Before Facebook, the Late Ward Christensen Booted Up the First Social Network

Back in the 70s, if you wanted to be online, you had to be a college student, researcher, or in the military to be on the internet. That was it. Joe or Jane User? Forget about it. Then, during a Chicago blizzard, a young computer scientist, online services such as CompuServe started as early as 1969. However, unlike the free BBSs, these services could cost as much as $30 an hour in 1970s dollars or $130 an hour in today’s money. XMODEM file transfer protocol in 1977. This innovative method broke binary files into packets, ensuring reliable delivery over unstable analog telephone lines. XMODEM became a cornerstone of early online file sharing and inspired numerous subsequent file transfer protocols. While considered inefficient by today’s standards, XMODEM established key concepts that are still used in file transfers. These include breaking data into packets for transmission, using checksums or CRCs for error detection, and implementing handshaking between sender and receiver. Thanks to XMODEM, people began sharing files with one another. This, in turn, helped create

The story of web framework Hono, from the creator of Hono

Hono is a fast, lightweight web framework that runs anywhere JavaScript does, built with Web Standards. Of course, it runs on Cloudflare Workers.

It was three years ago, in December 2021. At that time, I wanted to create applications for Cloudflare Workers, but the code became verbose without using a framework, and couldn't find a framework that suited my needs. Itty-router was very nice but too simple. Worktop and Sunder did the same things I wanted to do, but their APIs weren't quite to my liking. I was also interested in creating a router — a program that determines which action is executed based on the HTTP method and URL path of the Request — made of a Trie tree structure because it’s fast. So, I started building a web framework with a Trie tree-based router.

 “While trying to create my applications, I ended up creating my framework for them.” — a classic example of yak shaving. However, Hono is now used by many developers, including Cloudflare, which uses Hono in core products. So, this journey into the depths of yak shaving was ultimately meaningful.

Write once, run anywhere

Hono truly runs anywhere — not just on Cloudflare Continue reading

Comparing IP and CLNP: Finding Adjacent Nodes

Now that we know a bit more about addresses in a networking stack (read the whole series) and why CLNP uses node addresses while TCP/IP uses interface addresses, let’s see how they solve common addressing problems like finding adjacent nodes.

Let’s start with the elephant in the room: how do you know whether you can reach a host you want to communicate with directly? In the following diagram, how does A know whether B is sitting next to it?

Read more …

Adding ADCS Role to ISE Lab Domain Controller

This post describes how to install Active Directory Certificate Services (ADCS) onto a domain controller. It’s for labbing purposes which means I’m going to run this all on a single server instead of a more realistic setup with offline root, issuing CA, and possibly intermediate CA. Don’t use this post for anything designed to go into production!

To add the ADCS role. Go to Server Manager, click Add roles and features. Click Next until you get to Server Roles. Select Active Directory Certificate Series:

Click Add Features. Click Next. Click Next. Then a warning is displayed that it’s not possible to change the computer name or domain settings:

Click Next. Select Certification Authority and Certification Authority Web Enrollment:

Selecting Certification Authority Web Enrollment will install IIS and a small web site will be built to provide certificate services.

Click Add Features. Click Next. Click Next. Select Restart the destination server automatically if required:

Click Install. The installation starts:

When the installation has finished, click Close. Click AD CS in Server Manager. Click More… where it says Configuration required for Active Directory Certificate Services:

Click Configure Active Directory Certificate Services on the destination server:

Select an Continue reading

Cloud Native Networking as Kubernetes Starts Its Second Decade

Kubernetes recently Kubernetes to enter its rebellious phase. It will experience awkward growth spurts (as new use cases force Kubernetes to adapt); it might go through an identity crisis (is it a platform or is it an API?); it will ask for less supervision and more independence (and rely on AI-driven tooling to require less direct human oversight). As Kubernetes matures into adolescence, let’s consider how its networking and security circulatory systems grow and adapt. With eBPF, the technology that lets you run custom programs within the Linux (and, soon, Windows) kernel, is not stopping. Beyond networking and security (and the Tetragon projects I work on), more use cases are emerging as you will learn during KubeCon: Measuring Introducing Continue reading

Analysis of the EPYC 145% performance gain in Cloudflare Gen 12 servers

Cloudflare's network spans more than 330 cities in over 120 countries, serving over 60 million HTTP requests per second and 39 million DNS queries per second on average. These numbers will continue to grow, and at an accelerating pace, as will Cloudflare’s infrastructure to support them. While we can continue to scale out by deploying more servers, it is also paramount for us to develop and deploy more performant and more efficient servers.

At the heart of each server is the processor (central processing unit, or CPU). Even though many aspects of a server rack can be redesigned to improve the cost to serve a request, CPU remains the biggest lever, as it is typically the primary compute resource in a server, and the primary enabler of new technologies.

Cloudflare’s 12th Generation server with AMD EPYC 9684-X (codenamed Genoa-X) is 145% more performant and 63% more efficient. These are big numbers, but where do the performance gains come from? Cloudflare’s hardware system engineering team did a sensitivity analysis on three variants of 4th generation AMD EPYC processor to understand the contributing factors.

For the 4th generation AMD EPYC Processors, AMD offers three architectural variants: 

  1. mainstream classic Zen 4 cores, codenamed Continue reading

Protect against identity-based attacks by sharing Cloudflare user risk scores with Okta

Cloudflare One, our secure access service edge (SASE) platform, is introducing a new integration with Okta, the identity and access management (IAM) vendor, to share risk indicators in real-time and simplify how organizations can dynamically manage their security posture in response to changes across their environments.

For many organizations, it is becoming increasingly challenging and inefficient to adapt to risks across their growing attack surface. In particular, security teams struggle with multiple siloed tools that fail to share risk data effectively with each other, leading to excessive manual effort to extract signals from the noise. To address this complexity, Cloudflare launched risk posture management capabilities earlier this year to make it easier for organizations to accomplish three key jobs on one platform:

  1. Evaluating risk posed by people by using first-party user entity and behavior analytics (UEBA) models

  2. Exchanging risk telemetry with best-in-class security tools, and

  3. Enforcing risk controls based on those dynamic first- and third-party risk scores.

Today’s announcement builds on these capabilities (particularly job #2) and our partnership with Okta by enabling organizations to share Cloudflare’s real-time user risk scores with Okta, which can then automatically enforce policies based on that user’s risk. In this way, organizations can adapt Continue reading

Adding DHCP Role to ISE Lab Domain Controller

In the previous post, Setting up Active Directory for ISE Lab, we enabled Active Directory Domain Services. The DNS role was also added automatically as part of this process. In this post, we’ll add DHCP to the server.

Go to Server Manager, click Add roles and features. Click Next until you get to Server Roles. Select DHCP Server. This will display a window asking if required services should be installed:

Click Add Features. Click Next until getting to the Confirmation screen. Select Restart the destination server automatically if required. Since this is a lab, it’s OK to restart.

Select Yes. Then Click Install. The installation starts:

After the installation finishes, click Close.

The DHCP role has been added:

Let’s configure two DHCP scopes, one for employees and one for guests. Open the DHCP app, then expand the server and then IPv4. Right click on IPv4 and select New Scope…

This launches the New Scope Wizard:

Give the scope a name and a description:

Click Next. Then configure starting IP, ending IP, and the subnet mask:

Click Next. I’m not adding any exclusions so clicking Next again. Then configure the lease duration, I’m setting it to 1 day instead of Continue reading

OCP Global Summit 2024

AI networking is a popular topic at the up coming OCP Global Summit in San Jose, California, with an entire morning on Wednesday October 16 devoted to the subject.
Of particular interest is the talk, Leveraging open technologies to monitor packet drops in AI cluster fabrics, by Aldrin Isaac, eBay, describing the challenge, AI clusters operate most efficiently over lossless networks for optimum job completion times which can be significantly impacted by dropped packets. Although networks can be designed to minimize packet loss by choosing the right network topology, optimizing network devices and protocols, an effective monitoring and troubleshooting network performance tool is still required. Such tool should capture packet drops, raise notifications and identify various drop reasons and pin point where the drops caused congestions. In turn, it allows the governing management application to tune configurations of relevant infrastructure components, including switches, NICs and GPU servers.

The talk will share the results and best practices of a TAM (Telemetry and Monitoring) solution being prepared for deployment at eBay. It leverages OCP’s SAI and open sFlow drop notification technologies as part of eBay’s ongoing initiatives to adopt open networking hardware and community SONiC for its data centers.

The sFlow Continue reading

AI for Network Engineers: Backpropagation Algorithm

 Introduction 


This chapter introduces the training model of a neural network based on the Backpropagation algorithm. The goal is to provide a clear and solid understanding of the process without delving deeply into the mathematical formulas, while still explaining the fundamental operations of the involved functions. The chapter also briefly explains why, and in which phases the training job generates traffic to the network, and why lossless packet transport is required. The Backpropagation algorithm is composed of two phases: the Forward pass (computation phase) and the Backward pass (adjustment and communication phase).

In the Forward pass, neurons in the first hidden layer calculate the weighted sum of input parameters received from the input layer, which is then passed to the neuron's activation function. Note that neurons in the input layer are not computational units; they simply pass the input variables to the connected neurons in the first hidden layer. The output from the activation function of a neuron is then used as input for the connected neurons in the next layer. The result of the activation function in the output layer represents the model's prediction, which is compared to the expected value (ground truth) using the error function. The output Continue reading

How Do You Get Experience in IT?

A question I often get is, how do you get experience in IT? For people trying to break into this industry, what can they do to gain experience? How can they showcase that experience to a potential employer even if they are applying for their first job? Breaking into a new industry can be the most difficult thing, you lack experience and most of all you probably lack a network. Here are my thoughts on how you can gain that experience.

University studies

The ROI on university studies will vary depending on if you live in a country like me where studies are financed by tax and there is no tuition, or in a country where it can be very costly. That’s not the argument here, university studies can give some things that is difficult to achieve in any other way. I did three years at a university and here’s why I think it’s really valuable.

Time – Having two or three years of dedicated studies is a luxury you won’t have at any other point in your career. You have a full-time job and trying to learn a new discipline on top of that is going to be much Continue reading

Using BGP NO_EXPORT Community to Filter Transit Routes

In previous BGP policy lab exercises, we covered several mechanisms you can use to ensure your autonomous system is not leaking transit routes (because bad things happen when you do, particularly when your upstream ISP is clueless).

As you probably know by now, there’s always more than one way to get something done with BGP. Today, we’ll explore how you can use the NO_EXPORT community to filter transit routes.

Click here to start the lab in your browser using GitHub Codespaces (or set up your own lab infrastructure). After starting the lab environment, change the directory to policy/d-no-export and execute netlab up.

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