Author Archives: Zakaria El Intissar

HSR operates entirely at Layer 2. It doesn’t add a new protocol on top of Ethernet — it inserts a six-byte tag into every frame before it enters the ring. That tag is how nodes identify duplicates, track which path a frame took, and know when to remove a frame from the ring. Understanding the tag structure is… Read More: HSR Frame Structure — How the HSR Tag Works »

very DANH on an HSR ring operates in one of six defined modes. They control how the node handles frame forwarding, tagging, and traffic removal. One is mandatory. The rest are optional. If you’re commissioning, testing, or troubleshooting an HSR network, knowing what each mode does — and what it breaks when misapplied — matters. The Short Version… Read More: HSR Node Modes Explained: H, N, T, M, U and… »

Zero-recovery-time redundancy is one thing. Getting your clocks right across that redundant network is another. In substation automation and industrial control, time synchronization isn’t optional — protection functions, event logging, and sampled value streams all depend on it. This article explains how PTP works specifically in PRP and HSR environments, what the standard requires, and where the practical… Read More: PTP Clock Synchronization in PRP and HSR Networks »

HSR gives you zero recovery time. That part is guaranteed by the protocol. What’s not guaranteed — and what the standard deliberately leaves to implementation — is how much latency each node adds to the ring. That accumulates. Get the ring sizing wrong and you can end up with end-to-end delays that cause problems for time-sensitive applications, even… Read More: How HSR Ring Sizing Affects Latency »

PRP and HSR both deliver zero-recovery-time redundancy — but they work differently, and mixing them takes more than just plugging cables together. This guide walks through every connection scenario defined in IEC 62439-3, what device you need for each one, and what to watch out for when you’re laying out the topology. Before You Start: Know What You’re… Read More: How to Connect PRP and HSR Networks | Step-by-Step Guide… »

If you’re working with PRP or HSR networks, you’ll run into the RedBox and QuadBox. They solve two different problems: the RedBox gets non-redundant devices onto a redundant network; the QuadBox ties two HSR rings together. This article breaks down how each one works, what the standard actually specifies, and where the two are commonly confused. RedBox: The… Read More: RedBox and QuadBox in PRP/HSR Networks »