
For anyone who has managed a data center fiber plant over the past decade, the arrival of 400 Gigabit Ethernet came with a painful side effect: singlemode fiber. If your…
The post 400G Over Multimode Fiber: BiDi Changes the Game appeared first on AboutNetworks.net.
I often need a quick calculation or a unit conversion. Rather than reaching for
a separate tool, a few lines of Zsh configuration turn = into a calculator.
Typing = 660km / (2/3)c * 2 -> ms gives me 6.60457 ms1 without
leaving my terminal, thanks to the Zsh line editor.
The main idea looks simple: define = as an alias to a calculator command. I
prefer Numbat, a scientific calculator that supports unit conversions.
Qalculate is a close second.2 If neither is available, we fall back to
Zsh’s built-in zcalc module.
As the alias built-in uses = as a separator for name and value, we need to
alter the aliases associative array:
if (( $+commands[numbat] )); then aliases[=]='numbat -e' elif (( $+commands[qalc] )); then aliases[=]='qalc' else autoload -Uz zcalc aliases[=]='zcalc -f -e' fi
With this in place, = 847/11 becomes numbat -e 847/11.
The first problem surfaces quickly. Typing = 5 * 3 fails: Zsh expands the *
character as a glob Continue reading
Authors: Alex O’Regan, Aadhil Abdul Majeed
Ever had a load balancer become the bottleneck in an on-prem Kubernetes cluster? You are not alone. Traditional hardware load balancers add cost, create coordination overhead, and can make scaling painful. A Kubernetes-native approach can overcome many of those challenges by pushing load balancing into the cluster data plane. Calico Load Balancer is an eBPF powered Kubernetes-native load balancer that uses consistent hashing (Maglev) and Direct Server Return (DSR) to keep sessions stable while allowing you to scale on-demand.
Below is a developer-focused walkthrough: what problem Calico Load Balancer solves, how Maglev consistent hashing works, the life of a packet with DSR, and a clear configuration workflow you can follow to roll it out.
On-prem clusters often rely on dedicated hardware or proprietary appliances to expose services. That comes with a few persistent problems:
In a traditional hypervisor environment:
Default Kubernetes pod networking works very differently:
This creates a major problem for VM migration:
Welcome to Technology Short Take #192! Who’s interested in some links to data center technology-related articles and posts? If that’s you, you’re in the right place. Here’s hoping you find something useful!
For over three decades, BGP’s AS_SET path segment has been a legal, if problematic, feature of Internet routing. In May 2025, the IETF formally ended that era. RFC 9774 doesn’t merely discourage AS_SET: it prohibits it entirely.
This post unpacks what AS_SET is, why it was created, what went wrong, and what network operators need to do now that the IETF has made its deprecation a binding standard requirement.
Every BGP UPDATE message carries an AS_PATHattribute – a record of the Autonomous Systems a route advertisement has traversed on its way from origin to destination. It serves two critical functions: loop prevention (a router seeing its own AS in the path discards the route) and policy (operators use AS_PATH to make routing decisions based on where traffic comes from or how it’s being forwarded.
The AS_PATH is composed of path segments, each of which is one of four types:
| Type | Description | Status |
|---|---|---|
| AS_SEQUENCE | An ordered list of ASes the route has passed through. The most common and well-understood type. | Valid |
| AS_SET | An unordered set of ASes created during route aggregation. Now deprecated. | Deprecated |
| AS_CONFED_SEQUENCE | Ordered list of Member AS Numbers within a Continue reading |
Most vendors “discovered” anycast gateways when they tried implementing routing between MAC-VRFs in an EVPN environment and hit all the usual tripwires (more about that later). A few exceptions (like Arista) supported them on VLAN segments for over a decade, and it was a no-brainer to extend that support to VXLAN segments.
Want to try out how that works? The Anycast Gateways on VXLAN Segments lab exercise is just what you need.
You can run the lab on your own netlab-enabled infrastructure (more details), but also within a free GitHub Codespace or even on your Apple-silicon Mac (installation, using Arista cEOS container, using VXLAN/EVPN labs).
Despite the wealth of data available, distilling a coherent narrative from a Kubernetes cluster remains a challenge for modern infrastructure teams. Even with powerful visualization tools like the Policy Board, Service Graph, and specialized dashboards, users often find themselves spending significant time piecing together context across different screens. Making good use of this data to secure a cluster or troubleshoot an issue becomes nearly impossible when it requires manually searching across multiple sources to find a single “connecting thread.”
Inevitably, security holes happen, configurations conflict causing outages, and teams scramble to find that needle-in-the-haystack cause of cluster instability. A new approach is needed to understand the complex layers of security and the interconnected relationships among numerous microservices. Observability tools need to not only organize and present data in a coherent manner but proactively help to filter and interpret it, cutting through the noise to get to the heart of an issue. As we discussed in our 2026 outlook on the rise of AI agents, this represents a fundamental shift in Kubernetes management.
Key Insight: With AI Assistant for Calico, observability takes a leap forward, providing a proactive, conversational, and context-aware intelligence layer to extract actionable insights from a Continue reading
We're making Cloudflare the best place for building and deploying agents. But reliable agents aren't built on prompts alone; they require a robust, coordinated infrastructure of underlying primitives.
At Cloudflare, we have been building these primitives for years: Durable Objects for state persistence, Workflows for long running tasks, and Dynamic Workers or Sandbox containers for secure execution. Powerful abstractions like the Agents SDK are designed to help you build agents on top of Cloudflare’s Developer Platform.
But these primitives only provided the execution environment. The agent still needed a model capable of powering it.
Starting today, Workers AI is officially in the big models game. We now offer frontier open-source models on our AI inference platform. We’re starting by releasing Moonshot AI’s Kimi K2.5 model on Workers AI. With a full 256k context window and support for multi-turn tool calling, vision inputs, and structured outputs, the Kimi K2.5 model is excellent for all kinds of agentic tasks. By bringing a frontier-scale model directly into the Cloudflare Developer Platform, we’re making it possible to run the entire agent lifecycle on a single, unified platform.
The heart of an agent is the AI model that powers it, and that Continue reading
Something didn’t feel right as I tried to check whether the IPv4 ECMP I observed in the latest version of Arista cEOS containers works with my MPLS/anycast scenario. The forwarding tables seemed OK, but I wasn’t getting MPLS labels in the ICMP replies (see RFC 4950 for details), even though I know Arista EOS can generate them.
I decided to go down that rabbit hole and built the simplest possible BGP-free core (the addition of BGP will become evident in a few seconds) to investigate PE/P-router behavior:

Lab topology
If you’re running workloads on Amazon EKS, there’s a good chance you already have some form of network observability in place. VPC Flow Logs have been a staple of AWS networking for years, and AWS has since introduced Container Network Observability, a newer set of capabilities built on Amazon CloudWatch Network Flow Monitor, that adds pod-level visibility and a service map directly in the EKS console.
It’s a reasonable assumption that between these tools, you have solid visibility into what’s happening on your cluster’s network. But for teams focused on Kubernetes security and policy enforcement, there’s a significant gap — and it’s not the one you might expect.
In this post, we’ll break down exactly what EKS native observability gives you, where it falls short for security-focused use cases, and what Calico’s observability tools, Goldmane and Whisker, provide that you simply cannot get from AWS alone.
AWS offers two main sources of network observability for EKS clusters:
VPC Flow Logs capture IP traffic at the network interface level across your VPC. For each flow, you get source and destination IP addresses, ports, protocol, and whether traffic was accepted or rejected at Continue reading