August 05, 2015

XKCD Comics

August 04, 2015

My Etherealmind

5 Career Tips I Learned From John Chambers and Cisco

My work life has been closely tied to Cisco’s success over the last 15 years and "Uncle" John Chambers has been my constant companion in that journey. Now that he has moved on to Chairman of the Board it is time to talk career tips that I learned from the master.

The post 5 Career Tips I Learned From John Chambers and Cisco appeared first on EtherealMind.

by Greg Ferro at August 04, 2015 08:20 PM

The Networking Nerd

TECH.unplugged And Being Present


I wanted to let everyone know that I’m going to be taking part in an excellent event being put on by my friend Enrico Signoretti (@ESignoretti) this September. TECH.unplugged is a jam-packed day of presentations from people that cover storage, computing, and in my case networking. We’re getting together to share knowledge and discuss topics of great interest to the IT community. As excited as I am to be taking part, I also wanted to take a few moments to discuss why events like this are important to the technology community.


There’s no doubt that online events are becoming the standard for events in recent years. It’s much more likely to find an event that offers streaming video, virtual meeting rooms, and moderated discussions taking place in a web browser. The costs of travel and lodging are far higher than they were during the recession days of yore. Finding a meeting room that works with your schedule is even harder. It’s much easier to spin up a conference room in the cloud and have people dial in to hear what’s going on.

For factual information, such as teaching courses, this approach works rather well. That’s where the magic of pre-recording comes into play. Write once, read many. Delivering information like this cuts down on time spent with the logistics of organization and allows the viewer to watch on-demand. And quesitons that come up can be handled with FAQs or community discussion on a small scale. Again, this works best for the kinds of content that are not easily debated.

Present And Accounted For

What about content that isn’t as cut-and-dried? Hot topics that are going to have lots of questions or opinions? How do you handle an event where the bulk of the time is spent having a discussion with peers instead of delivering material?

Virtual solutions are great for multicasting. When everyone is watching one topic being presented and doing very little interacting everything works just fine. The system starts to break down when those people try to talk to one another. Do you use the general channel? Private messages? Have you been silenced by the organizer before you try to ask a question? What if you want to discuss a topic covered five minutes ago?

Nothing beats a face-to-face conversation for actual discussion. There’s an dynamic that can’t be matched when you get ten people in a room and give them a prompt to start talking about something. There is usually lively debate and sharing of viewpoints. Someone is going to share a personal experience or be the voice of reason. Still others will play the devil’s advocate or be a contrarian. Those are concepts that are hard to replicate when screen names take the place of a nametag.

Another important part of being present for events like this is meeting like-minded people and engaging them in real conversation. In the world of social media, we often form relationships with people in the industry without having actually met them. While that does make it easy to build a network of people in the community to talk to, it also doesn’t allow you to hear someone talk or engage them in a meaningful talk of more than 100 characters at a time or nested comments.

There’s something magical about having in-person discussions. It is a very different thing to defend your opinion when looking someone in the eyes versus behind a keyboard. Without instant access to search engines you need to know the evidence to support your opinion rather than relying on someone else to do it for you. When you prove your point in a real life meetup people remember being there.

Tom’s Take

Virtual meetings are great for some specific things. But you can’t beat the importance of being around people and talking about something. Being present for an event makes it have much more of an impact. I’ve heard from countless people telling me how Cisco Live feels so much different when you’re there because of the people you are around. There’s a reason why Tech Field Day is an in-person event. Because you can’t beat the magic of being around other like-minded people to discuss things.

Be sure to check out TECH.unplugged and see the list of speakers for the September event. And if you just happen to be in Amsterdam be sure to sign up (it’s free)! We want you there!

by networkingnerd at August 04, 2015 01:49 PM

Peter's CCIE Musings and Rants

Jabber Screenshare gotcha

Hey Guys

Super quick Gotcha for your Cisco Jabber, with Jabber for Mac OS X, if you want to do screenshare, you must escalate during a phone call, you can't do it just from a chat, you CAN do it just from a chat on IM.

by peter_revill ( at August 04, 2015 08:09 AM

Networking Now (Juniper Blog)

What’s Driving IPv6 Adoption? (An IPv6 Epiphany)

I have been giving IPv6 presentations for years now. It is always the same pitch; the same slides on why IPv6 is important; how governments are using it, and universities, and so on. I use the graph from Google[Google IPv6 Stats] below to illustrate the growth of IPv6.


IPv6 Epiphany - ipv6graph.jpg


Recently, someone in the audience pointed out that I need to update my slide. In two months, the share of IPv6 traffic on Google was up by 10%. But wait a second! IPv6 is arguably a quarter century old. It took almost that long to grow to about 1% of the Internet traffic. And now it is growing that much every month?


What’s going on? Who or what is driving the growth of IPv6 traffic?


There are approximately 10 billion Internet connected devices out there. We adapted quite well to running out of IPv4 addresses a long time ago by using NAT and private addresses spaces. It is unlikely that the “shortage” of IP addresses is the root cause.


Just eyeballing the statistics on the World IPv6 Launch website, it is not enterprises, not even governmental and educational institutions, but the service providers. Services providers, especially the mobile service providers are going through profound changes with smartphones and LTE. Some of the mobile service providers, when they put in a completely new infrastructure, such as VoLTE, elect to go all-IPv6. It makes perfect sense. It is much simpler to deploy IPv6 than use NAT, especially with IMS. But none of that would drive to growth shown above.


It is CVfCP


It turns out that content providers prefer IPv6. IPv6 gives them enhanced visibility of the client endpoint. Client Visibility for Content Providers drives the IPv6 adoption rate. (Bill Shelton, who explained all this to me, coined the term and the acronym, CVfCP.)


Most devices today come with dual-stack IP; a device has both an IPv4 and an IPv6 stack. It is up to an application to select which one to use. The past few years, web browsers implemented a functionality commonly call Happy Eyeballs, which was also standardized by the IETF.[rfc6555] Happy Eyeballs claims to improve user experience in a network of still coexisting IPv4 and IPv6 servers by making simultaneous IPv4 and IPv6 connection attempts. But curiously, upon availability of both, the client gives preference to IPv6. It is fascinating that while currently there is arguably little to no benefit for the end user, the owner of the eyeballs, the content providers, who also control the clients, are implementing measures with preference to IPv6.


So why would the content providers prefer IPv6 addresses? It just happens that the largest content providers are also some of the main providers of browsers. NAT obfuscates the identity of a client; the IP address is the IP address of the NAT device and both the IP address and the port number may change from connection to connection. The content providers built elaborate schemes to track the identity of the clients, e.g., HTTP cookies. With an IPv6 address there is no NAT. The IPv6 address does not change over time, it remains the same from connection to connection, application to application. Most clients default to Stateless Address Autoconfiguration (SLAAC)[rfc4862] which builds the IPv6 address from the local subnet and the IID. The IID, the lower 64 bits of the IPv6 address is generated from the EUI-64, essentially the MAC address assigned to the NIC, which includes the manufacturer’s ID. The IID is unique and remains the same regardless of the network the device is connected to.


Let’s see what we have here; an IPv6 address uniquely identifies an endpoint, it says something about the device, and it is constant regardless of time, location, network, and application. Who needs cookies?


IPv6 Epiphany - happy.jpg


Epiphany, a lovely word. I never had a chance, a reason to use it. Now I did, thanks to Bill Shelton, one of our greatest IPv6 advocates. You can find his blog on IPv6 here.


by skohalmi at August 04, 2015 03:56 AM

August 03, 2015

The Networking Nerd

The Score Is High. Who’s Holding On?


If you haven’t had the chance to read Jeff Fry’s treatise on why the CCIE written should be dropped, do it now. He raises some very valid points about relevancy and continuing education and how the written exam is approaching irrelvancy as a prerequisite for lab candidates. I’d like to approach another aspect of this whole puzzle, namely the growing need to get that extra edge to pass the cut score.

Cuts Like A Knife

Every standardized IT test has a cut score, or the minimum necessary score required to pass. There is a surprising amount of work that goes into calculating a cut score for a standardized test. Too low and you end up with unqualified candidates being certified. Too high and you have a certification level that no one can attain.

The average cut score for a given exam level tends to rise as time goes on. This has a lot to do with the increasing depth of potential candidates as well as the growing average of scores from those candidates. Raising the score with each revision of the test guarantees you have the best possible group representing that certification. It’s like having your entire group be members of the honor roll.

A high cut score ensures that unqualified personnel are washed out of the program quickly. If you take a test with a cut score of 800 and you score a 500, you quickly know that you need to study quite a bit more before you’re ready to attempt the exam again. You might even say to yourself that you don’t know the material in any kind of depth to continue your quest for certification.

What happens if you’re just below the cut score? If you miss the mark by one question or less? How much more studying can you do? What else do you need to know? Sure, you can look at the exam and realize that there are many, many more questions you can answer correctly to hit the right score. But what if the passing score is absurdly high?

Horseshoes and Hand Grenades

I believe the largest consumer of purloined test questions is not the candidate that is completely clueless about a subject. Instead, the largest market of these types of services is the professional that has either missed the mark by a small margin or is afraid they will not pass even after hours of exhaustive study.

Rising cut scores lead to panic during exams. Why was a 790 good enough last time but now I need an 850 to pass? It’s easy to start worrying that your final score may fall in between that gray area that will leave lacking on the latest attempt. What happens if you miss the mark with all of the knowlege that you have obtained?

Those are the kinds of outcomes that drive people to invest in “test aids”. The lure is very compelling. Given the choice between failing an exam that costs $400 or spending a quarter of that to have a peek at what might be on the test, what is stopping the average test taker besides morality? What if your job depended on passing that exam? Now that multi-hundred dollar exam becomes a multi-thousand dollar decision.

Now we’re not talking about a particular candidate’s desire to fleece a potential employer or customer about knowledge. We’re talking about good old fashioned fear. Fear of failure. Fear of embarassement. Fear of losing your livelyhood because of a test. And that fear is what drives people to break the rules to ensure success.

Cut Us Some Slack

The solution to this issue is complicated. How can you ensure the integrity of a testing program? Worse yet, how can you stem the rising tide of improper behavior when it comes to testing?

The first thing is to realize what drives this behavior. Should a test like the CCIE written have higher and higher cut scores to eliminate illicit behavior? Is that really the issue here? Or is it more about the rising cut score itself causing a feedback loop that drives the behavior?

Companies need to take a hard look at their testing programs to understand what is going on with candidates. Are people missing the mark widely? Or are they coming very close without passing? Are the passing scores in the 99th percentile? Or barely above the mark? Adjustments in the cut score should happen both up and down.

It’s easy to look at testing groups and say, “If you just stuided a bit harder, you’d hit this impossibly high mark.” It’s also very easy to look at scores and say, “We see that many of you are missing the mark by less than ten points. Let’s lower that and see how things go from here.”

Certification programs are very worried about diluting the pool of certified candidates. But is having more members of the group with scores within a question or two of passing preferable to having a group with absurdly high passing scores thanks to outside help?

Tom’s Take

I’ve taken exams with a 100% cut score. It’s infuriating to think that even a single wrong answer could cost you an entire exam. It’s even worse if you are financing the cost of your exam on your own. Fear of missing that mark can drive people to do lots of crazy things.

I’m not going to say that companies like Cisco need to lower the cut scores of exams to unrealistically low levels. That would cheapen the certifications that people have already earned. What needs to happen is that Cisco and other certification bodies need to learn what they are trying to accomplish with their programs and adjust all the parameters of the tests to accomplish those goals.

Perhaps raising the cut scores to more than 900 points isn’t the answer. Maybe instead more complex questions or more hands-on simulations are required to better test the knowledge of the candidates. These are better solutions that take time and research. They aren’t the false panacea of raising the passing score. The rising tide can’t be fixed by making the buoys float just a little higher.


by networkingnerd at August 03, 2015 07:55 PM

XKCD Comics

July 31, 2015

XKCD Comics

July 30, 2015


Is SD-WAN Simply WAN Optimization Evolved? Not Exactly.

Consumers evaluating SD-WAN shouldn't think of it as a WAN optimization replacement, at least not exactly. These are different technologies, although it might be fair to think of SD-WAN as the successor to WAN optimization. SD-WAN and WAN optimization are compatible technologies, but not interdependent technologies.

by Ethan Banks at July 30, 2015 10:45 PM

Scalability Is A Matter Of Context

Scale is a relative term. While every technology needs to scale to some point to be useful to IT practitioners, not every technology needs to scale infinitely. Every technology has a context in which it is viable — where it proves to be the best choice. But in another context, the opposite technology might rise to the surface as more appropriate. Don't be religious about such a decision. Know your business need well, research the technology thoroughly, plan for the future, and choose wisely. Don't pick a tool that solves someone else's problem.

by Ethan Banks at July 30, 2015 09:03 PM

July 29, 2015

XKCD Comics

July 28, 2015

Peter's CCIE Musings and Rants

July 27, 2015

XKCD Comics