KIClet: IOS “network” Command Cheating
I have always used the “network 0.0.0.0 0.0.0.0” statement to describe “all interfaces” when configuring a routing protocol like EIGRP. I know that it’s not correct, but I never stopped to wonder why my bad habit still worked. Then, I found this good article by @jdsilva explains this is IOS just assuming you had a “brain fart” and meant to type the proper “network 0.0.0.0 255.255.255.255” I’m studying for the CCIE and it can be really good to identify these bad habits that, while in real life may not be too bad, especially this kind, where the result is the same, but on exams can mean the difference between failure and success.You have a new manager – now what do you do?
We’ve all been there – a recent re-org or maybe your boss gets promoted or your boss leaves and you end up with a new manager. As I have mentored people over the years, I’d say that the most common reaction is “Crud! I have to start over.” But once you get past that moment […]
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The post You have a new manager – now what do you do? appeared first on Packet Pushers Podcast and was written by Michael Bushong.
Traditional AQM is not enough!
Note: Updated October 24, 2013, to fix some editorial nits, and to clarify the intended point that it is the combination of a working mark/drop algorithm with flow scheduling that is the “killer” innovation, rather than the specifics of today’s fq_codel algorithm.
Latency (called “lag” by gamers), once incurred, cannot be undone, as best first explained by Stuart Cheshire in his rant: “It’s the latency, Stupid.” and more formally in “Latency and the Quest for Interactivity,” and noted recently by Stuart’s 12 year old daughter, who sent Stuart a link to one of the myriad “Lag Kills” tee shirts, coffee bugs, and other items popular among gamers.
Out of the mouth of babes…
Any unnecessary latency is too much latency.
Many networking engineers and researchers express the opinion that 100 milliseconds latency is “good enough”. If the Internet’s worst latency (under load) was 100ms, indeed, we’d be much better off than we are today (and would have space warp technology as well!). But the speed of light and human factors research easily demonstrate this opinion is badly flawed.
Many have understood bufferbloat to be a problem that primarily occurs when a saturating “ Continue reading
Vendor mandated certs only degrade integrity
I dont doubt that vendors have a tight line to walk when it comes maintaining their brand integrity. To build up a skill set in the market the certification teams put in many weeks developing a program that is relevant, useful and achieves the goals required. Followed by countless hours reviewing each of the certifications regularly to ensure integrity. There is the added benefit that these certifications build of community of loyal followers – The Cisco and VMWare certification programs are evidence to this.
I personally have been involved in the development, technical review, and exam rewrite process and I can attest to the effort that the certifications teams go to to ensure the validity and integrity of their offerings. Weeding out sources of brain dumps and NDA violations and other activities that threaten this integrity work becomes an on going commitment that requires many hours of dedication.
On the other side of the line is the requirement to have the partners representing the vendor to maintain a level of skills and customer satisfaction. This ensures that when the brand is represented in the market that it will be delivered by the most skilled people capable of delivering the Continue reading
The Illusion of Perfection
I spend a lot of time commuting. During that commute, I listen to technical podcasts and lots of different leadership and career oriented audio books. One of the topics that experts seem to have differing opinions on is defining what is good enough. I’ve heard many refer to Nike’s ad campaign, Just Do It, and […]
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The post The Illusion of Perfection appeared first on Packet Pushers Podcast and was written by Paul Stewart.
Snowden Media Douchebaggery
Recently the New York Times posted an article stating that while Edward Snowden was at the NSA, he learned to be a hacker by taking a CEH course and getting the certification. But the certification, listed on a résumé that Mr. Snowden later prepared, would also have given him some of the skills he needed […]
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The post Snowden Media Douchebaggery appeared first on Packet Pushers Podcast and was written by Mrs. Y.
Cisco ASA Virtualization with Mixed-Mode Security Contexts
The Cisco ASA firewall has supported multiple security contexts since version 7 was released in 2005. This feature allows you to configure multiple independent logical firewalls in the same ASA hardware. When version 8.5(1) released in July 2011, support was added for mixed mode firewalls in which both routed and transparent contexts can reside on […]
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The post Cisco ASA Virtualization with Mixed-Mode Security Contexts appeared first on Packet Pushers Podcast and was written by Eyvonne Sharp.
The Smartest Guy in the Room
There is one thing that anybody who has been in a room with me longer than 5 minutes can tell you – I am not a smart guy! I have lots of smart friends. I am not one of them. Sometimes I feel like I’ve done more stupid things, more often than I would like to admit, and its only that I have been stupid enough often enough that I have eventually learned “dont do that!“.
A couple of things have happened over the past few weeks that made me think about “The Smartest Guy in the Room”, and I thought I would share a few incomplete thoughts on the matter.
As a Consultant
Back on June 18, Matthew Norwood (who I would nominate for the award of “Nicest man in Network Blogging and Puppeteering”) wrote this blog post about consulting. In this post he talks about how as a consultant sometimes you have to accept that you are not the smartest guy in the room. At first this may seem odd, especially because usually our customers are paying us lots of money because we are experts. Funnily enough, on consulting engagements my job is more “I Continue reading
Show 152 – Nexus Announcements from Cisco Live 2013 with Ron Fuller – Sponsored
Ethan Banks and Greg Ferro are joined by Brent Salisbury for a discussion with Cisco’s Nexus-geek-at-large Ron Fuller about a whole lot of things happening in the Cisco data center product line in this sponsored edition of the Packet Pushers Podcast. First up, we review the announcement from the previous Cisco Live (London 2013) about […]
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The post Show 152 – Nexus Announcements from Cisco Live 2013 with Ron Fuller – Sponsored appeared first on Packet Pushers Podcast and was written by Ethan Banks.
How to Prepare for CCDE Practical Exam
I was a bit harsh when I wrote: you have to be CCIE to pass CCDE. Couple of friends of mine, who are not CCIEs, came to me after reading that post and said I had demolished their hope to pass the exam.I won't lie. It's easier to become CCDE if you have already had a CCIE. But fear not, there is still chance for non-CCIE to pass CCDE exam as well. And several guys who are not CCIE but able to put their name in this Hall of Fame is the proof.
The next CCDE practical exam date is on August 27. So there is still time for both groups of CCIE and non-CCIE to pass it, and here is another version of "how to prepare for CCDE exam" that may help to do so:
1. You still need a good reason to do it
You need a good reason as your main motivation to keep continue pursuing this certification, after you fail the exam. Or after you fail the exam several times.
So find your reason.
2. You still need the experience
You can't skip experience. I'm not kidding.
From CCDE Techtorial it says "CCDE Practical is Continue reading
Healthy Paranoia Show 14: Digital Forensics and Incident Response with Andrew Case
Get ready for another nerdilicious episode of Healthy Paranoia featuring Andrew Case, digital forensics researcher and a core developer for the Volatility Framework. Liam Randall joins Mrs. Y. as they discuss topics such as: The difference between forensics and incident response. Malware analysis vs. reverse engineering. Why you should treat a compromised system like a […]
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The post Healthy Paranoia Show 14: Digital Forensics and Incident Response with Andrew Case appeared first on Packet Pushers Podcast and was written by Mrs. Y.
Control Plan and Data Plan – Answer provided by Keith Barker
I came across this great answer to a question from Keith Barker and felt it needed to be shared. Great analogy Keith.
PQ Show 28 – UCS Director Overview – Sponsored
In this show recorded in a small little room with a great big fan (which we were mostly able to edit out) in the “Meet the Expert” lounge at Cisco Live 2013 in Orlando, Packet Pushers Greg Ferro and Ethan Banks discuss Cisco’s UCS Director product (formerly Cloupia) with folks from the UCS Director team. […]
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The post PQ Show 28 – UCS Director Overview – Sponsored appeared first on Packet Pushers Podcast and was written by Ethan Banks.
Air as a service
Have you ever wondered about air? We all share the same air. We know it's vitally important to us. If we safeguard it we all benefit and if we pollute it we all suffer. But we don't want to have to think about it every time we take a breath. That's the beauty of air. Elegantly simple and always there for you.Imagine air as a service (AaaS), one where you need to specify the volume of air, the quality of the air, etc before you could have some to breathe. As much as some folk might be delighted in the possibility to capitalize on that, it would not be the right consumption model for such a fundamental resource. If we had to spend time and resources worrying about the air we breathe we'd have less time and resources to do other things like make dinner.
Why does air as it is work so well for us? I think it's for these reasons, (1) there is enough of it to go around and (2) reasonable people (the majority) take measures to ensure that the air supply is not jeopardized.
Network bandwidth and transport should be more like how we want Continue reading
Optimizing and Protecting Spanning Tree
Optimizing STP
Left to defaults, 802.1d (plain old STP) can take a very long time to converge. For example, when a root switch fails, a switch must wait Maxage (20 seconds) before convergence can even begin. Then, the newly forwarding ports must wait 2 x Forward Delay (15 seconds) to transition through the listening and learning states before they can begin to actually start forwarding. This is a total of 50 seconds - a noticeable network hit.
Enhancements have been added over time to address this, such as PortFast, UplinkFast, and BackboneFast.
PortFast
This Cisco-proprietary feature allows a port to immediately transition to forwarding state once it is physically up (powered on and plugged in). It does this by skipping the listening and learning states. This should only be enabled on access ports. If a switch is connected to a port with PortFast enabled, loops may occur. For this reason, it is a good idea to enable Bridge Protocol Data Unit (BPDU) Guard and Root Guard when using PortFast.UplinkFast
UplinkFast improves convergence by providing alternate root ports (RPs) for immediate transition in case of a failure of the current RP. Continue reading
PQ Show 27 – Cisco XNC Controller – First Look – Sponsored
Cisco eXtensible Network Controller (XNC) can provide greater business agility, through a cost-effective, scalable, Software-Defined Network (SDN)-based approach to traffic monitoring. What is the XNC? What’s it for? Comparing XNC Controller to OpenDaylight. What’s the same? What’s a value-add? What are the northbound capabilities of XNC? Southbound? Let’s give some examples of what we can […]
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The post PQ Show 27 – Cisco XNC Controller – First Look – Sponsored appeared first on Packet Pushers Podcast and was written by Greg Ferro.
Preparing For Technology Trends
I spent most of last week at Cisco Live. This is a large and well-known technology conference. While attending the keynote sessions, I kept wondering how many people take the time to future-proof themselves. I know we all have a lot of work just educating ourselves on the technology of today. However, I have to […]
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The post Preparing For Technology Trends appeared first on Packet Pushers Podcast and was written by Paul Stewart.
An Introduction to the Nexus 7700
We're halfway through 2013 and we have our second new member of the Nexus family of switches for the year: the Nexus 7700. Here are the highlights:
- Modular, chassis-based system
- 18 slot (16 IO modules) and 10 slot (8 IO modules)
- True front-to-back airflow
- New fabric modules
- (6) fabric modules (maximum) per chassis
- 220G per slot per fabric module
- 1.32Tbps per IO module slot
- Supports F2E and newly announced F3 IO modules
Best Practices for Benchmarking CoDel and FQ CoDel (and almost anything else!)
The bufferbloat project has had trouble getting consistent repeatable results from 
other experimenters, due to a variety of factors. This Wiki page at bufferbloat.net attempts to identify the most common omissions and mistakes. There be land mines here. Your data will be garbage if you don’t avoid them!
Note that most of these are traps for people doing network research in general, not just bufferbloat research.
