Network Integration Midterm Exam - Quiz Questions

Which of the following are private IP networks? (Select two answers.) a. 172.31.0.0 b. 172.32.0.0 c. 192.168.255.0 d. 192.1.168.0 e. 11.0.0.0

A (172.31.0.0) and C (192.168.255.0) . The private IPv4 networks, defined by RFC 1918, are Class A network 10.0.0.0, the 16 Class B networks from 172.16.0.0 to 172.31.0.0, and the 256 Class C networks that begin with 192.168.

Which of the following are public IP networks? (Select three answers.) a. 9.0.0.0 b. 172.30.0.0 c. 192.168.255.0 d. 192.1.168.0 e. 1.0.0.0

A (9.0.0.0) , D (192.1.168.0) , and E (1.0.0.0 ) . The private IPv4 networks, defined by RFC 1918, are Class A network 10.0.0.0, the 16 Class B networks from 172.16.0.0 to 172.31.0.0, and the 256 Class C networks that begin with 192.168. The three correct answers are from the public IP network range, and none are reserved values.

Which of the following protocols are examples of TCP/IP data link layer protocols? (Choose two answers.) a. Ethernet b. HTTP c. IP d. UDP e. SMTP f. TCP g. PPP

A (Ethernet) and G (PPP) . Of the remaining answers, IP is a network layer protocol, TCP and UDP are transport layer protocols, and SMTP and HTTP are application layer protocols.

Which of the following statements describes part of the process of how a switch decides to forward a frame destined for a known unicast MAC address? a. It compares the unicast destination address to the bridging, or MAC address, table. b. It compares the unicast source address to the bridging, or MAC address, table. c. It forwards the frame out all interfaces in the same VLAN except for the incoming interface. d. It compares the destination IP address to the destination MAC address. e. It compares the frame's incoming interface to the source MAC entry in the MAC address table.

A (It compares the unicast destination address to the bridging, or MAC address, table.) . A switch compares the destination address to the MAC address table. If a matching entry is found, the switch knows out which interface to forward the frame. If no matching entry is found, the switch floods the frame.

Which of the following statements best describes what a switch does with a frame destined for an unknown unicast address? a. It forwards out all interfaces in the same VLAN except for the incoming interface. b. It forwards the frame out the one interface identified by the matching entry in the MAC address table. c. It compares the destination IP address to the destination MAC address. d. It compares the frame's incoming interface to the source MAC entry in the MAC address table.

A (It forwards out all interfaces in the same VLAN except for the incoming interface.) . A switch floods broadcast frames, multicast frames (if no multicast optimizations are enabled), and unknown unicast destination frames (frames whose destination MAC address is not in the MAC address table).

Which OSI layer defines the standards for cabling and connectors? a. Layer 1 b. Layer 2 c. Layer 3 d. Layer 4 e. Layer 5, 6, or 7

A (Layer 1) . The OSI physical layer includes all standards that specify the shape of connectors, wiring in cabling, electrical details, and encoding that the electrical signals use to encode bits over a cable.

Working at the help desk, you receive a call and learn a user's PC IP address and mask (192.168.9.1/27). When thinking about this using classful logic, you determine the number of network (N), subnet (S), and host (H) bits. Which of the following is true in this case? a. N=24 b. S=24 c. H=8 d. H=7

A (N=24) . The size of the network part is always either 8, 16, or 24 bits, based on whether it is Class A, B, or C, respectively. As a Class C address, N=24. The number of subnet bits is the difference between the prefix length (27) and N, so S=3 in this case. The size of the host part is a number that, when added to the prefix length (27), gives you 32, so H=5 in this case.

Before Class B network 172.16.0.0 is subnetted by a network engineer, what parts of the structure of the IP addresses in this network already exist, with a specific size? (Select two answers.) a. Network b. Subnet c. Host d. Broadcast

A (Network) and C (Host) . An unsubnetted Class A, B, or C network has two parts: the network and host parts.

Which of the following devices would be in the same broadcast domain as PC1? (Choose three answers.) a. PC2, which is separated from PC1 by an Ethernet hub b. PC3, which is separated from PC1 by a transparent bridge c. PC4, which is separated from PC1 by an Ethernet switch d. PC5, which is separated from PC1 by a router

A (PC2, which is separated from PC1 by an Ethernet hub) , B (PC3, which is separated from PC1 by a transparent bridge) , and C (PC4, which is separated from PC1 by an Ethernet switch) . A broadcast domain contains all devices whose sent broadcast frames should be delivered to all the other devices in the domain. Hubs, repeaters, bridges, and switches do not separate or segment a LAN into multiple broadcast domains, whereas routers do.

Which of the following devices would be in the same collision domain as PC1? a. PC2, which is separated from PC1 by an Ethernet hub b. PC3, which is separated from PC1 by a transparent bridge c. PC4, which is separated from PC1 by an Ethernet switch d. PC5, which is separated from PC1 by a router

A (PC2, which is separated from PC1 by an Ethernet hub) . A collision domain contains all devices whose frames could collide with frames sent by all the other devices in the domain. Bridges, switches, and routers separate or segment a LAN into multiple collision domains, whereas hubs and repeaters do not.

Host A is a PC, connected to switch SW1 and assigned to VLAN 1. Which of the following are typically assigned an IP address in the same subnet as host A? (Select two answers) a. The local router's WAN interface b. The local router's LAN interface c. All other hosts attached to the same switch d. Other hosts attached to the same switch and also in VLAN 1

A (The local router's WAN interface) and D (Other hosts attached to the same switch and also in VLAN 1 ) . The general rule to determine whether two devices' interfaces should be in the same subnet is whether the two interfaces are separated from each other by a router. To provide a way for hosts in one VLAN to send data to hosts outside that VLAN, a local router must connect its LAN interface to the same VLAN as the hosts, and have an address in the same subnet as the hosts. All the hosts in that same VLAN on the same switch would not be separated from each other by a router, so these hosts would also be in the same subnet. However, another PC, connected to the same switch but in a different VLAN, will require its packets to flow through a router to reach Host A, so Host A's IP address would need to be in a different subnet compared to this new host.

Which of the following are true about IP address 192.168.6.7's IP network? (Select two answers.) a. The network ID is 192.168.6.0. b. The network is a Class B network. c. The default mask for the network is 255.255.255.0. d. The number of host bits in the unsubnetted network is 16.

A (The network ID is 192.168.6.0.) and C (The default mask for the network is 255.255.255.0.) . The first octet (192) is in the range of values for Class C addresses (192-223). As a result, the network ID can be formed by copying the first three octets (192.168.6) and writing 0 for the last octet (192.168.6.0). The default mask for all Class C networks is 255.255.255.0, and the number of host bits in all unsubnetted Class C networks is 8.

PC1, with MAC address 1111.1111.1111, is connected to Switch SW1's Fa0/1 interface. PC2, with MAC address 2222.2222.2222, is connected to SW1's Fa0/2 interface. PC3, with MAC address 3333.3333.3333, connects to SW1's Fa0/3 interface. The switch begins with no dynamically learned MAC addresses, followed by PC1 sending a frame with a destination address of 2222.2222.2222. If the next frame to reach the switch is a frame sent by PC3, destined for PC2's MAC address of 2222.2222.2222, which of the following are true? (Choose two answers.) a. The switch forwards the frame out interface Fa0/1. b. The switch forwards the frame out interface Fa0/2. c. The switch forwards the frame out interface Fa0/3. d. The switch discards (filters) the frame.

A (The switch forwards the frame out interface Fa0/1.) and B (The switch forwards the frame out interface Fa0/2.) . When the frame sent by PC3 arrives at the switch, the switch has learned a MAC address table entry for only 1111.1111.1111, PC1's MAC address. PC3's frame, addressed to 2222.2222.2222, is flooded, which means it is forwarded out all interfaces except for the interface on which the frame arrived.

The process of a web server adding a TCP header to the contents of a web page, followed by adding an IP header and then adding a data link header and trailer is an example of what? a. Data encapsulation b. Same-layer interaction c. OSI model d. All of these answers are correct.

A. (Data encapsulation). Encapsulation is defined as the process of adding a header in front of data supplied by a higher layer (and possibly adding a trailer as well).

Which of the following answers lists the prefix (CIDR) format equivalent of 255.255.255.240? a. /26 b. /28 c. /27 d. /30 e. /29

B (/28). Thinking about the conversion one octet at a time, the first three octets each convert to 8 binary 1s. 240 converts to 8-bit binary 11110000, so the total number of binary 1s (which defines the prefix length) is 8+8+8+4 = /28.

Which of the following are not valid Class A network IDs? (Choose two answers.) a. 1.0.0.0 b. 130.0.0.0 c. 127.0.0.0 d. 9.0.0.0

B (130.0.0.0) and C (127.0.0.0) . Class A networks have a first octet in the range of 1-126, inclusive, and their network IDs have a 0 in the last three octets. 130.0.0.0 is actually a Class B network (first octet range 128-191, inclusive). All addresses that begin with 127 are reserved, so 127.0.0.0 is not a Class A network.

Which of the following answers lists the dotted-decimal notation (DDN) equivalent of /30? a. 255.255.255.192 b. 255.255.255.252 c. 255.255.255.240 d. 255.255.254.0 e. 255.255.255.0

B (255.255.255.252) . /30 is the equivalent of the mask that in binary has 30 binary 1s. To convert that to DDN format, write down all the binary 1s (30 in this case), followed by binary 0s for the remainder of the 32-bit mask. Then take 8 bits at a time, and convert from binary to decimal (or memorize the nine possible DDN mask octet values and their binary equivalents). Using the /30 mask in this question, the binary mask is 11111111 11111111 11111111 11111100. Each of the first three octets is all binary 1, so each converts to 255. The last octet, 11111100, converts to 252, for a DDN mask of 255.255.255.252. See Appendix A for a decimal/binary conversion table.

The process of HTTP asking TCP to send some data and making sure that it is received correctly is an example of what? a. Same-layer interaction b. Adjacent-layer interaction c. OSI model d. All of these answers are correct.

B (Adjacent-layer interaction) . Adjacent-layer interaction occurs on one computer, with two adjacent layers in the model. The higher layer requests services from the next lower layer, and the lower layer provides the services to the next higher layer.

In a LAN, which of the following terms best equates to the term VLAN? a. Collision domain b. Broadcast domain c. Subnet d. Single switch e. Trunk

B (Broadcast domain) . A VLAN is a set of devices in the same Layer 2 broadcast domain. A subnet often includes the exact same set of devices, but it is a Layer 3 concept. A collision domain refers to a set of Ethernet devices, but with different rules than VLAN rules for determining which devices are in the same collision domain.

Which of the following comparisons does a switch make when deciding whether a new MAC address should be added to its MAC address table? a. It compares the unicast destination address to the bridging, or MAC address, table. b. It compares the unicast source address to the bridging, or MAC address, table. c. It compares the VLAN ID to the bridging, or MAC address, table. d. It compares the destination IP address's ARP cache entry to the bridging, or MAC address, table.

B (It compares the unicast source address to the bridging, or MAC address, table.) . Switches need to learn the location of each MAC address used in the LAN relative to that local switch. When a switch sends a frame, the source MAC identifies the sender. The interface in which the frame arrives identifies the local switch interface closest to that node in the LAN topology.

A Class B network needs to be subnetted such that it supports 100 subnets and 100 hosts/subnet. Which of the following answers list a workable combination for the number of network, subnet, and host bits? (Select two answers.) a. Network = 16, subnet = 7, host = 7 b. Network = 16, subnet = 8, host = 8 c. Network = 16, subnet = 9, host = 7 d. Network = 8, subnet = 7, host = 17

B (Network = 16, subnet = 8, host = 8) and C (Network = 16, subnet = 9, host = 7). At least 7 subnet bits are needed, because 26 = 64, so 6 subnet bits could not number 100 different subnets. Seven subnet bits could, because 27 = 128 => 100. Similarly, 6 host bits is not enough, because 26 - 2 = 62, but 7 host bits is enough, because 27 - 2 = 126 => 100. The number of network, subnet, and host bits must total 32 bits, making one of the answers incorrect. The answer with 8 network bits cannot be correct because the question states that a Class B network is used, so the number of network bits must always be 16. The two correct answers have 16 network bits (required because the question states the use of a Class B network), and at least 7 subnet and host bits each.

The process of TCP on one computer marking a TCP segment as segment 1, and the receiving computer then acknowledging the receipt of TCP segment 1 is an example of what? a. Data encapsulation b. Same-layer interaction c. Adjacent-layer interaction d. OSI model e. All of these answers are correct.

B (Same-layer interaction) . Same-layer interaction occurs on multiple computers. The functions defined by that layer typically need to be accomplished by multiple computers—for example, the sender setting a sequence number for a segment, and the receiver acknowledging receipt of that segment. A single layer defines that process, but the implementation of that layer on multiple devices is required to accomplish the function.

A network engineer spends time thinking about the entire Class B network 172.16.0.0, and how to subnet that network. He then chooses how to subnet this Class B network and creates an addressing and subnetting plan, on paper, showing his choices. If you compare his thoughts about this network before subnetting the network, to his thoughts about this network after mentally subnetting the network, which of the following occurred to the parts of the structure of addresses in this network? a. The subnet part got smaller. b. The host part got smaller. c. The network part got smaller. d. The host part was removed. e. The network part was removed.

B (The host part got smaller.) . An unsubnetted Class A, B, or C network has two parts: the network and host parts. To perform subnetting, the engineer creates a new subnet part by borrowing host bits, shrinking the number of host bits. The subnet part of the address structure exists only after the engineer chooses a nondefault mask. The network part remains a constant size.

Which of the following are true about IP address 172.16.99.45's IP network? (Select two answers.) a. The network ID is 172.0.0.0. b. The network is a Class B network. c. The default mask for the network is 255.255.255.0. d. The number of host bits in the unsubnetted network is 16.

B (The network is a Class B network.) and D (The number of host bits in the unsubnetted network is 16. ) . The first octet (172) is in the range of values for Class B addresses (128-191). As a result, the network ID can be formed by copying the first two octets (172.16) and writing 0s for the last two octets (172.16.0.0). The default mask for all Class B networks is 255.255.0.0, and the number of host bits in all unsubnetted Class B networks is 16.

An engineer is thinking about the following IP address and mask using classless IP addressing logic: 10.55.66.77, 255.255.255.0. Which of the following statements are true when using classless addressing logic? (Choose two.) a. The network part's size is 8 bits. b. The prefix length is 24 bits. c. The prefix length is 16 bits. d. The host part's size is 8 bits.

B (The prefix length is 24 bits.) and D (The host part's size is 8 bits. ) . Classless addressing rules define a two-part IP address structure: the prefix and the host part. The host part is defined the same way as with classful IP addressing rules. The classless address rules' prefix length is the length of the combined network and subnet parts when using classful IP addressing concepts. Mathematically, the prefix length is equal to the number of binary 1s in the mask. In this case, with a mask of 255.255.255.0, the prefix length is 24 bits. The host length is the number of bits added to 24 to total 32, for 8 host bits.

Which of the following answers lists the prefix (CIDR) format equivalent of 255.255.254.0? a. /19 b. /20 c. /23 d. /24 e. /25

C (/23). Thinking about the conversion one octet at a time, the first two octets each convert to 8 binary 1s. 254 converts to 8-bit binary 11111110, and decimal 0 converts to 8-bit binary 00000000. So, the total number of binary 1s (which defines the prefix length) is 8+8+7+0 = /23.

Which of the following answers lists the dotted-decimal notation (DDN) equivalent of /24? a. 255.255.240.0 b. 255.255.252.0 c. 255.255.255.0 d. 255.255.255.192 e. 255.255.255.240

C (255.255.255.0) . /24 is the equivalent of the mask that in binary has 24 binary 1s. To convert that to DDN format, write down all the binary 1s (24 in this case), followed by binary 0s for the remainder of the 32-bit mask. Then take 8 bits at a time, and convert from binary to decimal (or memorize the nine possible DDN mask octet values and their binary equivalents). Using the /24 mask in this question, the binary mask is 11111111 11111111 11111111 00000000. Each of the first three octets is all binary 1, so each converts to 255. The last octet, all binary 0s, converts to decimal 0, for a DDN mask of 255.255.255.0. See Appendix A for a decimal/binary conversion table.

Working at the help desk, you receive a call and learn a user's PC IP address and mask (10.55.66.77, mask 255.255.255.0). When thinking about this using classful logic, you determine the number of network (N), subnet (S), and host (H) bits. Which of the following is true in this case? a. N=12 b. S=12 c. H=8 d. S=8 e. N=24

C (H=8) . The size of the network part is always either 8, 16, or 24 bits, based on whether it is Class A, B, or C, respectively. As a Class A address, N=8. The mask 255.255.255.0, converted to prefix format, is /24. The number of subnet bits is the difference between the prefix length (24) and N, so S=16 in this case. The size of the host part is a number that, when added to the prefix length (24), gives you 32, so H=8 in this case.

Which of the following statements describes part of the process of how a LAN switch decides to forward a frame destined for a broadcast MAC address? a. It compares the unicast destination address to the bridging, or MAC address, table. b. It compares the unicast source address to the bridging, or MAC address, table. c. It forwards the frame out all interfaces in the same VLAN except for the incoming interface. d. It compares the destination IP address to the destination MAC address.

C (It forwards the frame out all interfaces in the same VLAN except for the incoming interface.) . A switch floods broadcast frames, multicast frames (if no multicast optimizations are enabled), and unknown unicast destination frames (frames whose destination MAC address is not in the MAC address table).

Which OSI layer defines the functions of logical network-wide addressing and routing? a. Layer 1 b. Layer 2 c. Layer 3 d. Layer 4 e. Layer 5, 6, or 7

C (Layer 3) . The network layer concerns itself with delivery of data over the complete end-to-end path. That requires a way to identify each device, using addresses, and the addresses must be logical addresses that are therefore not tied to the physical details of the network.

Which of the following terms are not used to reference the one number in each subnet used to uniquely identify the subnet? (Select two answers.) a. Subnet ID b. Subnet number c. Subnet broadcast d. Subnet name e. Subnet address

C (Subnet broadcast) and D (Subnet name) . Subnet ID (short for subnet identifier), subnet address, and subnet number are all synonyms and refer to the number that identifies the subnet. The actual value is a dotted-decimal number, so the term subnet name does not apply. The term subnet broadcast, a synonym for the subnet broadcast address, refers to the last (highest) numeric value in a subnet.

Which of the following is a network broadcast address? a. 10.1.255.255 b. 192.168.255.1 c. 224.1.1.255 d. 172.30.255.25

D (172.30.255.255 ) . To find the network broadcast address, first determine the class, and then determine the number of host octets. At that point, convert the host octets to 255 to create the network broadcast address. In this case, 10.1.255.255 is in a Class A network, with the last three octets as host octets, for a network broadcast address of 10.255.255.255. For 192.168.255.1, it is a Class C address, with the last octet as the host part, for a network broadcast address of 192.168.255.255. Address 224.1.1.255 is a class D address, so it is not in any unicast IP network, so the question does not apply. For 172.30.255.255, it is a Class B address, with the last two octets as host octets, so the network broadcast address is 172.30.255.255.

Imagine a switch with three configured VLANs. How many IP subnets are required, assuming that all hosts in all VLANs want to use TCP/IP? a. 0 b. 1 c. 2 d. 3 e. You can't tell from the information provided.

D (3) . Although a subnet and a VLAN are not equivalent concepts, the devices in one VLAN are typically in the same IP subnet and vice versa.

Which of the following statements is true about classless IP addressing concepts? a. Uses a 128-bit IP address b. Applies only for Class A and B networks c. Separates IP addresses into network, subnet, and host parts d. Ignores Class A, B, and C network rules

D (Ignores Class A, B, and C network rules ) . Classless addressing rules define a two-part IP address structure: the prefix and the host part. This logic ignores Class A, B, and C rules, and can be applied to the 32-bit IPv4 addresses from any address class. By ignoring Class A, B, and C rules, classless addressing ignores any distinction as to the network part of an IPv4 address.

Why does the formula for the number of hosts per subnet (2H - 2) require the subtraction of two hosts? a. To reserve two addresses for redundant default gateways (routers) b. To reserve the two addresses required for DHCP operation c. To reserve addresses for the subnet ID and default gateway (router) d. To reserve addresses for the subnet broadcast address and subnet ID

D (To reserve addresses for the subnet broadcast address and subnet ID). By definition, two address values in every IPv4 subnet cannot be used as host IPv4 addresses: the first (lowest) numeric value in the subnet for the subnet ID, and the last (highest) numeric value in the subnet for the subnet broadcast address.

Which of the following protocols are examples of TCP/IP transport layer protocols? (Choose two answers.) a. Ethernet b. HTTP c. IP d. UDP e. SMTP f. TCP

D (UDP) and F (TCP). Of the remaining answers, Ethernet defines both physical and data link protocols, PPP is a data link protocol, IP is a network layer protocol, and SMTP and HTTP are application layer protocols.

Which of the following terms is used specifically to identify the entity created when encapsulating data inside data link layer headers and trailers? a. Data b. Chunk c. Segment d. Frame e. Packet

D(Frame) . By convention, the term frame refers to the part of a network message that includes the data link header and trailer, with encapsulated data. The term packet omits the data link header and trailer, leaving the network layer header with its encapsulated data. The term segment omits the network layer header, leaving the transport layer header and its encapsulated data.

Which of the following are not valid Class B network IDs? a. 130.0.0.0 b. 191.255.0.0 c. 128.0.0.0 d. 150.255.0.0 e. All are valid Class B network IDs

E (All are valid Class B network IDs) . Class B networks all begin with values between 128 and 191, inclusive, in their first octets. The network ID has any value in the 128-191 range in the first octet, and any value from 0-255 inclusive in the second octet, with decimal 0s in the final two octets. Two of the answers show a 255 in the second octet, which is acceptable. Two of the answers show a 0 in the second octet, which is also acceptable.