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To flow or not to flow?

NetApp’s newest storage operating system, clustered Data ONTAP (cDOT), leverages a backend of Cisco Nexus switches for it’s cluster interconnect network.

When configuring the switch/cluster ports for use with cDOT, the best practice is to turn flow control off as per TR-4182. In fact, that happens to be the recommendation for normal data ports as well. Why is that? Before we get into that, let’s cover the basics…

What is flow control?

Flow control is a mechanism used to help manage the rate of data transfer between two devices. This is done to help prevent a source evice from overwhelming a destination device by sending more packets than the destination can handle. These scenarios can occur if a source device is faster than the destination device (CPU, RAM, NIC, etc). This can also happen if the source is intentionally trying to flood the destination via a malicious Denial of Service (DoS) attack.

Flow control can be enacted for send or receive packets, or both. It can be hardware or software based. It can occur at multiple layers of the OSI model

For a real world analogy to flow control, think of how dams work. A dam will be installed to control the flow of water on a river, usually to create lakes or reservoirs. Dams can be used to adjust the water flow to prevent flooding, depending on rainfall. Network flow control does pretty much the same thing – it prevents data floods. Read More »

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So You Want to be a Network Engineer. Here’s Where You Should Start!

First lets talk about what a Network Engineer is. According to The Free On-line Dictionary of Computing. Retrieved April 27, 2015, from website a Network Engineer is:

“A high-level LAN /WAN technician who plans, implements and supports network solutions between multiple platforms. A network engineer installs and maintains local area network hardware and software, and troubleshoots network usage and computer peripherals.”

Network Engineers can wear many different hats. I believe the more “Traditional” Network Engineers mainly work on devices such as Routers, Switches, Firewalls, Wireless Access Points and Controllers, Load Balancers, Intrusion Detection and Prevention Systems as well as some server maintenance involving virtualization and network management software. Next we should discuss the overview of the differences between Network Engineering and Administration. Keep in mind I am just talking from an industry general view/standpoint. Some companies may not differ between the 2 titles. Engineers and Admins tend to share a lot of responsibility when it comes to maintaining and troubleshooting a network. The dividing line seems to be in the design/installation area with the bulk of this work generally being done by the more “experienced” engineers. Admins usually fall under the NOC (Network Operations Center) which in large companies/agencies is usually staffed 24x7x365. I have also seen the difference broken down into tiers when it comes to troubleshooting escalation. Network Admins usually fall in the Tier 1-2 range with Engineers being considered Tier 3. Read More »

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SDN – A Cisco Champion’s perspective

Software defined networking (SDN for short) is going to be an important technology that will change the way we do networking. But what is SDN today and even more important, what is it going to be?

When you start reading about SDN as a network engineer, you ask yourself what your future job will look like. Will you still be a network engineer as we know you today, or a network developer, with a focus on scripting and programming your network? In my opinion, the reality will be somewhere in between. But no one can tell you today what impact SDN will have on your daily work tomorrow. Read More »

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4+1 Practices for Effective Lifelong IT Learning (Part 2)

Happy with how you go about learning, or wish you could learn more, learn more quickly, and even just do it? Today’s post continues what was begun in the previous post, namely a list of good practices to consider to improve how you go about learning throughout your IT career.

The previous post set up the issues, and made two broad suggestions:

  • Continuously learn more about learning and study, practice what you learn, and improve
  • Research and improve note-taking skills for each type of notes you take

Today’s post adds two more practices to the list, with a renewed request that you add your suggestions as well. Today, we’ll examine one type of short-term tactical goal setting with SMART goals, plus a much-neglected study activity: thinking about what you already studied.

3) Start Each Week w/ Achievable SMART Goals

Have you ever finished a week with this thought?

“I failed to make as much progress as I would have liked to make with what I’m learning right now.”

Many factors, both controllable and uncontrollable, affect whether we meet our goals. This next practice helps us achieve our short-term goals by setting and reviewing SMART learning goals weekly, every week.

WO-Cisco-2015-03-fig4 Read More »

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Is Your Network Cloud Ready?

Is your network cloud ready? We at NetCraftsmen, a Cisco Gold Partner, are hearing this question more often. Let’s discuss how to tell if your network is cloud ready, and how to get there if you’re not. Even if your organization already has a public cloud presence, I hope you’ll find some ideas in the following material.

Is Your Network Cloud Ready

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