Hi.I'm reading the VLSM chapter on the ICND2 cert guide.Specifically the section for adding a new subnet to an existing VLSM design.
In the book It says only the second , third and fifth possible /23 subnets will overlap.I don't understand why the fourth subnet 172.16.6.0 doesn't overlap with the R3 Lan 172.16.6.0.Is there something I'm missing?
Table 5-5
First Five Possible /23 Subnets
Subnet Subnet Number Subnet Broadcast Address
First (zero) 172.16.0.0 172.16.1.255
Second 172.16.2.0 172.16.3.255
Third 172.16.4.0 172.16.5.255
Fourth 172.16.6.0 172.16.7.255
Fifth 172.16.8.0 172.16.9.255
Table 5-6
Existing Subnet IDs and Broadcast Addresses from Figure 5-3
Subnet Subnet Number Subnet Broadcast Address
R1 LAN 172.16.2.0 172.16.3.255
R2 LAN 172.16.4.0 172.16.5.255
R3 LAN 172.16.6.0 172.16.6.255
R1-R2 serial 172.16.9.0 172.16.9.3
R1-R3 serial 172.16.9.4 172.16.9.7
