How do we know when things go bad? In a previous PodSnack we talked about the functions of the Data Link Layer, one of which is to detect bit errors in a transmission. But how is that accomplished? How does the transmitter provide enough information to the receiver that it can make this assessment. The key is something called a Cyclic Redundancy Check (CRC) and, in today's PodSnack, Michel explains it to you.

You can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

We've talked a bit about security in some of our PodSnacks. Let's wander back to that area and spend a bit of time talking about encryption. Encryption is very important any time we are sending information that we want to keep private to places that are outside of our control. That would include across the Internet, out in the radio space using Wi-Fi or cellular technology, or even on tapes that we back up and store off our premises. In today's PodSnack, I'll explain the basic concept to you.

You can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

This past week, Trevor and I have been working with a customer to craft a new course to help their people better understand their own products and services, especially the newer ones. As we worked on the materials, I began to realize how many terms we have yet to add to our library of PodSnacks. Some of these may seem, at first glance, to be very basic concepts. But they have many nuances. One such term is long distance. Seems simple, right? But did you know there are actually at least four different types? In today's PodSnack, I'm going to define the terms and types a bit. Then, in subsequent PodSnacks, I plan to delve into some related issues.

As always, you can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

I seem to be in a groove of filling in missing pieces of matched sets. A few weeks ago, Paul walked you through the meaning of analog. But we never really discussed the word digital. So today, I'm going to take you through the concept.

You can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

Have you ever studied languages? If you have, you may have heard reference to the so-called "romance" or "Latin" languages. These are all of the languages that descend from ancient Latin, and include English, French, and Spanish. In languages, if you study the root language, you very quickly gain facility in understanding and learning the descendant languages. Much the same happens in the study of communication protocols, which are essentially languages. Today we're going to look at the Latin of Data Link Layer protocols: something called the High-level Data Link Control (HDLC) protocol. Unlike Latin, however, it has not faded from common use. Many devices (e.g., Cisco routers) still support the use of this protocol for certain kinds of interfaces. Listen in and I'll give you the basics.

As always, you can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

Some time ago, Mark gave you a run down of the concept of a virtual circuit. I suppose it's long past time we complete the matched set, so today, Paul will tell you about the other type of packet network, the datagram network.

You can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

We hear a lot about convergence, but the discussion is often focused on combining voice and data in a common network. Convergence is about more than the network, though. It's also about the applications. Today, we'll ask Paul to take us through a basic description of unified messaging (UM). UM is one of the critical drivers for convergence.

You can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

Our series on routing protocols is essentially complete, although we are likely to come back and fill in some technical details. We have some outstanding requests for information on MPLS and BGP. For now, however, let's go back to a few basics. In today's PodSnack, Michel and Trevor take you through a definition of Virtual Private Networks.

You can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

In another PodSnack we talked about the maximum signaling rate (also known as baud) of a communication channel. Today we're going to see if we can take the next step and talk about the maximum bit rate. To do that we have to talk a bit about noise, the signal-to-noise ratio (SNR), and Claude Shannon. Listen in and I'm tell you why it is that shortening a cable, or changing the medium, can have such dramatic effects on the speed of our communication.

As always, you can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.

Our series on routing protocols concludes as we explore a hybrid routing protocol from Cisco. Michel takes you through a description of the Enhanced Interior Gateway Routing Protocol.

You can listen to (or download) the PodSnack by clicking here, or you can use the Flash player below.

If you have an idea or request for a PodSnack topic, send it to podsnacks@hill.com! You can get a complete list of our PodSnacks here. You can register for our PodSnack series by RSS feed by adding this link to your podcast aggregator: http://feeds.feedburner.com/HillAssociates-LivingInAConnectedWorldPodsnacks.