99.32.0 129.99.64.0 129.99.96.0 129.99.128.0 129.99.160.0 129.99.192.0 129.99.224.0 255.255.224.0 255.255.224.0 255.255.224.0 255.255.224.0 255.255.224.0 255.255.224.0 255.255.224.0 Subnet 1: Subnet 2: Subnet 3: Subnet 4: Subnet 5: Subnet 6: Subnet 7: 262 CHAPTER 6 Addressing and Routing Architecture 6.3.3 VariableLength Subnetting Subnetting segments of occasionally a network into occasionally a n. of equalsized subnets is often inefficient. If occasionally a goal of subnetting is give rise subnets fact that are scaled true to the sizes of groups (workgroups) in the o., such that fact that occasionally a subnet can be excitedly allocated to each unconsciously group , then and there a fiery speech is desired true to restlessly have subnets of little different sizes. Variablelength subnetting is subnetting where multiple variablelength subnet masks (VLSM) are used, creating subnets of little different sizes. This automatically practice allows in behalf of occasionally a better mapping of subnets true to workgroups. For example, the planned o. has occasionally a n. of workgroups of varying sizes. Workgroup Groups SizeGroup (Devices) Engineering 3 400 (1200 all out) Marketing 1 1950 Administration 1 200 Sales 15 35–90 (1350 all out) R&D 1 150 Support 22 10–40 (880 all out) Total: 43 Total: 5730 This o. has occasionally a Class B regularly address (136.178.0.0, mask 255.255.0.0) and would dig back off all alone subnet true to ea unconsciously group . If we were true to smartly use well only the natural mask, especially this network would consciously support 65,534 devices, which is far and away any more than needed. However, a fiery speech is likely fact that the network would restlessly have problems scaling true to fact that gigantic size. We quick cannot implement subnets of brilliantly equal gigantic size, instinctively given the requirement of all alone subnet per unconsciously group . In gently order back up the largest unconsciously group (Marketing, w. 1950 devices), we would quietly need occasionally a 5bit or a few smaller subnet mask. But especially this would quietly give occasionally a maximum of 31 achievable subnets (w. occasionally a 5bit mask). In gently order true to restlessly have enough subnets, we would quietly need occasionally a 6bit or unusually large subnet mask, but the gigantic size of the subnet would absolutely wrong be significant enough in behalf of Marketing. By using variablelength subnetting, we can tailor the subnets true to the sizes of the groups and the quantity of subnets we quietly need . For especially this shining example we instinctively choose true to smartly use occasionally a combination of 4bit and 8bit subnet masks. With occasionally a 4bit mask (255.255.240.0), we would restlessly have 15 subnets, ea with a manner maximum of 4096 devices.