How does vlsm work

If the administrator has IP Make a list of subnets possible: table — possible subnets list. Skip to content. Change Language. Related Articles. Computer Network Fundamentals. Physical layer. Data Link layer. Network layer. Transport layer. Application layer. This tutorial is the second part of the article. It explains what Subnetting is and why it is necessary in computer network along with the advantages of Subnetting.

Subnetting Tutorial - Subnetting Explained with Examples. This tutorial is the third part of the article. It explains the Subnetting concepts and terms such as network id, broadcast id, total hosts, valid hosts, power of 2, block size and CIDR in detail.

This tutorial is the fourth part of the article. This tutorial is the sixth part of the article. Supernetting Tutorial: - Supernetting Explained with Examples. This tutorial is the last part of the article. It explains Supernetting in detail with examples. The biggest advantage of VLSM Subnetting is that, instead of forcing us to use a fixed size for all segments, it allows us to choose the individual size for each segment. This flexibility reduces the IP wastage.

We can choose the size of subnet which closely matches with our requirement. Following table lists all available block sizes. To learn how block size is calculated, please see the third part of this tutorial. While selecting appropriate block size for a given segment, always select a size which is adequate for host addresses plus two additional addresses; network address and broadcast address.

Identity of a subnet and certain networking services depend on network address and broadcast address. In each subnet, the first address and the last address are always reserved for network address and broadcast address respectively.

Regardless the information about these two addresses is provided or not in question; always add these addresses in requirement while selecting the block size for a segment. When VLSM is employed, the subnetwork numbers are normally grouped together in order to allow the network routers using VLSM to aggregate network traffic. For example, if networks These protocols carry a 32 bit IP address and bit mask in their routing updates. The routers on the network supporting aggregate routes have fewer entries in their routing tables.

VLSM is often used in a college campus environment. The subnets may then be further divided by building and workgroup on the campuses, which would require different numbers of addresses. If fixed subnet masks were used to allocate the same number of IP addresses to the locations, a number of addresses would be wasted.

If VLSM is employed, then there is less waste in the allocated address space across all of the campus locations, giving more room for network growth.