This article is the third in a series of three which has been written for those who are, or may one day be responsible for designing an IP network.

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Sit back, take a deep breath and prepare for another of my techie articles, this time on how to configure Variable Length Subnet Masking (VLSM).

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VLSM’s are used to reduce the number of wanted IP Addresses in each subnet, allow for more subnets and avoid having to obtain another registered IP Address.Again the best way I have found to explain VLSM’s is to run through an example configuration

Example

Your company’s network has been assigned a Class A registered address of: 98.0.0.0 from this you need to create:

• Six subnets of 2000000 Hosts
• Thirty subnets of 64000 Hosts
• Fourteen subnets of 4000 Hosts

The default Class A subnet mask is 255.0.0.0, represented as / 8.

The best way to approach this is to work in stages calculating the different subnet requirements

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This article is the second in a series of three which has been written for those who are, or may one day be responsible for designing an IP network.

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Sit back, take a deep breath and prepare for another of my techie articles, this time on Super-netting, also known as Route Summarization or Route Aggregation

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Introduction

The larger the network the bigger the routing table, in large internet-works, hundreds, or even thousands, of network addresses can exist, this will result in each Router taking longer to process information and route packets.

Super-netting is designed to improve convergence time, increase performance and reduce the size of the routing table and the number of routes that a router has by grouping multiple networks together and representing them as a single summarized network in the routing table.

NOTE: Super-netting can only be used with classless routing protocols, these extend the standard Class A, B, or C IP addressing scheme by using a subnet mask or mask length to indicate how routers must interpret an IP network ID. Classless routing protocols include the subnet mask along with the IP address when advertising routing information.

I will admit that I love IP Addressing - sad I know, but true! The best way I have found to explain supernetting to my students is to run through an example configuration
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This article is the first in a series of three which has been written for those who are, or may one day be responsible for designing an IP network.

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Sit back, take a deep breath and prepare for one of my techie articles, this time on Sub-netting

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Introduction

IP Routing requires that each physical subnet within the Intranet (a network owned by a private organization) use’s a unique Network ID.

A large organization may have insufficient network addresses available for their needs.

IP Sub-netting creates larger numbers of smaller groups of IP Addresses called Subnets which can improve network security and increase performance by reducing the size of the broadcast domain

To sub-net, bits must be borrowed from the Host portion within a Subnet Mask.

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