7 - Questions - TCP/IP Internet Layer

Which two IPv4 address blocks are assigned for use in documentation and example code? (Choose two.)

203.0.113.0/24 198.51.100.0/24

Which two statements about a network that uses subnetworks are true? (Choose two.)

Smaller networks are easier to manage. Overall traffic is reduced.

Which option correctly describes the network ID portion of the IPv4 address?

It identifies the network of which the host is a part.

What is the binary equivalent of the decimal number 192?

11000000

Which two IPv4 address classes are considered as special cases, and are never assigned to hosts as source IPv4 addresses? (Choose two.)

Class D Class E

How many bits are contained in an IPv4 address?

The correct answer is "32 bits." IPv4 addresses are essentially 32-bit binary numbers.

What is the decimal representation of 01000000?

64

You have been assigned the network address 192.168.7.0/24. You assume that you need to establish 13 subnets, so you apply the subnet mask 255.255.255.240. What will be your second subnet address?

The correct answer is "192.168.7.16." To answer this question, remember that the first 24 bits of the address are already designated as network bits before subnetting. Therefore, the octets 192.168.7 will not change during subnetting. The first subnet is the 192.168.7.0 subnet, and because the value of the last bit borrowed for subnetting is 16 (as shown in the figure), you should increment by 16 to create each subsequent subnet address. That makes the second subnet address 192.168.7.16.

What is the decimal equivalent of the binary number 11100000?

The correct answer is "224." To calculate the decimal equivalent, look at the ones and zeros. Calculate the example 11100000 as: 128*1+64*1+32*1+16*0+8*0+4*0+2*0+1*0=224.

How many host addresses can be used in a network with a /24 mask that has not been subnetted?

The correct answer is "254." Number of hosts equals 2 powered by the number of host bits minus 2; 2^8-2 = 254.

You have been assigned the network 172.16.0.0/16. You need to establish 13 subnets. What is the new subnet mask in the decimal form?

The correct answer is "255.255.240.0." To get 13 subnets, you must borrow 4 host bits from the third octet. If you add the values of those 4 bits, you get the decimal number 240, so the new subnet mask is 255.255.240.0.

A company currently has a network range of 192.168.54.0/24. The company wants to subnet this range into 4 subnets, each supporting at least 30 users. Which subnet mask would you recommend?

The correct answer is "255.255.255.192." To create four subnets, you must borrow the two left-most host bits from the fourth octet. If you add the values of those 2 bits, you get the decimal number 192, so the new subnet mask is 255.255.255.192.

How many subnets and how many host addresses per subnet are created by borrowing 8 bits from a 172.16.0.0/16 network?

The correct answer is "256 subnets with 254 host addresses per subnet." To subnet 172.16.0.0/16, you must borrow bits from the third octet, moving left to right and borrowing each consecutive bit. To determine how many subnets are created by borrowing 8 bits from the third octet, count the 8 bits by powers of two, starting with the left-most borrowed bit. Begin with 2 and increase by powers of two. To determine how many valid host addresses are available, count the eight remaining host bits by powers of two, starting with the far-right bit. Begin with 2 and increase by powers of two, then subtract two.

Which CLI command should you use to verify the IPv4 address on a Windows computer?

The correct answer is "ipconfig." You would use the ipconfig command to display all current TCP/IP network configuration values.

Which type of reserved IPv4 address is 127.0.0.1?

The correct answer is "loopback."A typical local loopback IP address is 127.0.0.1. On a Microsoft Windows host, you can ping any IP address in the 127.0.0.0/8 range.

Determine which class the IPv4 address 172.32.11.7 belongs to and whether it belongs to the range of the public or private IPv4 addresses. Which option represents the correct description?

The correct answer is "public, Class B." The IP address 172.32.11.7 is a Class B address. This IP address does not fall within the range of private IP addresses that are specified in RFC 1918.

Which option correctly describes the service type field in the IPv4 header?

It provides information on the desired quality of service.

Which two aspects can present a problem with a flat network design? (Choose two.)

Larger amounts of broadcast traffic consume resources. All devices share the same broadcast domain.

Which two approaches should you use to verify the IPv4 address on Apple Mac computer? (Choose two.)

Open the Terminal and use the ifconfig command. Choose System Preferences > Network and choose the desired connection.

Refer to the figure. Which two subnet addresses should be used for Subnets 1 and 2? (Choose two.)

The correct answers are "Subnet 1: 192.168.1.128/25" and "Subnet 2: 192.168.1.0/30." Subnet 1 requires a 25-bit subnet mask to support 100 hosts. Subnet 2 requires only 2 host addresses, and a 30-bit subnet mask provides exactly 2. Of the available answer options that use a 30-bit mask, only 192.168.1.0/30 is a valid subnet address. The addresses 192.168.1.112/25, 192.168.1.10/30, and 192.168.1.70/30 are not valid subnet addresses.

Determine which class the IPv4 address 10.71.121.31 belongs to and whether it belongs to the range of the public or private IPv4 addresses. Which option represents the correct description?

private, Class A

At which layer of the OSI reference model does IP operate?

network layer

What advantage do subnetworks provide?

scalability

Which option correctly defines the digits that are used in the binary number system?

1 and 0

You have subnetted your 192.168.36.0 network address with a 255.255.255.240 mask. How many subnets and hosts per subnet are available?

16 subnets and 14 hosts per subnet

You are designing an IPv4 addressing scheme for a branch office. The branch office is assigned to the 172.16.32.0/25 subnetwork, so you have one subnet (172.16.32.0) with 126 host addresses that are available to you. However, from your design branch office topology you can see that the largest LAN will only require 11 host addresses. If you want to avoid wasting address space and allocate addresses efficiently you will need to subnet your subnetwork further, which means applying the VLSM. Which subnet mask should you use to achieve the desired scheme?

255.255.255.240

How many valid host addresses are available for each subnet after subnetting network 192.168.0.0/24 by borrowing two host bits?

62

Which option is the binary representation of 80?

The correct answer is "01010000." The binary representation of 80 is 01010000.

You want to subnet your 10.0.0.0/8 network to create 31 subnets. You determine that you need to apply the subnet mask 255.248.0.0. What is the range of available host addresses for the first subnet?

The correct answer is "10.0.0.1 to 10.7.255.254." Two pieces of information in the question tell you that five host bits have been borrowed for subnetting. First, the creation of 31 subnets requires 5 host bits, and second, the value of 248 in the second octet of the subnet mask indicates that 5 host bits have been borrowed. That means that the value of the last bit borrowed is 8. Therefore, the second subnet would be 10.8.0.0, making the valid host range for the first subnet 10.0.0.1 to 10.7.255.254. The address 10.7.255.255 could not be used as a host address because it is the broadcast address for the first subnet.

What is the binary equivalent of the decimal number 183?

The correct answer is "10110111." The 128*1+64*0+32*1+16*1+8*0+4*1+2*1+1*1=183 calculation gives you binary 10110111.

Which option is the decimal representation of 10000000?

The correct answer is "128." According to the binary-to-decimal conversion method, the left-most value represents 27, which equals 128.

How many valid host addresses are available for each subnet after subnetting network 172.16.0.0/16 by borrowing two host bits?

The correct answer is "16382." Borrowing two host bits from the third octet for subnetting leaves the right-most 14 bits for host addresses. To determine how many valid host addresses are available, count the 14 host bits by powers of two, starting with the far-right bit. Begin with 2 and increase by powers of two, then subtract two.

Which of these addresses is the assigned subnet address for the host address 192.168.3.50/27?

The correct answer is "192.168.3.32." The 27-bit subnet mask means that three host bits have been borrowed from the last octet for subnetting. Therefore, the value of the last borrowed bit is 32. So, you get the following subnets: 192.168.3.0, 192.168.3.32, 192.168.3.64, and so on. The host address 192.168.3.50 falls within the 192.168.3.32 subnet.

You have a host 192.168.50.2/24. What is its network address?

The correct answer is "192.168.50.0" Given an IPv4 address and a subnet mask, you can calculate the network address by using the AND function between the binary representation of the IPv4 address and the binary representation of the subnet mask. The binary equivalent of the 192.168.50.2 address is 1100000.10101000.00110010.00000010. The subnet mask in binary is 11111111.11111111.11111111.00000000, which in decimal translates to 255.255.255.0. The result of binary AND operation is 1100000.10101000.00110010.00000000, which in decimal translates to 192.168.50.0.

A large company has a /8 network but needs to subnet it into 1000 subnets. Which subnet mask segments the /8 network and provides the maximum number of hosts per subnet?

The correct answer is "255.255.192.0." To subnet a /8 network, you must begin borrowing host bits from the second octet. To determine how many bits to borrow to create 1000 subnets, count the bits by powers of two, starting with the far-left bit. Begin with 2 and increase by powers of two. Borrowing one host bit enables you to create two subnets, borrowing 2 bits gives you four subnets, and so on. You will discover that borrowing all the bits from the second octet and 2 bits from the third octet creates 1024 subnets. If you add the values of all 8 bits in the second octet, you get 255, so the subnet mask for that octet is 255. If you add the values of the 2 bits that you borrowed in the third octet, you get 192. Therefore, the subnet mask that segments the /8 network and provides the maximum number of hosts per subnet is 255.255.192.0.

Which subnet mask would limit the number of hosts on any given subnet to 2046?

The correct answer is "255.255.248.0." Counting host bits by powers of two from right to left indicates that 11 bits are needed to allow for 2046 hosts per subnet (211 = 2048; 2048 - 2 = 2046). Using 11 bits for host addresses means that the first 21 bits of the 32-bit subnet mask are turned on. This way, the subnet mask is 11111111.11111111.11111000.00000000, or 255.255.248.0. The subnet masks 255.248.0.0 and 255.255.240.0 also allow 2046 hosts per subnet, but only the 255.255.248.0 mask limits the number of hosts per subnet to 2046.

You have been assigned a /24 network address. A coworker has requested that you create 10 subnets that can support 10 hosts per network. Which subnet mask should you use?

The correct answer is "255.255.255.240." To create 10 subnets, you had to borrow four 4 bits from the fourth octet. The sum of the values of those bits is 240, so you must use the subnet mask 255.255.255.240.

You are designing an IPv4 addressing scheme for a branch office. The branch office is assigned to the 192.168.1.64/26 subnetwork, so you have one subnet (192.168.1.64) with 62 host addresses that are available to you. You need at least 4 subnets with 14 hosts each. Which subnet mask should you use to achieve the desired scheme?

The correct answer is "255.255.255.240." You currently have a 26-bit subnet mask, 11111111.11111111.11111111.11000000. To obtain 4 subnets of 14 hosts each on your subnet, you need to apply VLSM (further subnet your subnet). To do so, continue borrowing host bits from the fourth octet, as was done in the original subnetting. Borrowing 2 additional host bits (11111111.11111111.11111111.11110000) creates the 4 subnets that you need and allows for 14 hosts per subnet. The binary subnet mask 11111111.11111111.11111111.11110000 translates to 255.255.255.240 in decimal.

You have subnetted your 192.168.36.0 network address with a 255.255.255.224 mask. How many subnets are available?

The correct answer is "8." There are 8 usable subnets and 30 hosts per subnet. The value of 224 in the subnet mask tells you that three host bits were borrowed from the fourth octet for subnetting. To determine how many subnets are created by borrowing 3 bits, count the bits by powers of two, starting with the far-left bit. Begin with 2 and increase by powers of two. To determine how many valid host addresses are available, count the five remaining host bits by powers of two, starting with the far-right bit. Begin with 2 and increase by powers of two, then subtract two.

By borrowing three host bits, how many subnets are created?

The correct answer is "8." To determine how many subnets are created by borrowing a given number of bits, count the bits by powers of two. Starting with the far-left bit, begin with 2 (21) and increase by powers of two. Borrowing one host bit enables you to create 2 subnets, borrowing 2 bits gives you 4 subnets, and borrowing 3 bits gives you 8 subnets.

Which IPv4 address class is dedicated for multicast?

The correct answer is "Class D." Class D (multicast) IP addresses are dedicated to multicast applications such as streaming media.

What is a possible problem within a broadcast domain?

The correct answer is "Larger amounts of broadcast traffic consume resources." A broadcast domain is a network in which all devices can reach each other by broadcast and if there is a large amount of broadcast traffic this can impose a considerable pressure on the available resources.

What does the TTL value (in the TTL field) represent?

The correct answer is "The TTL value limits the lifetime of a packet." The Time to Live (TTL) value limits the lifetime of a packet. The Total Length field describes the length of a packet, IHL describes the length of the header, and Fragment Offset indicates where a specific fragment belongs.

Which number system is the foundation of all computer operations?

The correct answer is "binary." The decimal (base 10) system is the numbering system used in everyday mathematics, and the binary (base 2) system is the foundation of all computer operations.

At which layer of the TCP/IP stack does IP operate?

The correct answer is "internet layer." IP operates at the internet layer of the TCP/IP stack and Layer 3 of the OSI reference model (network layer).