A network engineer must configure two new subnets using the address block 10.70.128.0/19 to meet these requirements:
-> The first subnet must support 24 hosts.
-> The second subnet must support 472 hosts.
-> Both subnets must use the longest subnet mask possible from the address block.
Which two configurations must be used to configure the new subnets and meet a requirement to use the first available address in each subnet for the router interfaces? (Choose two.)
Click on the arrows to vote for the correct answerA. B. C. D. E.
To configure the two subnets, the network engineer must first determine the network requirements to select the appropriate subnet mask and then create VLAN interfaces for the subnets on the Cisco device. The two subnets must support 24 and 472 hosts, respectively, using the longest subnet mask possible from the given address block 10.70.128.0/19.
To determine the subnet mask, the engineer needs to find the number of bits required to support the maximum number of hosts for each subnet. For the first subnet, 24 hosts require 5 host bits, leaving 11 network bits. For the second subnet, 472 hosts require 9 host bits, leaving 10 network bits.
To use the longest subnet mask possible, the engineer should allocate the remaining bits from the /19 network address block to each subnet. The /19 network address block has 13 network bits and 19-13=6 host bits. Allocating 11 bits to the first subnet leaves 2 bits for the host portion of the IP address, and allocating 10 bits to the second subnet leaves 6 bits for the host portion of the IP address.
Therefore, the first subnet should have a subnet mask of 255.255.248.0 (/21), and the second subnet should have a subnet mask of 255.255.252.0 (/22).
Now, the engineer needs to configure VLAN interfaces for each subnet on the Cisco device, using the first available IP address for the router interface. The VLAN interface IP addresses should belong to the respective subnets and use the subnet masks determined above.
Option A and D are correct, as they use the correct subnet mask for the respective subnets and assign the first available IP address in each subnet to the VLAN interface.
Option B and E are incorrect, as they do not use the correct subnet mask for the respective subnets.
Option C is incorrect, as it uses the correct subnet mask for the second subnet but assigns an incorrect IP address that does not belong to the subnet.
Therefore, the correct answers are A and D.