• Welcome back! In this installment, we’re going to examine VLSM (Variable-Length Subnet Masking, RFC 1878), and how to use the subnetting shortcuts to solve VLSM problems. I’m sure that it won’t surprise you to know that we’ll need the powers of two chart: n = 8 7 6 5 4 3 2 1 2n = …   Read More

  • How many of you have ever used CME B-ACD (Basic Automatic Call Distribution)? This is a very popular feature within Cisco Unified CME for locations that don’t have the luxury of either having a Cisco...

  • In this, our final look at subnetting for now, we’ll examine more “find the subnet” problems, specifically those in which the subnet/host boundary lies within the second or third octets. Here is the powers of...

  • When we last left off we were discussing a Cisco NAC Framework scenario using a router. We had discussed the required configuration on the ACS server with ACLs and Attribute Definition Files. But we cannot just get away with only configuring the ACS server and NADs. You must also think about the hosts themselves. Our …   Read More

  • In the previous editions of “Subnetting Shortcuts”, we solved various types of problems involving subnet masks. This time, we’ll look at some more complex cases, specifically those in which the subnet/host boundary lies within the second or third octets. But first, because our lives would be incomplete without it, here is the powers of two …   Read More

  • This time, we’ll use the shortcuts to solve some different types of problem. Instead of “find the mask”, this time the challenge is to “find the subnet”. Ready? Here’s the first problem: given a host address of 192.168.1.100 and a subnet mask of “/27”, determine the host’s subnet, the legal range of host addresses on …   Read More

  • In “Part 3”, we solved a subnet masking problem using shortcuts. This time, we’ll use the shortcuts to solve some additional problems. Here’s the first problem: given an address space of 172.16.1.0/24, divide the network...

  • My earlier post introduced the Cisco MeetingPlace solution that combines voice, video and web conferencing products that are housed within the customer’s private network, allowing for a lower cost of service and maximum security.Today we’ll go over the hardware platforms involved.   Read More

  • VLANs, as we discussed before, are used to create logical broadcast domains on switches. However this information needs to be synchronized between switches. Manual configuration can be tedious in a large scale network, so understanding...

  • In “Part 2”, we solved a subnet masking problem using binary. This time, we’ll look at some helpful shortcuts that can make solving such problems faster and easier for most people (and less error-prone, as...