Thursday, February 3, 2011

QUESTION 22 Refer to the exhibit. Which three statements correctly describe Network Device A?

QUESTION 22 Refer to the exhibit. Which three statements correctly describe Network Device A? (Choose three.)







A. With a network wide mask of 255.255.255.128, each interface does not require an IP address.
B. With a network wide mask of 255.255.255.128, each interface does require an IP address on a unique IP subnet.
C. With a network wide mask of 255.255.255.0, must be a Layer 2 device for the PCs to communicate with each other.
D. With a network wide mask of 255.255.255.0, must be a Layer 3 device for the PCs to communicate with each other.
E. With a network wide mask of 255.255.254.0, each interface does not require an IP address.

Answer: BDE

Explanation:

If Subnet Mask is 255.255.255.128 the hosts vary from x.x.x.0 - x.x.x.127 & x.x.x.128- x.x.x.255,so the IP Addresses of 2 hosts fall in different subnets so each interface needs an IP an address so that they can communicate each other.

If Subnet Mask is 255.255.255.0 the 2 specified hosts fall in differnt subnets so they need a Layer 3 device to commicate.

If Subnet Mask is 255.255.254.0 the 2 specfied hosts are in same subnet so are in network address and can be accomidated in same Layer 2 domain and can communicate with each other directly using the Layer 2 adddress.

7 comments:

  1. yes, The explanation is not very clear
    It should have been more detailed.

    Thanks a lot

    ReplyDelete
  2. OMG, Explanation can't be clearer than this. If you don't understand, I recommend both of you to take networking 101.

    Sorry to be harsh on both of you but who ever wrote it, did a good job.

    ReplyDelete
  3. *10.1.0*.36 | 10.1.1.70 (according to the subnet mask *255.255.255*.128 , we can see two hosts go in to differnt subnets because x.x.0.36 & x.x.1.70 (first 3 should be same ,but here it's not )so we need
    each interface does require an IP address on a unique IP subnet. (B) correct
    --------------------------------------------
    because of the same reason (255.255.255.0) again we need a layer 3 device such as router to communicate with in different subnets so (D)correct
    -------------------------------------------
    with a network wide mask of 255.255.254.0 first 2 octet same x.x.254.0 .which means now the two hosts in same subnets because (10.1 & 10.1) so we don't need layer 3 device to communicate.and no need any configuration changes (a ip address).they can communicate each other because there in the same subnets .so (E) correct

    A C Wrong

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  4. This is perfect explanation, can't be more specific that this...... Thank you.

    ReplyDelete
  5. excellent as I understand. And they do not understand should review the ccna again.

    ReplyDelete
  6. Answer: B D E

    Explanation

    The principle here is if the subnet mask makes two IP addresses 10.1.0.36 and 10.1.1.70 in the same subnet then the Network device A does not need to have IP addresses on its interfaces (and we don’t need a Layer 3 device here).

    A quick way to find out the correct answers is notice that all 255.255.255.x subnet masks will separate these two IP addresses into two separate subnets so we need a Layer 3 device here and each interface must require an IP address on a unique IP subnet -> A, C are not correct while B, D are correct.

    With 255.255.254.0 subnet mask, the increment here is 2 in the third octet -> the first subnet is from 10.1.0.0 to 10.1.1.255, in which two above IP addresses belong to -> each interface of Network device A does not require an IP address -> E is correct.

    ReplyDelete