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CCNA Exploration Chapter 9 Ethernet(3)

By Leonard Kelley,2014-06-17 08:14
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CCNA Exploration Chapter 9 Ethernet(3) ...

    CCNA Exploration Chapter 6 Addressing. Study questions. Answers in white font. Select and change colour to see them.

    Reminder just in case. 12 (2^1 or 2 to the power 1) = 2 22 (2^2 or 2 to the power 2) = 2 x 2 = 4 32 (2^3 or 2 to the power 3) = 2 x 2 x 2 = 8 42 (2^4 or 2 to the power 4) = 2 x 2 x 2 x 2 = 16 52 (2^5 or 2 to the power 5) = 2 x 2 x 2 x 2 x 2 = 32 62 (2^6 or 2 to the power 6) = 2 x 2 x 2 x 2 x 2 x 2 = 64 72 (2^7 or 2 to the power 7) = 2 x 2 x 2 x 2 x 2 x 2 x 2 = 128 82 (2^8 or 2 to the power 8) = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 = 256

6.1

    How is an IPv4 address normally written?

What is an octet?

The IP address is in two parts. The bits on the left (high order) represent the:

The bits on the right (low order) represent the:

    What is the largest number that can be held in one octet (8 bits)?

Convert the binary number 10011101 to decimal.

Convert the binary number 11110000 to decimal.

Convert the decimal number 224 to binary.

Convert the decimal number 200 to binary.

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Convert the IP address 192.168.20.15 to binary.

6.2

    What are the three types of IP address in the range of a network?

What information does the network prefix give?

    If a host IP address is 192.168.3.55 and the prefix length is /24, what are the network address and broadcast address of the host’s network?

    If a host IP address is 172.16.29.104 and the prefix length is /16, what are the network address and broadcast address of the host’s network?

    If a host IP address is 172.16.29.104 and the prefix length is /24, what are the network address and broadcast address of the host’s network?

    A host IP address is 201.37.16.9 and the prefix length is /28. How many bits of the last octet are in the network part of the address?

    The host address and prefix are the same as in the previous question. Write the last octet in binary showing all 8 bits.

    The host address and prefix are the same as before. The network address has all the bits in the host part set to 0. What is the last octet of the network address written in binary?

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    The host address and prefix are the same as before. What is the network address written as four octets of decimal?

    The host address and prefix are the same as before. The network address has all the bits in the host part set to 1. What is the last octet of the network address written in binary?

    The host address and prefix are the same as before. What is the broadcast address written as four octets of decimal?

    A host IP address is 201.37.16.19 and the prefix length is /28. What are the network address and the broadcast address of the host’s network?

    A host IP address is 201.37.16.19 and the prefix length is /28. What are the first and last host addresses of the network?

    A host IP address is 150.90.163.12 and the prefix length is /22. What are the network address and the broadcast address of the host’s network?

What is a unicast packet?

What is a broadcast packet?

What is a multicast packet?

    What destination IP address would a host use for a limited broadcast to hosts on its own network?

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    A host is using the broadcast address 192.168.1.255 to send a directed broadcast to hosts on the 192.168.1.0 network, which is the other side of a router. Will the broadcast reach the hosts?

Give three examples of the use of broadcast messages.

Which IPv4 addresses are used for multicasts?

    Which IPv4 addresses are not currently used to address hosts, but are reserved for experimental purposes?

    What is the difference between public addresses and private addresses?

What are the blocks of private addresses?

    What is the name of the service that can allow hosts on a network using private addresses to have the use of a public address or addresses to access the Internet?

    Why are hosts never given IP addresses with the first octet 0?

What is special about the address 127.0.0.1?

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    Which other addresses have special uses and are not routed over the Internet?

What is classful network addressing?

    In class A, how much of the IP address is in the network part, and what is the range of numbers in the first octet?

    In class B, how much of the IP address is in the network part, and what is the range of numbers in the first octet?

    In class C, how much of the IP address is in the network part, and what is the range of numbers in the first octet?

What are the subnet masks for class A, class B and class C?

    We now use classless addressing, so why is it still useful to learn about classful addressing?

6.3

    Give three reasons why the allocation of IP addresses in a company network should be planned and documented carefully.

    What is static IP addressing and which devices are normally given static addresses?

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    What is dynamic IP addressing and why is it used for the majority of workstations?

    Why should the host addresses within a network be split into blocks of adjacent addresses, with one block for workstations, one block for servers, one block for network devices etc?

    Which network address should be given to the default gateway?

What is IANA?

What was the main reason for developing IPv6?

    How many bits are in an IPv6 address, and how are they written?

What are the advantages of IPv6 over IPv4?

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6.4

    The subnet mask gives the same information as:

What does a binary 1 in the subnet mask mean?

What does a binary 0 in the subnet mask mean?

    A host is configured with a subnet mask 255.255.0.0. Write the subnet mask in binary and write down the prefix that gives the same information.

    Which decimal numbers can appear in subnet masks, and why?

    What results do you get from the following logical operations on bits? 0 AND 0 =

    1 AND 0 =

    0 AND 1 =

    1 AND 1 =

    If you take the IP address of a host and perform a bit-by-bit logical AND with the host’s subnet mask, what do you get?

    Why does the host that originates a message carry out the logical AND operation?

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    Which networking device carries out the logical AND, and why?

    A host has IP address 172.16.98.29 and subnet mask 255.255.255.0. What is the network address of the host’s network?

    A host has IP address 172.16.98.29 and subnet mask 255.255.0.0. What is the network address of the host’s network?

    A host has IP address 172.16.98.29 and subnet mask 255.255.255.240. What is the network address of the host’s network?

    A host has IP address 172.16.98.29 and subnet mask 255.255.248.0. What is the network address of the host’s network?

    There are many good subnet calculators available. Why are you learning to subnet and to carry out logical AND without a calculator?

6.5

    You start with the network 201.73.1.0/24. You borrow 2 bits from the host part for subnetting.

    How many subnets can you have?

    How many hosts can you have on each subnet?

    Give the network address with its prefix, subnet mask, broadcast address and range of host addresses for each subnet.

    (Try to work this out. Do not just copy answers from the curriculum.)

subnets

    hosts on each subnet

    Network address Subnet mask Broadcast address Host addresses

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    You start with the network 199.30.57.0/24. You need 5 subnets. How many bits will you borrow? How many subnets will this give you? How many hosts on each subnet?

    An organisation has 80 hosts in the London office, 20 hosts in Cardiff, 15 hosts in Belfast and 150 hosts in Edinburgh. There are 5 WAN links connecting the offices. You need to plan the addressing. There will be one subnet for each office and one for each WAN link. Where will you start when you divide up your address space into subnets?

Warning. Page 6.5.2 of the curriculum has a misprint.

    The formula for the number of usable hosts should be: nUsable hosts = 2 2 (or 2^n 2) and not Usable hosts = 2 n - 2

    Suppose that you have borrowed 2 host bits for subnetting to create 4 subnets. You now want to split one of the subnets into 2 smaller subnets. How can you do this?

What is another name for subnetting the subnets?

Why was this technique of subnetting the subnets introduced?

    What is the most efficient prefix for a point to point WAN link? And what is the equivalent subnet mask?

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    Use the online activities to practice calculations.

6.6

    You ping 127.0.0.1 and get a reply. What does this tell you?

    You ping the default gateway and get no reply. Does this mean that the default gateway address is wrong?

    What does traceroute tell you that ping does not?

What is the purpose of ICMP?

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