Russ

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Reaction: DNS versus anycast

This post raises an obvious question: are techniques using DNS to “steer” traffic (such as IP geolocation) sufficient, or do you need to consider using anycast as LinkedIn did? The short answer is that DNS steering works well and is only getting better. via circleid

Matt’s article is well worth reading, but once you’re finished reading it —

It’s well worth remembering when dealing with different load balancing solutions (like most other things in life) that the right answer is, “it depends.” In this case, do you need TCP anycast, or can you use DNS based load sharing? It depends not only on how effective each one is, but also what sort of application you’re working with. Many apps designed for smart phones don’t use DNS at all, so some form of anycast or appliance based solution are all you have. Between these two, anycast is often just as viable a solution if your network is designed to handle it correctly.

In the end, all three solutions — anycast, DNS, and appliance based — are viable options. Which one you should choose just all depends.

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Review: The Art of the Humble Inquiry

humble-inquiryHumble Inquiry: The Gentle Art of Asking Instead of Telling
Edgar H Schein

Edgar Schein says we have a cultural issue. We like to tell people what we think, rather than asking them what they’re trying to tell us. Overall, especially in the world of information technology, I tend to agree. To counter this problem, he suggests that we perfect the art of the humble inquiry — redirecting our thinking from the immediate solution that comes to mind, or even from the question that was asked, and trying to get to the what the person we’re talking to is actually asking.

He gives numerous examples throughout the book; perhaps my favorite is of the person who asked stopped their car while he was doing yard work to ask directions to a particular street. Rather than answering, he asked where they were trying to get to. They were, in fact, off course for their original plan, but he directed them down a different path that got them there faster than if they’d turned around and found their way back to that original path. This is a perfect example of asking returning a specific question with a larger question — an authentic Continue reading

QOTW: The Occupation of the Wise

Thus the wise man, at all times and on every road, carries a mind ripe for acquisitions that ordinary folk neglect. The humblest occupation is for him a continuation of the loftiest; his formal calls are fortunate chances of investigation; his walks are voyages of discovery, what he hears and his silent answers are a dialogue that truth carries on with herself within him.
Sertillanges, The Intellectual Life

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The Odd Hours Solution

For many years, when I worked out in the center of the triangle of runways and taxiways, I would get up at around 4, swim a mile in the indoor poor (36 laps), shower, grab breakfast, run by base weather just to check the bigger pieces of equipment out (mostly the RADAR system), and then I’d head out to the shop. We could mostly only get downtime on the airfield equipment (particularly the VOR, TACAN, and glideslopes) in the early morning hours — unless, of course, there was a war on. Then we couldn’t get downtime at all. By 2:30 I was done with my work day, and I headed home to get whatever else done.

When I left the USAF, after being trapped in some 9–5 jobs, I joined the cisco TAC. Our shift started at 8 or 8:30, when we took over the 1–800 number from Brussels, and our shift lasted until around 2 in the afternoon (it varied over time, as the caseloads and TACs were moved around). Freed from 9–5, I started getting to work at around 5:30 again. I could spend the first two or three hours following up on cases (did you know that Continue reading

QOTW: Obsession with Knowledge

Like Gollum’s self-destructive obsession with the ring in Tolkien’s novels, when we see knowledge as something to possess, not only do we miss out on the fulfillment of seeing that knowledge positively influence the lives of those around us, but we miss out on the rich personal growth that results from participation in a free give and take of truth.
Philip Dow, Virtuous Minds

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IT/IT: Distributed OpenFlow

According to ECI, it’s a naïve view to have a single controller control large-scale networks in a reactive mode. Such a global view doesn’t scale, ECI claims. It means the first frame of each new flow is sent to the controller, where an SDN app decides on the desired behavior, derives the required network configurations and then uses the SDN controller to configure all the relevant switches. via sdxcentral

If I were a bit more snarky, I’d be tempted to say something like, “well, if you add a small hello protocol to each of the applets to monitor neighbor reachability, and a small protocol that can exchange local reachability information, and then perhaps a local algorithm to determine which path is the shortest, you can reinvent IS-IS.” But I’m not that snarky, of course…

I have come to believe that at least half of what we invent in the networking world is simply a product of not spending the time nor effort to study what’s already been invented, or the perception that what’s already been invented is “too complex,” and hence not stuff anyone wants to spend time learning nor understanding. A full three quarters of what remains is Continue reading