Routing, Switching & Virtual LANs

1. Using VLSM, divide the network as efficiently as possible to meet the following requirements:-

• A subnet for LAN A with at most 62 useable addresses
• A subnet for LAN B with at most 30 useable addresses
• A separate subnet for the WAN link

          Q1 Answer

Here is one possible solution.

The largest subnet needs enough space for 44 hosts.

25 - 2 = 62 useable host addressess...

... which is the nearest size adequate for the this number of host addresses. So, the network can be divided as follows...

Subnet 0 can contain Lan A

Subnet 1 can be divided into two smaller subnets with 30 useable host addresses in each.

Sub-subnet 0 can contain Lan B

Part of Sub-subnet 1 can be divided further to contain the WAN link addresses. I.e. 193.100.4.120/30

So we will have...

Here is a diagramatic view of the network showing the subnet addresses.

1. Using VLSM, divide the network shown below as efficiently as possible to meet the following requirements:-

• A subnet for Net A with at most 126 useable addresses
• A subnet for Net B with at most 62 useable addresses
• A subnet for Net C large enough for 25 IP addresses
• A subnet for Net D large enough for 10 IP addresses
• A separate subnet for the WAN link

  
      Q1 Answer

Here is one possible solution for dividing the network into subnets...

Here is a diagramatic view of the network showing the subnet addresses.