Copy Protocol (RCP). B is incorrect, as it describes Simple Mail Transfer Protocol (SMTP). C is incorrect, as it describes File Transfer Protocol (FTP).
A49: Answers: C, E, and F. These addresses are not private addresses defined by RFC 1918. These addresses can be routed across the public Internet. A is incorrect, as it is part of the private range of 10.x.x.x. B is incorrect, as it is part of the private range of 172.16.x.x–172.16.31.x.x. D is incorrect, as it is part of the private range of 192.168.x.x.
A50: Answers: A and C. A is correct because you must have a public IP address assigned to your interface to be able to communicate across the Internet. C is correct, as you must turn on the interface by using the no shutdown command. B is incorrect, as you must turn on the interface, not disable it with the shutdown command. D is incorrect, as duplex settings are not valid on serial interfaces, only on Ethernet interfaces.
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