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Featured posts

Understanding the Cilium Datapath: How Packets Actually Move Between Pods

I traced every packet path through Cilium's datapath: veth pairs, eBPF hooks, native routing with auto injection, static routes, live BGP with FRR and ECMP, VXLAN encapsulation, and Geneve. Four kind clusters, real tcpdump captures, all from my lab.

12 min read

Designing a RoCEv2 Backend Fabric for a 4,000-GPU B200 Cluster

How to Simulate Multicluster Kubernetes Locally: Regions, Failover, and Cross-Cluster Traffic with Kind.

Designing the Network Fabric for a 4,000-GPU B200 Cluster: A Complete Walkthrough

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Courses

Mastering BGP

Mastering BGP delves into its architectural strengths: reliability (TCP foundation, keepalives), stability (MAI, dampening, route refresh), scalability (reflection, confederations, selective propagation), and flexibility (policy-driven, path attributes, communities).

Mastering IS-IS

IS-IS, a robust link-state routing protocol, is key for scalable networks. This series demystifies IS-IS from its Layer 2 operations, NSAP addressing, and hierarchical design to advanced traffic engineering with practical Juniper configurations. Master IS-IS for high-performance network designs.

Network Automation with GO

Hello and welcome to "Network Automation with Go," a blog series designed for network engineers and developers. We'll explore how Go's speed, concurrency, and simplicity can help you build powerful, efficient, and scalable network automation solutions. Get ready to level up your skills!

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Understanding the Cilium Datapath: How Packets Actually Move Between Pods

12 min read

Designing a RoCEv2 Backend Fabric for a 4,000-GPU B200 Cluster

A practical redesign of a 4,000-GPU B200 cluster using RoCEv2 over Ethernet. This companion dives into lossless fabric engineering, BGP underlay, congestion control, and real-world trade-offs versus InfiniBand at hyperscale.

39 min read

Kubernetes Meets the Data Center: Cilium BGP, FRR Leaf-Spine Fabric, and Role-Based L3/L7 Policy Enforcement

I built a leaf-spine data center fabric, connected it to Kubernetes with Cilium BGP, exposed services through LoadBalancer VIPs, enforced L3/L7 policy, and traced the end-to-end data path with Hubble, from client request to pod response.

16 min read

How to Simulate Multicluster Kubernetes Locally: Regions, Failover, and Cross-Cluster Traffic with Kind.

Step-by-step tutorial for running a multicluster Kubernetes setup locally using Kind. Covers regional LoadBalancer routing, cross-cluster connectivity, failover simulation, and rolling updates across three clusters.

13 min read

How to Train a Private AI That Knows Everything Your Organisation Knows

Your organisation's knowledge is locked in PDFs and documents nobody has time to read. This guide shows you how to train a private AI on that material, run it on your own machine, and query it like a senior expert who never sleeps.

20 min read

Agents in Production Without the Cloud: An AI Agent Stack on Kubernetes

A practical walkthrough of building a sovereign AI agent stack on Kubernetes using open-source tools. Model inference, memory, tooling, and observability run entirely on-premises, keeping prompts, telemetry, and data inside infrastructure without relying on external AI APIs.

15 min read

End-to-End TLS Termination with Kubernetes Ingress

Kubernetes Ingress gives you host-based routing and TLS termination through a single external IP. This walkthrough covers Contour, self-signed certs, and validating HTTPS load balancing on a Kind cluster from scratch.

9 min read

Getting LoadBalancer Services Working in a Kind Cluster.

LoadBalancer services in Kind stay <pending> forever without a cloud controller. Here is how to fix that with cloud-provider-kind, get a real external IP, and actually validate load balancing across your pods.

5 min read

Designing the Network Fabric for a 4,000-GPU B200 Cluster: A Complete Walkthrough

A complete walkthrough of the network fabric design for a 4,000-GPU NVIDIA B200 cluster: 3-tier InfiniBand backend, dedicated Ethernet fabrics for management and storage, OOB network, rail-optimized topology with intra/inter-rail communication patterns, power, cooling, and rack layout.

27 min read

Kubernetes BGP Networking: Cilium VXLAN, FRRouting, and Full-Stack Observability

Cilium VXLAN, FRRouting eBGP, Hubble, and Kubeshark on a 4-node ARM64 cluster. Covers routing limitation, the FRR self-peering problem, and a 52-check validation suite from scratch.

10 min read

Kubernetes CNI Options: A Comprehensive Comparison

Compare the top Kubernetes CNI options: Calico, Cilium, Flannel, Weave, and more. Learn pros, cons, and which one fits your cluster’s performance, security, and scalability needs.

1 min read

Building a Production-Ready Kubernetes Cluster on Ubuntu 24.04 LTS (with Cilium CNI)

Build a production-ready 4-node Kubernetes cluster on Ubuntu 24.04 LTS — from bare VMs to Cilium CNI with Hubble observability. Includes every gotcha we hit so you don't have to.

9 min read

Untangling the AI Traffic Jam: How BGP NNHN and Global Load Balancing Keep GPUs Fed

Is your AI fabric blind? Static ECMP can’t handle Elephant Flows. Learn how BGP NNHN & Global Load Balancing provide the "X-ray vision" needed to stop congestion and maximize your GPU investment.

3 min read

Running BGP Unnumbered with IPv6 Link-Local

BGP Unnumbered uses IPv6 Link-Local addresses for peering, eliminating unique IP assignments on transit links. This simplifies network design. See how to configure this modern approach on Cisco NX-OS and Juniper, enabling one session to carry both IPv4 and IPv6 routes.

5 min read

How SLAAC Builds Your Address

IPv6’s SLAAC lets devices self-configure without DHCP. Hosts send RS, receive RAs (with prefixes/flags), and build their GUA using a unique Interface ID (EUI-64/Privacy). A quick DAD check confirms uniqueness. It’s simple and stateless.

2 min read

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