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Category Archives for "Networking"

Tailoring SD-WAN to fit your needs

SD-WAN resources What is SD-WAN and what does it mean for networking, security, cloud? 10 SD-WAN features you're probably not using but should be SD-WAN may be the key to smart network services SD-WAN and analytics: A marriage made for the new normal Native SD-WAN monitoring tools are not enough, survey says Why is it that we always seem to think that we can adopt a technology that has seriously revolutionary pieces by just buying it and hooking it up? This, despite the undeniable fact that everything in tech is getting more sophisticated, more complex? Software-defined WAN is a technology like that, and because all SD-WANs aren’t the same, or even close to the same, you’ll have to do some digging to make SD-WAN your own.To read this article in full, please click here

How to scale a Wi-Fi network

Although it’s tempting to just deploy more access points (APs) when expanding your Wi-Fi network, there are many considerations to take in account first in order to get a high-performing result without overspending. Wi-Fi resources Test and review of 4 Wi-Fi 6 routers: Who’s the fastest? How to determine if Wi-Fi 6 is right for you Five questions to answer before deploying Wi-Fi 6 Wi-Fi 6E: When it’s coming and what it’s good for Step one is to clearly understand what you are trying to achieve, then analyze the current setup so you know how well the network serves the coverage area, and only then go about designing and deploying the APs.To read this article in full, please click here

What You Can Learn from the AWS Tokyo Outage

Jason Yee Jason is director of advocacy at Gremlin where he helps companies build more resilient systems by learning from how they fail. He also helps lead Gremlin's internal chaos engineering practices to make it more reliable. In the movies, it seems like Tokyo is constantly facing disasters — natural ones in the forms of earthquakes and tsunamis, and unnatural ones like giant kaiju and oversized robots. On the morning of Sept. 1, the mechanized behemoth was Amazon Web Services. At around 7:30 am JST, AWS began experiencing networking issues in its AP-Northeast-1 region based in Tokyo. The outage affected business across all sectors, from financial services to retail stores, travel systems and telecommunications. Despite the troubles with not being able to access money, purchase goods, travel or call each other, the Japanese people demonstrated resilience, proving that at least some things from the movies are true. However, the financial losses due to the outage are expected to be huge. After the six-hour outage, AWS explained the issue

Non-Stop Forwarding 101

Non-Stop Forwarding (NSF) is one of those ideas that look great in a slide deck and marketing collaterals, but might turn into a giant can of worms once you try to implement them properly (see also: stackable switches or VMware Fault Tolerance).

NSF has been around for at least 15 years, so I’m positive at least some vendors got most of the details right; I’m also pretty sure a few people have scars to prove they’ve been around the non-optimal implementations.
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Best Questions to Ask In Job Interviews

Usually interviews are not supposed to make the person anxious and uncomfortable. As a part of an interviewer the questions should be asked in an extremely comfortable yet appropriate way, which does not make the person feel like he is being scrutinized or grilled. There are multiple techniques and ways to go about this process. However, when the interviewer asks the person whether or not they want to ask any questions regarding the company, their role, the job or position being offered, here are a few questions that can easily make one understand and get a deeper insight on what is being offered to them.

One needs to understand that as much as being able to answer the interviewer’s question is important; it is also considerably important to ask them the following significant questions. This will make them come off as a well balanced, ideal, and informative person which in return can help them stand out from others.

What Could Your Day-To-Day responsibilities look like?

Getting a deeper insight on the functionality of the job is extremely ideal and appropriate to ask during an interview. One has to know what their daily work load, their responsibilities, and the expectations could Continue reading

Switching to the i3 window manager

I have been using the awesome window manager for 10 years. It is a tiling window manager, configurable and extendable with the Lua language. Using a general-purpose programming language to configure every aspect is a double-edged sword. Due to laziness and the apparent difficulty of adapting my configuration—about 3000 lines—to newer releases, I was stuck with the 3.4 version, whose last release is from 2013.

It was time for a rewrite. Instead, I have switched to the i3 window manager, lured by the possibility to migrate to Wayland and Sway later with minimal pain. Using an embedded interpreter for configuration is not as important to me as it was in the past: it brings both complexity and brittleness.

i3 dual screen setup
Dual screen desktop running i3, Emacs, some terminals, including a Quake console, Firefox, Polybar as the status bar, and Dunst as the notification daemon.

The window manager is only one part of a desktop environment. There are several options for the other components. I am also introducing them in this post.

Comparing Forwarding Performance of Data Center Switches

One of my subscribers is trying to decide whether to buy an -EX or an -FX version of a Cisco Nexus data center switch:

I was comparing Cisco Nexus 93180YC-FX and Nexus 93180YC-EX. They have the same port distribution (48x 10/25G + 6x40/100G), 3.6 Tbps switching capacity, but the -FX version has just 1200 Mpps forwarding rate while EX version goes up to 2600 Mpps. What could be the reason for the difference in forwarding performance?

Both switches are single-ASIC switches. They have the same total switching bandwidth, thus it must take longer for the FX switch to forward a packet, resulting in reduced packet-per-seconds figure. It looks like the ASIC in the -FX switch is configured in more complex way: more functionality results in more complexity which results in either reduced performance or higher cost.

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Network Centrality and Robustness

Introduction

A system is robust if the failure of some components doesn’t affect its function. As network engineers, we face various types of network failures like link, node failures all the time.

Generally, we use various Network modeling tools like Cariden(WAE), WANDL, etc. to model failures and see how the network reacts under a given failure condition. The components which are in play are:

  1. Type and Number of failures. Type: Link, Node. Number of Failures: Single or Double.
  2. Routing protocols running on top of the network and there reaction to the failure. Example: RSVP-TE, Pure IGP, SR-TE etc.
  3. Network flows and their volume.
  4. Network Topology.

In this blog post, we will focus purely on #4 Network topology and certain characteristics of topology, which may make them more robust than other topologies.

Key Idea

The network topology may have some critical nodes. If we can identify them and take them out of the service, they will significantly impact the functionality of the network. For example, in the case of a Hub and Spoke topology, if a Hub is out of service, it affects all the spokes vs. a spoke out of service. We can make this hub and spoke topology more Continue reading

pygnmi 11. Measuring Automated Testing with Coverage.py and Pytest

Hello my friend,

It is been a while since we posted our last blogpost, which was touching Infrastructure aspects of building Multi Server Cloud with ProxMox. After summer break we continue our blogging and developing activities at Karneliuk.com. Today we’ll show some backstage of the software development of the pygnmi.



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prior permission of the author.

What is Automation? Network Automation?

In a nutshell, Automation and Network Automation are just subset of tasks from a broader topic called Software Development. With the move of the world towards Industry 4.0, the digital economy growth and others, all sort of applications are becoming more widely used. In order you create a history, and not being a part of that in the past, you shall know the principles of software development and be able to create applications yourselves. Sounds complicated? It may be, indeed. However, with our Network Automation Training you definitely will have a break-through in the software development world.

At our Continue reading

Getting Blasted by Backdoors

Open Door from http://viktoria-lyn.deviantart.com/

I wanted to take minute to talk about a story I’ve been following that’s had some new developments this week. You may have seen an article talking about a backdoor in Juniper equipment that caused some issues. The issue at hand is complicated at the linked article does a good job of explaining some of the nuance. Here’s the short version:

  • The NSA develops a version of Dual EC random number generation that includes a pretty substantial flaw.
  • That flaw? If you know the pseudorandom value used to start the process you can figure out the values, which means you can decrypt any traffic that uses the algorithm.
  • NIST proposes the use of Dual EC and makes it a requirement for vendors to be included on future work. Don’t support this one? You don’t get to even be considered.
  • Vendors adopt the standard per the requirement but don’t make it the default for some pretty obvious reasons.
  • Netscreen, a part of Juniper, does use Dual EC as part of their default setup.
  • The Chinese APT 5 hacking group figures out the vulnerability and breaks into Juniper to add code to Netscreen’s OS.
  • They Continue reading

Weekend Reads 090321


In our professional practice, we are often called to perform rapid, approximate calculations without a calculator. Any available scrap of paper such as an envelope will do to scribble on.


The wireless carrier initially confirmed 47.8 million former, prospective and existing customers were impacted, but found the data of an additional 5.3 million customers was compromised.


A recent measurement study suggests that BBR is already being deployed by 22% of the Alexa Top 20k websites on the Internet.


Zero trust improves the security of IT environments as demonstrated over time by reduced attacker dwell time. The challenge many people face is understanding where to begin.


In recent months, we’ve been sharing information collected by APNIC honeypots with our community at several conferences, seminars, and workshops. ‘Information’ here basically means observations from the logs/traffic, as well as artefacts collected (such as scripts and binaries).


The Internet plays a crucial role in our increasingly digital daily lives. But who shapes and governs the patchwork that enables this essential utility? And how do their actions bear on the rights and interests of users all over the world?


We are facing the same paradox with respect to privacy and influence on the Continue reading

Black Friday Downtime: How to Avoid Impacts on Your Business

Hannah Culver Hannah is a solutions marketer at PagerDuty interested in how real-time urgent work plays out across all industries in this digital era. It’s a brisk Friday morning in November. You’re sipping your coffee and mentally preparing yourself for the day that’ll define your fiscal year. How will you fare this Black Friday? Are your teams prepared? We’ve all heard the 2020 Holiday Shopping Season Report, “The online holiday season exceeded $188B resulting in a strong growth rate of 32% over the 2019 season.” This trend didn’t start with COVID-19, however. A

Heavy Networking 596: Weaponizing Firewalls And Middleboxes For DDoS Attacks

Today's Heavy Networking podcast dives into academic research on DDoS attack techniques. Our guests have published a paper about how the TCP protocol and middleboxes such as firewalls can be weaponized by bad actors and used in reflective amplification attacks. We discuss technical details, how they performed this research, potential countermeasures, and more.

The post Heavy Networking 596: Weaponizing Firewalls And Middleboxes For DDoS Attacks appeared first on Packet Pushers.

Heavy Networking 596: Weaponizing Firewalls And Middleboxes For DDoS Attacks

Today's Heavy Networking podcast dives into academic research on DDoS attack techniques. Our guests have published a paper about how the TCP protocol and middleboxes such as firewalls can be weaponized by bad actors and used in reflective amplification attacks. We discuss technical details, how they performed this research, potential countermeasures, and more.

Video: Introduction to Network Addressing

A friend of mine pointed out this quote by John Shoch when I started preparing the Network Stack Addressing slide deck for my How Networks Really Work webinar:

The name of a resource indicates what we seek, an address indicates where it is, and a route tells us how to get there.

You might wonder when that document was written… it’s from January 1978. They got it absolutely right 42 years ago, and we completely messed it up in the meantime with the crazy ideas of making IP addresses resource identifiers.

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