Epidemic Modeling(DES)

Introduction

One of the things I have been trying to play recently with is Discrete Event Simulation(DES). I think it is a powerful tool for validating ideas. In this post, we will look at a toy epidemic model to simulate SIS/SIR models.

In Epidemic modeling, there are two classic models - SIS and SIR models. The models divide the population into different categories corresponding to different stages of the epidemic.

Susceptible(S): Susceptible individuals can contract the disease.
Infected(I): Infected individuals have already been contracted the disease.
Recovered(R): Recovered individuals are recovered from the disease and can not be infected again.

SIS Model

In case of SIS, the main assumption is that an infected person can get infected again after recovering. The state transition diagram looks like:

SIS State Transition

$\beta$ is the probability of transitioning from Susceptible(S) to Infected(I)
$\mu$ is the probability of transitioning from Infected(I) to Susceptible(S)

SIR Model

In case of SIR, the main assumption is that an infected person can not get infected again. The state transition diagram looks like:

SIR State Transition

$\beta$ is the probability of transitioning from Susceptible(S) to Infected(I)
$\mu$ is the probability of transitioning from Infected(I) to Recovered(R)

SIS Simulation

We will have a generic Simulation class Continue reading

Cloudflare Pages is Lightning Fast

When we announced Cloudflare Pages in April, our goal wasn’t to bring just any web development tool to the table. As a front-end developer, it’s your responsibility to bring the ideas of your marketing, product and engineering teams to life by crafting a beautifully engaging experience for every customer. With all the hard work that goes into the development process — turning mock-ups to code, getting input from your team, staging and testing changes — you want the best performance possible for your site to showcase your work and optimize your customers’ experience.

Cloudflare Pages is the most secure and most scalable Jamstack platform to build and deploy your sites on the edge. But how is Pages so fast?

It comes down to three key reasons:

Pages is built on one of the fastest networks in the world, putting us within 50 ms of 95% of the world’s Internet-connected population. Delivering Pages from this network is the basis of our speed.
Cloudflare helps define and implement next generation standards, like QUIC + HTTP/3 and Early Hints, that push Pages performance to the next level.
Pages has a killer developer experience that makes it easy to build the fastest websites on Continue reading

Profiling Your Workers with Wrangler

In the year since Cloudflare’s launch of Workers Unbound, developers have unlocked the ability to run computationally intensive workloads on the Cloudflare edge network — like image processing, game logic, and other complex algorithms. With all that additional computing power comes a host of questions around performance. Our customers often ask us how they can profile or monitor their Workers to see where they spend the most CPU time, or to see whether their changes improve performance.

Here at Cloudflare, we not only want to build the fastest, most affordable, and most flexible compute platform at the edge; we also want to make the lives of our developers easier in building their applications. To do this, Cloudflare has begun to integrate with existing tools — places our developers feel comfortable and efficient in their day-to-day work. To help measure performance of our customers’ Workers, we’re beginning to integrate with the Chrome DevTools protocol. Just like you can use chrome://inspect to debug your Node backend, you can also use it to profile your Cloudflare Workers.

Introducing Chrome DevTools Integration (Beta)

We’re starting off this integration with beta support for local CPU profiling, using Wrangler. To show off how to use this Continue reading

APIs and Department Stores

This week I tweeted something from a discussion we had during Networking Field Day that summed up my feelings about the state of documentation of application programming interfaces (APIs):

APIs are like Walmart. Everything you want is in there, but they randomly move things around every few months to see who’s paying attention.
— Tom Hollingsworth (@NetworkingNerd) September 15, 2021

I laughed a bit as I wrote it because I’ve worked in department stores like Walmart in the past and I know the reasons why they tend to move things around. Comparing that to the way that APIs are documented is an interesting exercise in how people think about things like new capabilities and notification of changes.

Branding Exercises

In case you weren’t aware, everything in your average department store is carefully planned out. The things placed in the main aisles are decided on weeks in advance due to high traffic. The items placed at the ends of the aisles, or endcaps, are placed there to highlight high margin items or things that are popular enough to be sought out by customers. The makeup of the rest of the store is determined by a lot of metrics.

There are a Continue reading

Will AMD Get Back Into Arm Server Chips?

There was a bit of a kerfuffle this week when it looked like AMD was changing its position a little bit on whether or not it would get back into designing and selling server chips based on the Arm architecture. …

Will AMD Get Back Into Arm Server Chips? was written by Timothy Prickett Morgan at The Next Platform.

How to Simplify Your Journey to Zero Trust with NSX Workshops

At its core, Zero Trust is an operational framework that helps enterprises secure modern network environments. Zero Trust insists organizations strip away ambiguity from their security and focus on the basics: committing to a risk-based approach across end-users, networks, data, devices, and much more. If you’re ready to take the next step toward built-in, Zero Trust networking (ZTN), we can help. Learn how to successfully implement Zero Trust networking and segmentation strategies at one of our upcoming NSX Network Security Workshop Sessions on Tuesday, September 28, 2021 or on Wednesday, September 29, 2021.

During these live virtual events, Patricio Villar, Principal Network Architect and VMware Certified Expert/Network Virtualization, will cover Zero Trust foundational concepts, including:

How to identify communication paths to segment and build policy to protect your data center
How implementing NSX security supports ZTN framework
How to easily implement stronger distributed security with VMware NSX

NSX Network Security Workshop topics include:

If you’re ready to simplify Zero Trust so you can have simply zero worries, grab your spot and register today.

See you there!

The post How to Simplify Your Journey to Zero Trust with NSX Workshops appeared first on Network and Security Virtualization.

Weekend Reads 091721

Relationships also evolved during this uprooting of typical routines. Pandemic “pods” helped some Americans maintain connection, but they complicated relationships and family dynamics at the same time.

Attackers are actively exploiting a Microsoft remote code execution vulnerability using malicious Office files, the tech giant has warned.

“When you have a high percentage of all AI activity in Bay Area metros, you may be overconcentrating, losing diversity, and getting groupthink in the algorithmic economy. It locks in a winner-take-most dimension to this sector, and that’s where we hope that federal policy will begin to invest in new and different AI clusters in new and different places to provide a balance or counter.”

Email isn’t just a communication tool; it’s also an identifier and a security measure. Companies use it to create profiles of you when you start accounts with them and it often doubles as your username.

However, it looks like most phishing emails could be used to obtain user credentials according to the 2021 Annual State of Phishing Report by Cofense. After analyzing millions of emails, Cofense found that 57% are credential phishing emails.

Computer programmers are a pretty predictable bunch. Every time they approach legacy code, the gut Continue reading

Heavy Networking 598: The Future Of Networking – Quantum Communications With Joshua Slater

Today's Heavy Networking gets entangled in a discussion about quantum communications or quantum networking. We discuss qubits, the challenges of moving them across a network, use cases such as key distribution, and more. Our guest is Dr. Joshua Slater.

Heavy Networking 598: The Future Of Networking – Quantum Communications With Joshua Slater

The post Heavy Networking 598: The Future Of Networking – Quantum Communications With Joshua Slater appeared first on Packet Pushers.

Benchmarking Edge Network Performance: Akamai, Cloudflare, Amazon CloudFront, Fastly, and Google

During Speed Week we’ve talked a lot about services that make the web faster. Argo 2.0 for better routing around bad Internet weather, Orpheus to ensure that origins are reachable from anywhere, image optimization to send just the right bits to the client, Tiered Cache to maximize cache hit rates and get the most out of Cloudflare’s new 25% bigger network, our expanded fiber backbone and more.

Those things are all great.

But it’s vital that we also measure the performance of our network and benchmark ourselves against industry players large and small to make sure we are providing the best, fastest service.

We recently ran a measurement experiment where we used Real User Measurement (RUM) data from the standard browser API to test the performance of Cloudflare and others in real-world conditions across the globe. We wanted to use third-party tests for this, but they didn’t have the granularity we wanted. We want to drill down to every single ISP in the world to make sure we optimize everywhere. We knew that in some places the answers we got wouldn’t be good, and we’d need to do work to improve our performance. But without detailed analysis across the Continue reading

Announcing Project Turpentine: an easy way to get off Varnish

When Varnish and the Varnish Configuration Language (VCL) were first introduced 15 years ago, they were an incredibly powerful combination to configure caching on servers (and your networks). It seemed a logical choice for a language to configure CDNs — caching in the cloud.

A lot has changed on the Internet since then.

In particular, caching is just one of many things that “CDNs” are expected to do: load balancing, DDoS protection, rate limiting, transformations, synthetic responses, routing and more. But above all what “CDNs” need to be is programmable, not just configurable.

Configuration went from a niche activity to a much more common — and often involved — requirement. We’ve heard from a lot of teams that want to remove critical dependencies on the one person they have who knows how to make configuration changes — because they’re the only one on the team who knows how to write in VCL.

But it’s not just about who can write VCL — it’s what VCL is increasingly being asked to do. A lot of our customers have told us that they have much greater expectations for what they expect the network to do: they don’t just want to configure Continue reading

How to use the sleep command: 2-Minute Linux Tips

In this Linux tip, learn how to use the sleep command. The sleep command introduces a pause on the command line or in a script.

Route Replication the Easy Way

Easy Virtual Network (EVN) was a technology Cisco came up with back in the days to make it easier to implement VRFs without the pain of running VRF lite or the complexity of running a full MPLS + BGP network. It was actually a pretty cool technology but never became mainstream. However, as part of this technology, Cisco also made it easier to replicate, or in other words leak, routes between VRFs. You don’t need the rest of EVN to do this and this simplified way of replicating routes have kind of been forgotten by the industry. I thought I would share with you the ease of replicating routes with this feature even without BGP.

We have a straight forward topology like the one below:

The USERS switch is a L2 switch and all the L3 configuration is in the CORE router. We have implemented segmentation in the network so we have a USERS VRF and then we have a SERVICES VRF for shared services such as DNS and DHCP. Because these services are in a separate VRF, we will not have reachability to them from the USERS VRF. This lab will use the following IP addresses:

User – 10. Continue reading

Interesting Concept: Time Dilation

I loved the Time Dilation blog post by Seth Godin. It explains so much, including why I won’t accept a “quick conf call to touch base and hash out ideas” from someone coming out of the blue sky – why should I be interested if they can’t invest the time to organize their thoughts and pour them into an email.

The concept of “creation-to-consumption” ratio is also interesting. Now I understand why I hate unedited opinionated chinwagging (many podcasts sadly fall into this category) or videos where someone blabbers into a camera while visibly trying to organize their thoughts.

Just FYI, these are some of the typical ratios I had to deal in the past:

Interesting Concept: Time Dilation

Just FYI, these are some of the typical ratios I had to deal in the past:

Out of the Box Infrastructure Connectivity Options

There are plenty of physical layer connectivity options available these days. Be sure to consider all of them before your next upgrade.

The importance of Calico’s pluggable data plane

This post will highlight and explain the importance of a pluggable data plane. But in order to do so, we first need an analogy. It’s time to talk about a brick garden wall!

Imagine you have been asked to repair a brick garden wall, because one brick has cracked through in the summer sun. You have the equipment you need, so the size of the job will depend to a great extent on how easily the brick can be removed from the wall without interfering with all the ones around it. Good luck.

Now that we have that wonderful imagery in mind, let’s look at how to go about designing walls — and how they can be maintained.

About software coupling: Fixing walls and designing great walls

“Coupling” is the term used to describe the interdependence between pieces of software. Closely coupled systems are interdependent and difficult to separate; loosely coupled systems are more like building blocks designed to work together, but they come apart cleanly. So, since the bricks in our garden wall are closely coupled (in this case, by cement), attempting to remove just one creates difficult challenges.

We can think of software as being built in “walls,” Continue reading

Cisco forecasts a bright future for network, app, hybrid work technologies

In a wide-ranging Investor Day conference Cisco executives outlined what they described as a $900 billion total market of high-level technology targets the networking giant expects to be a dominant force in developing toward in the next four years.Those targets include the six areas Cisco has been building toward for the past couple years, including agile networks, optimized applications, hybrid work, the Internet of the future, end-to-end security and edge networking capabilities but also other areas such as cloud security, hybrid cloud, IoT and more. The 10 most powerful companies in enterprise networking 2021 “We have built a portfolio designed for the modern world, and driven compelling new innovation from Cisco Plus and the Webex Suite to Silicon One and Secure X just a few examples of key technologies that we have provided over the past few years,” said Chuck Robbins, Cisco CEO. To read this article in full, please click here

The Tipping Point For PCI-Express Fabrics

In the longest of runs, say within the next five to ten years, in the large datacenters of the world, the server chassis as we know it will no longer exist. …

The Tipping Point For PCI-Express Fabrics was written by Timothy Prickett Morgan at The Next Platform.

Regulating Big Tech. This Time, for sure!

There is a growing unease within the US and elsewhere over the extraordinary rise of these technology giants, not just in monetary terms but in terms of their social power as well. There is a growing sentiment that the current situation looks like it will never be adequately corrected by just competitive pressures within market itself. Some further forms of regulatory intervention will be needed to force a fundamental realignment of these players. In so doing, it appears that regulators appear to be finally catching up with the online world in the US, in Europe and in China.

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