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Category Archives for "Networking"

Secrets Behind A10 Health Monitors

Whether you use A10, f5 or some other load balancer, you’re probably used to the idea of health monitors, or “health checks”. The load balancer periodically performs some kind of connectivity test to the servers that are used to service … Continue reading →

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Outcome bias and the psychology that prevents sustained success

In psychology, there is a phenomenon called Outcome Bias, which basically means that we tend to judge the efficacy of a decision based primarily on how things turn out. After a decision is made, we rarely examine the conditions that existed at the time of the decision, choosing instead to evaluate performance based solely (or mostly) on whether the end result was positive or not.

But what happens as luck plays a role in outcomes? Did we actually make the best decision? Or was the result really a product of conditions outside of our control?

Understanding Outcome Bias

A relatively strong example of Outcome Bias can be found in the gambling world. Take poker, for instance. Many players will overplay the cards they are dealt. Imagine that you have four cards to a straight. There are two remaining cards to play. You might make bets that are statistically weak, but if the card you were looking for shows up, you will evaluate your own performance as strong for the hand. After all, you did win, right?

The challenge with Outcome Bias is that the fortuitous turn of events leads you play other hands in a similar way. Despite the fact Continue reading

First Impressions of the OpenDaylight Helium Release

First Impressions of the OpenDaylight Helium Release

by Hariharan Ananthakrishnan, Distinguished Engineer - October 21, 2014

OpenDaylight introduced Helium last month, which is a major upgrade to its open source SDN controller. Here’s my take on its features, shortcomings and strengths from an engineering perspective. 

Helium is the second software release from the OpenDaylight project and includes the following notable enhancements and new features: 

  1. Support for the Apache Karaf container to allow network operators to customize installation using only the features they want
  2. A new user interface, dlux (the OpenDayLight User eXperience) for client-side MVW (Model View Whatever)
  3. Group Base Policy for an application-centric way of expressing policy
  4. Accounting, authorization and authentication for enhanced security
  5. The BGPCEP project now supports provisioning segment routing through PCEP 

With Helium there are no base, virtualization or service provider editions. Instead, bundles are supported through karaf features. Unlike the first (Hydrogen) release, Helium is targeted towards production environments. 

Out of the Box Experience 

After downloading the pre-built zip file, it is straightforward to run the karaf container with the ‘bin/karaf’ script. The ‘help’ command in the console provides a list of karaf commands Continue reading

Confusing Times in Networking and Cognition Jumps


I’ve been researching four different and distinct types of networking in the last few weeks. I’m finding that the cognition required to jump between technologies is making my head hurt. Here is a summary of four technology areas that interest me this week. Optical Networking As part of research project I have been getting deep […]

The post Confusing Times in Networking and Cognition Jumps appeared first on EtherealMind.

Announcement: The Hot Aisle Newsletter

I’ve launched a newsletter called The Hot Aisle. Why might you care? The Hot Aisle is a personal look at my real life IT engineering projects, thoughts about the networking industry I won’t publish anywhere else, my growingly contrarian views on social media, good stuff I’ve read, and comments from fellow Hot Aisle readers. The content is […]

SDN Market Sizing Redux

In April 2013, Plexxi teamed up with SDNCentral to take a look at how the SDN market might emerge. The original post along with supporting info graphic and written analysis can be found here. At a high level, the major takeaway was that we predicted that between 30 and 40 percent of the networking market would be influenced by SDN by 2018. At the time, this was BY FAR the most aggressive take on SDN. IDC had been projecting a little more than $3B by 2018, which would put their estimates somewhere around 5% of the overall networking spend.

So 18 months later, how do I feel about the analysis?

SDN spend is largely substitutive

In the original analysis, I made the point that SDN spend is not likely to be net-new dollars coming into the networking industry but rather a shift in dollars from traditional networking equipment to SDN-enabled equipment.

How’d I do? I’d say that this was spot on. Of course, this was the easiest of the predictions at the time. It is rare that dollars are created; they are usually shifted from somewhere else. Here, all I was really predicting was that the somewhere else was other Continue reading

Openstack distribution

In the last few months, following were some acquisitions that happened: Cisco acquiring Metacloud, EMC acquiring Cloudscaling, HP acquiring Eucalyptus. Metacloud and Cloudscaling have Openstack based distributions, Eucalyptus has a cloud OS similar to Openstack. This set of acquisitions prompted me to look little closely at Openstack distributions and following blog is a result of this. … Continue reading Openstack distribution →

Response: http2 explained


Been researching HTTP2 protocol on the basis that is will, more or less, be the dominant protocol on the Internet and everywhere else. Aside from the sense of excitement I get from looking at solving old problems, HTTP2 is a huge change for networking and this site has the best explanation I’ve found so far. Check […]

The post Response: http2 explained appeared first on EtherealMind.

Using Ping Sweep to Find MTU Ceiling

Earlier this week I had breakfast with a very interesting group. One of those present had an extensive history with Cisco systems. We talked about his tenure and several of the projects that he had been involved in. For some reason, one that caught my attention was the sweep option that we find in the extended Ping utility. Although it is hard to believe, there was a point in time that this gem didn’t exist.

I’ve written a few articles about the challenges of path MTU discovery and the issues that arise when it misbehaves. Today’s article looks specifically at using a ping sweep and how it can be used to quickly identifying the path MTU ceiling. The topology used for testing is simple and shown below. Notice that the two top routers are connected by a link with a lowered MTU (1492).

Ping Sweep MTU Discovery

Let’s step through the process that an administrator might go through when a networked application isn’t working correctly. He or she would likely determine the endpoints and confirm reachability. For this example, I am testing a connection between 192.168.1.1 and 192.168.4.4. The ping command is the tool of choice for confirming reachability.

Basic Continue reading

Storage Primer

Storage is a very critical component in the current IT domain. Choosing the right Storage platform and software is a critical part of a good Data center whether it is internal or external cloud. Even though I understood some Storage basics, I never ventured deep to understand the different storage technologies available. I tried to … Continue reading Storage Primer →

Disappointed With Check Point

I have recently started working with Check Point products again, after a 5-year break. This has given me a different perspective on how they are progressing. It has been disappointing to see that they’re still suffering from some of the same old bugs. Some of the core functionality is now showing its age, and is no longer appropriate for modern networks.

When you’re using a product or technology on a regular basis, it can be hard to accurately gauge progress. Maybe it feels like there are only incremental changes, with nothing major happening. But then you come across a 5-year old system, and you realise just how far we’ve come. If you don’t think iOS is changing much, find some videos of the first iPhones.

The opposite is when it feels like there are many regular enhancements…but when you step back you see that core product issues are not dealt with. It can be hard to see this when you’re working at the coal-face. You need to step away, work with other products and systems, then return.

That’s what I’ve done with Check Point recently. Through much of the 2000s, I did a huge amount of work with Check Point firewalls. Continue reading

Plexxi Pulse – This Week at Strata + Hadoop World

This week we joined thousands of thought leaders, analysts, vendors and end-users at the O’Reilly Strata + Hadoop World in New York. This event brings together the business and science of Big Data, allowing attendees to learn about emerging technologies through case studies and guest speakers. It’s been a busy week featuring excellent speakers from all over, including The New York Times and Cloudera. While we’re veterans of other industry events such as Interop and VMworld, we’re newbies here, so it’s exciting to experience this all for the first time. Judging by how things have gone so far, you can bet we’ll be back next year for more.

In this week’s PlexxiTube video of the week, Dan Backman highlights how Plexxi integrates with VMware.

Below are our best reads of the week – enjoy!

Data Center SDN growing 65% this year

In a recent article in Network World, Jim Duffy highlights the massive growth within the datacenter market – evidenced by a 65 percent growth in 2014 as reported by the Dell’Oro Group. Personally, I think it will be interesting to see if SDN survives as a separate feature out of the larger networking market. If the datacenter Continue reading

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