ICND1 100-101 Official Cert Guide

rob42rob42 Posts: 423Member
Hello fellow members.

Please be kind to me; I'm new to both the the subject of computer networking as well as the etiquette of this forum.

I've had a look around, but can see know sign of any subject in connection to my query which is in regard to the ICND1 100-101 Official Cert Guide (as you'll have gathered from the title of this thread) and more precisely, question 6 on page 307.

For anyone that does not have access to the book, the question is as follows...
Before Class B network 172.16.0.0 is subnetted by a network engineer, what parts of the structure of the IP address in this network already exist, with a specific size? (Select two answers)

a. Network
b. Subnet
c. Host
d. BroadcastTo my mind (and this is where I need your help as it seems, based on the answer given on page 308, that I'm wrong) the answers are 'b' & 'c', with a possibility of 'a'. I went with 'b' rather than 'a' as my understanding is that any network has a minimum of one Subnet and satisfies that question of already existing and of a specific size (although this is also applicable to 'a') and the chapter is about Subnetting.

The answer given on page 308 is 'a' & 'c', and I don't understand why 'b' is incorrect. Could anyone please explain to me why 'b' is an incorrect answer?

Posted with thanks.
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Comments

  • sillymcnastysillymcnasty Posts: 254Member ■■■□□□□□□□
    rob42 wrote: »
    Hello fellow members.

    Please be kind to me; I'm new to both the the subject of computer networking as well as the etiquette of this forum.

    I've had a look around, but can see know sign of any subject in connection to my query which is in regard to the ICND1 100-101 Official Cert Guide (as you'll have gathered from the title of this thread) and more precisely, question 6 on page 307.

    For anyone that does not have access to the book, the question is as follows...
    Before Class B network 172.16.0.0 is subnetted by a network engineer, what parts of the structure of the IP address in this network already exist, with a specific size? (Select two answers)

    a. Network
    b. Subnet
    c. Host
    d. BroadcastTo my mind (and this is where I need your help as it seems, based on the answer given on page 308, that I'm wrong) the answers are 'b' & 'c', with a possibility of 'a'. I went with 'b' rather than 'a' as my understanding is that any network has a minimum of one Subnet and satisfies that question of already existing and of a specific size (although this is also applicable to 'a') and the chapter is about Subnetting.

    The answer given on page 308 is 'a' & 'c', and I don't understand why 'b' is incorrect. Could anyone please explain to me why 'b' is an incorrect answer?

    Posted with thanks.


    My assumption is Network Bits and Host bits. It is asking about the structure. Subnets and hosts are more about individual IPs. Class B this has 16 network bits followed by 16 host bits.


    Edit: The answers are in the appendix. Here it is from the text: "6. A and C. An unsubnetted Class A, B, or C network has two parts: the network and host parts."
  • clarsonclarson Posts: 897Member ■■■■□□□□□□
    you always have your network bits and hosts bits.

    when using subnets, the subnet bits are taken away from the hosts bits. this creates 3 address portions, the network, the subnet and hosts.
    but being the question is asked about before any subnetting is done, there is no subnet portion. That just leaves the network and hosts.
  • rob42rob42 Posts: 423Member
    Thank you for your replies; I'd forgotten to check the DVD Appendix.

    I see, we don't have any Subnet Bits with a natural Subnet Mask; only Network Bits and Host Bits. I'd assumed that we had Subnet Bits and Host Bits given that each network has at least one Subnetwork, and didn't apprecate that fact that we can have up to 3 address portions, not just 2.

    Thank you to you both for making that clear.
    No longer an active member
  • sillymcnastysillymcnasty Posts: 254Member ■■■□□□□□□□
    rob42 wrote: »
    Thank you for your replies; I'd forgotten to check the DVD Appendix.


    No problem. It is really strange to put the explanations so far from the original reading lol. I had to figure that one out
  • rob42rob42 Posts: 423Member
    No problem. It is really strange to put the explanations so far from the original reading lol. I had to figure that one out

    Cheers man; all the best with your studies.
    No longer an active member
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