Subnet Design Exercise
For the US holiday weekend, I thought I’d leave you with a design exercise that requires a little more thought than most of my exercise posts. In this case, you’ll start with a class B network, and a set of requirements. Your job: to come up with an IP subnetting design. You choose the mask, find all the subnets, choose the subnets, pick IP addresses from each subnet, and create the ip address commands on the routers. Answer after the fireworks next Monday. Enjoy, and for you US folks, happy Independence day!
You need to design and pick subnets for the following small internetwork:
The figure shows the required number of hosts that need to be supported. Your design should meet the following requirements:
- Choose 1 mask, and only one mask, to be used for all subnets
- Choose the 1 mask that meets the requirements while using the least number of host bits
- Assign the WAN subnets as the numerically lowest subnets from the list of possible subnets; the R1-R2 link with the lowest, and the R2-R3 link with the next lowest.
- Assign the LAN subnets with the three numerically highest subnet IDs; R1’s LAN with the highest, R2’s LAN next, and then R3’s LAN.
- Choose IP addresses for the router as the highest IP addresses in each subnet. On the WAN links, which have mlutiple router IP addresses in one subnet, give the highest IP address to the router with the higher router number (eg, R2 gets a higher IP address than R1)
I believe those requirements paint you into a corner well enough so that there is only one solution; if not, and my solution is different than yours, but you think yours is also valid, feel free to post. Also, post any clarifying questions you like before I post the answer.