About a month ago I worked on an old CatOS switch. Working on this switch reminded me about some of the differences between CatOS and IOS. One of the big differences is how a Layer 3 routed interface is configured between the two OS versions. On a Catalyst running IOS, it is almost identical as […]
The post Cisco Internal VLAN Usage appeared first on Packet Pushers Podcast and was written by Charles Galler.
Recently, we met with a friend who has done an amazing job of understanding the lifecycle management of virtual machines (VMs). As the CTO of a very large cloud provider, he explained in deep detail how he took advantage of Moore’s Law and doubled the amount of VMs in each rack each year, while maintaining or shrinking the cost per rack. As a result, he has doubled the amount of earning potential in each data center while driving cost down, even as his staff is ripping out servers long before their traditional three- to four-year lifecycle and purchasing new ones. He is buying servers at a 3-to-1 ratio over a three-year period when compared with a typical server lifecycle, yet his cost to operate the data center is going down and his productivity is going up by 2x every year. Amazing!
While we enjoyed learning of his success, when we hear these stories, we think “Could this have the same type of impact somewhere in the network?” It got us to ask why customers traditionally hang on to their top-of-rack switches for four or five years and sometimes longer.
What is different about the network versus servers?
Obviously, Continue reading
Original content from Roger's CCIE Blog Tracking the journey towards getting the ultimate Cisco Certification. The Routing & Switching Lab Exam
If you have arrived on this page then I would assume you know what a network engineer is and would like to find out how to become a network engineer? If you are not sure what a network engineer is or does then the picture below explains it very well Picture courtesy of http://perceptionvsfact.com/ A […]
Post taken from CCIE Blog
Original post How to become a network engineer
In this post I share the slides, audio recording, and short outline of a presentation I gave at the Melbourne VMUG conference (Feb 2014) called “Three reasons why Networking is a pain in the IaaS, and how to fix it”.
As network technologists we know that when the compute architecture changes, the network architecture changes with it. Consider the precedent. The transition from mainframe to rack servers brought about Ethernet and top-of-rack switches. Blade servers introduced the blade switch and a cable-less network. And of course the virtual server necessitating the software virtual switch and a hardware-less network. At each iteration, we observe the architecture change occurring at the edge, directly adjacent to compute.
We can look at this superficially and say, “yes, the network architecture changed”. However if you think about it, the catalyzing change in each shift was the operational model, with intent to increase agility and reduce costs. The architecture change was consequential. Without compute, there is no reason for a network. Networking, both as a profession and technology, exists as a necessary service layer for computing. Without a network, computing is practically useless. As such, the capabilities of the network will either enable or impede Continue reading
In this post I share the slides, audio recording, and short outline of a presentation I gave at the Melbourne VMUG conference (Feb 2014) called “Three reasons why Networking is a pain in the IaaS, and how to fix it”.
As network technologists we know that when the compute architecture changes, the network architecture changes with it. Consider the precedent. The transition from mainframe to rack servers brought about Ethernet and top-of-rack switches. Blade servers introduced the blade switch and a cable-less network. And of course the virtual server necessitating the software virtual switch and a hardware-less network. At each iteration, we observe the architecture change occurring at the edge, directly adjacent to compute.
We can look at this superficially and say, “yes, the network architecture changed”. However if you think about it, the catalyzing change in each shift was the operational model, with intent to increase agility and reduce costs. The architecture change was consequential. Without compute, there is no reason for a network. Networking, both as a profession and technology, exists as a necessary service layer for computing. Without a network, computing is practically useless. As such, the capabilities of the network will either enable or impede Continue reading
In this post I share the slides, audio recording, and short outline of a presentation I gave at the Melbourne VMUG conference (Feb 2014) called “Three reasons why Networking is a pain in the IaaS, and how to fix it”.
As network technologists we know that when the compute architecture changes, the network architecture changes with it. Consider the precedent. The transition from mainframe to rack servers brought about Ethernet and top-of-rack switches. Blade servers introduced the blade switch and a cable-less network. And of course the virtual server necessitating the software virtual switch and a hardware-less network. At each iteration, we observe the architecture change occurring at the edge, directly adjacent to compute.
We can look at this superficially and say, “yes, the network architecture changed”. However if you think about it, the catalyzing change in each shift was the operational model, with intent to increase agility and reduce costs. The architecture change was consequential. Without compute, there is no reason for a network. Networking, both as a profession and technology, exists as a necessary service layer for computing. Without a network, computing is practically useless. As such, the capabilities of the network will either enable or impede Continue reading
Around six years ago, I decided to start a website called packetlife.net. Maybe you've heard of it. Most people turn to a purpose-built content management system like Wordpress or Drupal for such an endeavor, but I needed greater flexibility to achieve some of the projects I had in mind. This meant I needed to learn a programming language and write a good amount of the site's logic myself.
I already had some experience dabbling in PHP, but wasn't thrilled with it. I figured if I was going to learn a new language, it should be useful as a general purpose language and not just for building a web site. After a bit of research and deliberation, I chose Python (and the Django web framework).
The purpose of this post is to convince networkers with little to no experience writing code to learn Python. In the past I've encouraged fellow networkers to pick up any programming language, as it's more important to think like a programmer than it is to gain proficiency in a particular language. However, I've realized that many people get stuck on which language they want to learn, lose motivation, and end up not growing proficient Continue reading
This post represents the solution and explanation for quiz-21. It is a very long post describing Pre-bestpath community, Point of Insertion, offset list and other networking hacks employed to tackle a less common problem. Make yourself a coffee and start reading...
While at Networking Field Day 7, we got a small preview of a new switch Dell Networking has just announced, the Z9500. At some point I’ll have another post coming discussing more of Dell’s presentation at NFD7, but I wanted to briefly talk about this new product and what it brings to the table for Dell.
Dell Z9500
In a past post, we’ve discussed microloops in link state protocols. If we examine a small ring topology (if you come to my Interop talk, you’ll discover that ring topologies are the heart of network convergence), we can see where and how a microloop forms. If the link between A and B fails, A and […]
Putting the Application in SDN
by Steve Harriman, VP of Marketing - March 25, 2014
We would like to highlight a couple of recent articles about SDN that reflect Packet Design’s perspective on the technology. Arthur Cole wrote in Enterprise Networking Planet about “SDN in the Enterprise: It’s the Applications, Stupid.” He rightly asserts that the value of SDN isn’t in the architecture itself, but in the applications that the environment supports. It is understandable that during the genesis of a technology, the majority of effort is spent in making it work, but we should not lose site of the fact that optimal application performance is the key to deploying SDN more broadly. And we as an industry are not nearly ready to effectively manage applications across software-defined networks.
In fact, Cole cites an article written by our own CTO Cengiz Alaettinoglu in Data Center Knowledge about how traditional, manual management methods are inadequate in a programmable, automated network environment. We need to automate network management best practices and processes to give human operators the visibility and control needed to adequately manage SDN applications in the data center and across the WAN. Continue reading
