Are You a Fuddy Duddy?
This recent article from IEEE Spectrum discusses our impression that as we age, we lose the ability to learn quickly — fluid intelligence, as it’s called. An accompanying chart shows this in some degree through the skill of chess players across a range of ages. There’s something suspicious about this chart, though, and it’s pairing […]
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The post Are You a Fuddy Duddy? appeared first on Packet Pushers Podcast and was written by Russ White.
What is Jitter in Networking?
How does the internet work - We know what is networking
Simply said, time difference in packet inter-arrival time to their destination can be called jitter. Jitter is specific issue that normally exists in packet networks and this phenomenon is usually not causing any communication problems. TCP/IP is responsible for dealing with the jitter impact on communication. On the other hand, in VoIP network environment, or better […]
Machine Fragile: More Thoughts
I just ran across a pointer to this research on Bruce Schneier’s blog: Networking system components that are well-behaved in separation may create counter-intuitive emergent system behaviors, which are not well-behaved at all. For example, cooperative behavior might unexpectedly break down as the connectivity of interaction partners grows. “Applying this to the global network of […]
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The post Machine Fragile: More Thoughts appeared first on Packet Pushers Podcast and was written by Russ White.
Healthy Paranoia Show 12: The Saga of Terry Childs
Announcing the latest episode of Healthy Paranoia from Mrs. Y featuring the case of Terry Childs, the infamous former Network Administrator arrested for refusing to provide passwords for San Francisco’s FiberWAN system to management. She’s joined by Jeana Pieralde, Chief Security Officer for the City and County of San Francisco, along with two members of the […]
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The post Healthy Paranoia Show 12: The Saga of Terry Childs appeared first on Packet Pushers Podcast and was written by Mrs. Y.
The Technical Mind
I have worked in technology full-time for nearly fifteen years. Prior to this, I built PCs and was somewhat of a technical hobbyist. Occasionally, I am faced with the question, “How does one get into computers?” or “How can I get into computer networking?” There are many paths and correct answers to these questions. The […]
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The post The Technical Mind appeared first on Packet Pushers Podcast and was written by Paul Stewart.
When CDP doesn’t discover
Marko's myths of VLAN 1 post continues to drive a lot of traffic to my response about CDP, tagging and the magic properties of VLAN 1.Today I was introduced to a related phenomenon that I found interesting.
Backstory
CDP messages sent by switches are always in VLAN 1. If something other than VLAN 1 is the native VLAN on a particular trunk, then the CDP frame will be tagged with "1".
Funny Business
According to the post linked above there are related conditions that break CDP altogether.
The required elements are:
- A switch sending tagged CDP frames, either because it's using something other than VLAN 1 as the native VLAN or it's been configured with vlan dot1q tag native
- A router-on-a-stick that does NOT have a subinterface configured with encapsulation dot1q 1
Apparently the router, having no subinterface configured to receive frames tagged with "1", will toss incoming CDP frames without bothering to look inside to find the CDP message, killing CDP operation altogether. Bummer. And kind of unexpected.
I haven't tested this behavior, nor do I even have an IOS-XR (where the problem was found) box available. I suspect that IOS and IOS-XE systems might have a similar Continue reading
The Next Generation in Cloud-Scale Networking: The Arista 7500E
Today we are announcing our new 7500E modular switch, the fastest and densest modular switching platform in the industry, enabling cloud networks to scale to over 100,000 servers and millions of virtual machines.
The Arista 7500E is a remarkable 3X better than its predecessor. It offers 3X the number of ports, 3X the fabric bandwidth, 3X the packet buffer, 3X the supervisor performance, and 3X the power-efficiency, without a chassis or power upgrade.
But the real story of the 7500E it that it enables customers to build a universal cloud networking infrastructure for the worldʼs largest data centers that can handle even the most demanding workloads with ease.
Letʼs take a look inside this remarkable new switch.
3X the Fabric Bandwidth
The 7500E has 3.84 Tbps fabric bandwidth per slot, or 30 Tbps per 8-slot chassis, three times the bandwidth of the first generation 7500.
3X the Port Density
The 7508E supports 1152 10G, 288 40G or 96 100G wire-speed ports in a 11U chassis, the highest port density in the industry and three times the number of ports of the first generation 7500.
3X the Packet Buffer
The 7500E comes with a world-record 144 GByte of packet buffer per 8-slot chassis, Continue reading
VMware VCDX Lab: The Hardware
I have to admit I’m a big VMware fanboy. Wanting to master the art of virtualization, I’ve set out to build out a personal lab. My primary goal is to work my way up to the VCDX certification. The curious thing about building a VMware lab is that all parts need to be on the […]
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The post VMware VCDX Lab: The Hardware appeared first on Packet Pushers Podcast and was written by Douglas Hanks.
Show 145 – Talking OpenDaylight and SDN
A community show where we get Brent Salisbury and Ivan Pepelnjak to talk about the events of the last few weeks. In the end, the only thing we seemed to cover was OpenDaylight, ONS and various SDN topics. Open Networking Summit – Brent reports in. Talking SDN and OpenDaylight Ivan asks “will you install open […]
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The post Show 145 – Talking OpenDaylight and SDN appeared first on Packet Pushers Podcast and was written by Greg Ferro.
Nexus 7000 IO Module SKU Cheat Sheet
Wow the title of this post is a mouthful.
Similar to my previous post on the Nexus 2000 (Nexus 2000 Model Number Cheat Sheet), this post will explain what the letters and numbers mean in the Nexus 7000 IO module part numbers. This will allow you to quickly identify the characteristics of the card just by looking at the part number which in turn should help you out as you're building BOMs and picking the right card for the job.
Update July 2, 2013: Updated to reflect release of the Nexus 7700 and F3 modules.
IGP Route Multipathing
In preparation for an upcoming post, I was reminded about a commonly referred to feature in most IGPs - the concept of Equal-Cost Multipath, or simply ECMP. This is the idea that multiple routes with the same cost to a remote network should get placed in the routing table alongside each other and packets should load-balance over them to use the additional available paths. After all, it’s the same cost, so why not?IGP Route Multipathing
In preparation for an upcoming post, I was reminded about a commonly referred to feature in most IGPs - the concept of Equal-Cost Multipath, or simply ECMP. This is the idea that multiple routes with the same cost to a remote network should get placed in the routing table alongside each other and packets should load-balance over them to use the additional available paths. After all, it’s the same cost, so why not?A Data Center Delivers Apps – So Shouldn’t We Monitor App Delivery?
Dinner with His Toadishness, Derick Winkworth, the other night rolled into a 3+ hour discussion of avant garde ways to do networking. One of the adjunct topics that came up was that of ownership within IT. Ownership is a complex problem in the data center, because there’s many complex technologies at work. No one single […]
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The post A Data Center Delivers Apps – So Shouldn’t We Monitor App Delivery? appeared first on Packet Pushers Podcast and was written by Ethan Banks.
Machine Fragile
Yesterday, a “breaking news” tweet at 1:07 PM EDT from the Associated Press reported that two explosions had occurred at the White House and President Obama had been injured. The news immediately sent the Dow Jones Industrial Average down 143 points, as this graph at the London Telegraph shows. There’s also a lovely animated display […]
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The post Machine Fragile appeared first on Packet Pushers Podcast and was written by Russ White.
Quiz #13 – Frame Relay self pinging
You have recently joined a new company that still uses Frame Relay. For monitoring purposes, you implement a script that pings all interfaces of a router, but you notice that some of them are not ping-able. Why ?
It Works and It Should Be Better
You say, “It works – don’t fix it.” I hear, “It works – don’t touch it.” I’m also thinking that if you don’t touch it, then it’s never upgraded or changed. Is a static, unchanged network the best you can do to support your business ? Are you happy with just doing more of the same […]
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The post It Works and It Should Be Better appeared first on Packet Pushers Podcast and was written by Greg Ferro.
What can you learn in 5 minutes a day !
I believe in minimalism and what small focused actions can make for a person and small steps is what Juniper learning bytes is all about. Learning bytes is an online learning resource launched last year by Juniper education services organization as a free service. The nice thing about the learning bytes is that they are focused, [...] No related posts. Related posts brought to you by Yet Another Related Posts Plugin.Your Job Hunt is YOUR Responsibility
Earlier this week, I read the article below. This article took a strong stance that a recruiter works for the employer, not those seeking employment. I think there are some valid points made. However, my views are a little less extreme than that of the author. NEWSFLASH: A Recruiter is Not a Job Finder!. Frankly, […]
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The post Your Job Hunt is YOUR Responsibility appeared first on Packet Pushers Podcast and was written by Paul Stewart.