Task 1:

• Configure R1 with the first usable host IP address in the IPv4 network.
• Configure R2 with the last usable host IP address in the IPv4 network.
• Verify connectivity using ping.

For a /28 network 192.168.168.192, the subnet spans from .192 to .207.

• .192 = network address
• .207 = broadcast address

Usable hosts range from .193 to .206. We will assign the first usable address (.193) to R1�s G0/1 and the last usable address (.206) to R2�s G0/1, then verify with ping.

On R1:

R1# configure terminal
R1(config)# interface g0/1
R1(config-if)# ip address 192.168.168.193 255.255.255.240
R1(config-if)# no shutdown
R1(config-if)# exit

ip address 192.168.168.193 255.255.255.240: Sets g0/1 to the first usable address. /28 prefix length is equal to 255.255.255.240.
no shutdown: Enables the interface.

On R2:

R2# configure terminal
R2(config)# interface g0/1
R2(config-if)# ip address 192.168.168.206 255.255.255.240
R2(config-if)# no shutdown

ip address 192.168.168.206 255.255.255.240: Sets g0/1 to the last usable address. /28 prefix length is equal to 255.255.255.240.

Verification:

R1# ping 192.168.168.206
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.168.206, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms
 

Task 2:

• Do not assign the subnet router anycast address to either router.
• Configure R1 with the first usable host IP address in the IPv6 network.
• Configure R2 with the last usable host IP address in the IPv6 network.
• Verify connectivity using ping

For /125 network 2001:db8:12::60, the first address (2001:db8:12::60) is reserved for the subnet router anycast (similar to the "network address" in IPv4).

As IPv6 is 128 bit, /125 prefix length reserves 125 bits which means that only 3 bits are remaining for host addresses. 2³ -1(anycast) = 7, the remaining usable addresses range from 61 to 67.

R1 gets: 2001:db8:12::61/125 (first usable address)

R2 gets: 2001:db8:12::67/125 (last usable address)

On R1:

R1# configure terminal
R1(config)# interface g0/1
R1(config-if)# ipv6 address 2001:db8:12::61/125
R1(config-if)# exit

ipv6 address 2001:db8:12::61/125: Sets g0/1 to the first usable address.

On R2:

R2(config-if)# ipv6 address 2001:db8:12::67/125
R2(config-if)# exit

ipv6 address 2001:db8:12::67/125: Sets g0/1 to the last usable address.

Verification:

R1# ping 2001:db8:12::67
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2001:db8:12::67, timeout is 2 seconds:
.!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms

Save all configurations to NVRAM:

R1# write
R2# write