Poor man’s Traffic Engineering
Segment Routing allows the network operator to deploy Traffic Engineering even with the most basic routers that support the bare minimum of features.
What is traffic engineering
Traffic engineering is a set of techniques to influence the path a particular …
Worth Exploring: Free, OpenSource IPv6 Textbook
Nick Buraglio and Brian E. Carpenter published a free, open-source IPv6 textbook.
The book seems to be in an early (ever-evolving) stage, but it’s well worth exploring if you’re new to the IPv6 world, and you might consider contributing if you’re a seasoned old-timer.
It would also be nice to have a few online labs to go with it ;)
Napalm Configuration Management With Arista EOS
Hi all, welcome back to the Packetswitch blog. In today's post, we'll explore how to use NAPALM for managing device configurations. We'll focus on Arista EOS as our example. We'll cover the methods available in NAPALM and how to push, commit and revert configurations on Arista devices.
We'll start by explaining what NAPALM is and why you might want to use it. Then we'll move on to a few examples and take a look at what happens behind the scenes. This approach will give you a clear understanding of NAPALM's role in network configuration management and how it works with Arista EOS devices.
What is Napalm?
NAPALM stands for Network Automation and Programmability Abstraction Layer with Multivendor support. It's a Python library that helps network engineers manage and automate different network devices using a common set of functions. NAPALM solves the problem of dealing with multiple vendor-specific interfaces by providing a unified way to interact with network devices from various manufacturers. This means you can use the same code to manage devices from Cisco, Juniper, Arista, and others, saving time and reducing the complexity of network automation tasks.
A Beginner’s Guide to NAPALM Network Automation
In this blog post, we Continue reading
An AX.25 implementation in Rust
After having written a user space AX.25 stack in C++, I got bitten by the Rust bug. So this is the third time I’ve written an AX.25 stack, and I’ve become exceedingly efficient at it.
Here it is:
The reason for a user space stack remains from last time, but this time:
- It’s written in Rust. Yay! I know people say Rust has a honeymoon period, but I guess that’s where I am, still.
- It’s a normal library first. The previous C++ implementation started off as microservices, which in retrospect was needlessly complex and put the cart before the horse.
I’ve added almost an excessive amount of comments to the code, to cross reference with the specs. The specs that have a few bugs, by the way.
Rust
I’m not an expert in Rust, but it allows for so much more confidence in your code than any other language I’ve tried.
I think I know enough Rust to know what I don’t fully know. Sure, I’ve successfully added lifetime annotations, created macros, and built async code, but I’m not fluent in those yet.
Interestingly, Continue reading
Fixing layout shifts caused by web fonts
In 2020, Google introduced Core Web Vitals metrics to measure some aspects of real-world user experience on the web. This blog has consistently achieved good scores for two of these metrics: Largest Contentful Paint and Interaction to Next Paint. However, optimizing the third metric, Cumulative Layout Shift, which measures unexpected layout changes, has been more challenging. Let’s face it: optimizing for this metric is not really useful for a site like this one. But getting a better score is always a good distraction. 💯
To prevent the “flash of invisible text” when using web fonts, developers should
set the font-display property to swap in @font-face rules. This method
allows browsers to initially render text using a fallback font, then replace it
with the web font after loading. While this improves the LCP score, it causes
content reflow and layout shifts if the fallback and web fonts are not
metrically compatible. These shifts negatively affect the CLS score. CSS
provides properties to address this issue by overriding font metrics when using
fallback fonts: size-adjust,
ascent-override, descent-override,
and line-gap-override.
Two comprehensive articles explain each property and their computation methods in detail: Creating Perfect Font Fallbacks in CSS and Improved Continue reading
Dell’s AI Server Business Now Bigger Than VMware Used To Be
We have been watching the big original equipment manufactures like a hawk to see how they are generating revenues and income from GPU-accelerated system sales. …
Dell’s AI Server Business Now Bigger Than VMware Used To Be was written by Timothy Prickett Morgan at The Next Platform.
HN747: Automate The Easy Things
Our Heavy Networking guest today is Hans Driessens, and we sat down at AutoCon1 to talk through some of his network automation projects. Hans shares his journey from a service engineer to a consultant specializing in network automation. We discuss the evolution of programming languages, the importance of foundational programming skills, and the practicalities of... Read more »Explore ContainerLab: Simulate Complex Network Topologies with Docker Containers
I stumbled across this tool, while am always a fan of VRNET-LAB https://github.com/vrnetlab/vrnetlab and it operates on docker containers, i could not get it properly bridge it with Local network meaning reachability to internet is something that I never worked on.
A container lab is a virtualized environment that utilises containers to create and manage network testing labs. It offers a flexible and efficient way to simulate complex network topologies, test new features, and perform various network experiments.
One striking feature that i really liked about containerlab is that representation is in a straight yaml which most of the network engineers now a days are Familiar with and its easy to edit the representation.
Other advantages
- host mappings are done automatically
- Traffic capture is done with ease
Host mappings after spinning up the lab
Slide explaining the capture process – Courtesy Petr Ankudinov (https://arista-netdevops-community.github.io/building-containerlab-with-ceos/#1)
https://containerlab.dev/quickstart/ – Will give you how to do a quick start and install containerlab.
https://github.com/topics/clab-topo – Topologies contributed by community
https://github.com/arista-netdevops-community/building-containerlab-with-ceos/tree/main?tab=readme-ov-file – Amazing Repo
https://arista-netdevops-community.github.io/building-containerlab-with-ceos/ -> This presentation has some a eVPN topology and also explain how to spin up a quick eVPN with ceos Continue reading
Network CI/CD Pipeline – GitLab Introduction
Hi all, welcome back to our Network CI/CD blog series. In this part, we’ll discuss what exactly GitLab is and the role it plays in the whole CI/CD process. We’ll explore how to use GitLab as a Git repository, how to install GitLab runners, and how to write a GitLab CI/CD pipeline, among other topics. So let’s get to it.
Prerequisites
Before we proceed, let’s go over some prerequisites. This part of the series assumes you have some familiarity with Git, Ansible, and basic Docker concepts. I’m not an expert in any of these, but I have a basic understanding of what each tool does and how to configure and use them. Even if you’re not very familiar, you can still follow along as we go step by step.
Using GitLab as a Git Repo
Git is a version control system that allows you to track changes to your code, collaborate with others, and manage different versions of your projects. It's a fundamental tool for network automation that works with code or configuration files.
Git for Network Engineers
As Network Engineers, we work with various text files such as network device configurations, scripts, and text-based documentation. Managing these Continue reading
Worth Exploring: Open-Source Network Automation Labs
Urs Baumann loves hands-on teaching and created tons of lab exercises to support his Infrastructure-as-Code automation course.
During the summer, he published some of them in a collection of GitHub repositories and made them work in GitHub Codespaces. An amazing idea well worth exploring!
The Hedge 241: Starlink Performance w/Geoff Huston
When Starlink first went into service we heard a lot of stories about how its Internet service was slow and unreliable. We’re a few years into Starlink launching satellites–how is Starlink holding up? Is service improving? Geoff Huston joins Tom, Eyvonne, and Russ to look into Starlink’s performance today.
TL002: The Philosophical Roots of Leadership
On this episode of Technically Leadership, we talk about the philosophical underpinnings of leadership. We discuss what it means to hold and drive a vision for a technical organization, how to build a strong team culture, handling layoffs and letting people go, and exploring what philosophy can teach us about leadership. Guest Matt Butcher, CEO... Read more »Common Services VRF with EVPN Control Plane
After discovering that some EVPN implementations support multiple transit VNI values in a single VRF, I had to check whether I could implement a common services L3VPN with EVPN.
A common services VPN is a VPN in which server sites can communicate with each other and the clients, but the clients cannot communicate between themselves.
TL&DR: It works (on Arista cEOS)1.
Here are the relevant parts of a netlab lab topology I used in my test (you can find the complete lab topology in netlab-examples GitHub repository):
NAN072: Exploring Internet2’s Network Automation for University and Research Networks
On today’s episode we delve into Internet2’s mission to advance research and education through high-speed connectivity. University and research networks may have more complicated designs, requirements, and restrictions than you’d expect. We talk about these challenges, along with innovative network automation solutions. The discussion emphasizes the collaborative, member-driven approach of Internet2 and its commitment to... Read more »Not All OSPF Inter-area Traffic Traverses Interfaces In Area 0
Everyone knows that OSPF is a link state protocol. Those that study also discover that OSPF behaves like distance vector between areas as Type-1- and Type-2 LSAs are not flooded between areas, but rather summarized in Type-3 LSAs. This means that OSPF is a logical star, or hub with spokes, where Area 0 is the backbone and all other areas must connect to Area 0. This is shown below:
With this topology, since all the areas only connect to the backbone area, traffic between areas must traverse the backbone:
We learn about this behavior in literature where there is a very straight forward topology where each ABR is only attached to one area beyond the backbone. Such a topology is shown below:
In such a topology, traffic between RT04 and RT05 has to traverse the backbone. This is shown below:
However, what if you have a topology which is not as clear cut? Where an ABR attaches to multiple areas? This is what we will explore in this post. We’ll be using the topology below:
In this topology, RT02 and RT03 are ABRs. RT02 is attached to both Area 1 and Area 2 in addition to the backbone, while RT03 Continue reading
PP028: Can SecOps and NetOps Work Together?
IT tends to divide itself by job function and technological specialization, especially as technology gets more complex. However, each IT domain is part of a larger system, and these systems require coordination and cooperation to operate effectively. On today’s Packet Protector we look at how and why Security Operations (SecOps) and Network Operations (NetOps) should... Read more »HS081: What’s Your Strategic Plan for AI Infrastructure?
AI seems to be changing everything, including your IT infrastructure. Do you have a strategic plan for your AI infrastructure? Today we discuss the merits and challenges of cloud computing, on-premises solutions, hybrid models, and edge computing along with the importance of low latency for real-time AI applications and the potential of edge computing in... Read more »
Multivendor EVPN Just Works
Shipping netlab release 1.9.0 included running 36 hours of integration tests, including fifteen VXLAN/EVPN tests covering:
- Bridging multiple VLANs
- Asymmetric IRB, symmetric IRB, central routing, and running OSPF within an IRB VRF.
- Layer-3 only VPN, including routing protocols (OSPF and BGP) between PE-router and CE-routers
- All designs evangelized by the vendors: IBGP+OSPF, EBGP-only (including reusing BGP AS number on leaves), EBGP over the interface (unnumbered) BGP sessions, IBGP-over-EBGP, and EBGP-over-EBGP.
All tests included one or two devices under test and one or more FRR containers1 running EVPN/VXLAN with the devices under test. The results were phenomenal; apart from a few exceptions, everything Just Worked™️.