Cisco on The IT Hollow

Discovery Protocols

Tue, 28 May 2013 14:40:33 +0000

If you find yourself in an unfamiliar network and want to understand how the networks are connected, it would certainly be nice to be able to tell what is connected to each other. Luckily there are a couple of protocols that are responsible for just that.

Cisco Discovery Protocol (CDP)

As you can probably guess from the name, the Cisco Discovery Protocol is a proprietary protocol from Cisco Systems.

NAT vs PAT

Tue, 05 Mar 2013 14:12:16 +0000

I often hear Port Address Translation (PAT)referred to as Network Address Translation (NAT). Its a pretty common to hear this and is really not a big deal because the two are similar and I know what is meant. But to clear things up I decided to put together a quick post.

Network Address Translation

NAT is the process of “translating” an IP Address in a router or firewall. This is most commonly done to present a private IP Address into a Public IP Address that is accessible on the Internet. For instance, you may want to have your E-mail server have a public address so that it can route mail.

Virtual Simulators

Tue, 19 Feb 2013 14:02:16 +0000

If you’re an engineer and you’re trying to get more experience with a variety of different storage devices, you might find yourself in a bit of a pickle. Most customers settle one one or two storage vendors and that’s it. So if you work for one of these companies you can learn EMC or Netapp, etc. I highly doubt your company would be interested in purchases a few different types of storage devices so that you can learn them as they are quite expensive.

A Quick Thought on VXLANs

Mon, 03 Sep 2012 11:00:48 +0000

After attending VMworld this year, I decided I needed to try to understand VXLANs a little better. Based off of the basic concept that it stretches a layer two broadcast domain over layer three networks, I was worried that I knew how this was accomplished.

What is VXLAN?

VXLAN stands for Virtual Extensible LAN and is a fairly new method of making the datacenter network elastic. Suppose for example that you want to be able to move your virtual machines from your own server room to a co-location and then to a public cloud depending on what the load was on your environment. In order to do this without causing downtime, you’d need a way for your layer two ethernet frames to continue getting from your clients to your servers even, if a router is in that path.