from the net: Overview of Single-Mode and Multimode Fiber Optics

The article compares single-mode and multimode fiber optic cables, especially in how their core design, light propagation, and use-cases differ. Single-mode fiber has a very small core diameter (8-10 microns) and uses lasers or highly focused light sources so that only one light mode travels through at a time. This greatly reduces signal dispersion, permitting high bandwidth over long distances, with low loss—ideal for telecom backbones, submarine cables, and large-scale data center links. On the other hand, multimode fiber has a larger core (50-62.5 microns), allowing multiple light modes to travel simultaneously. It typically uses LEDs, has more signal dispersion, and is more suited to short-distance links (e.g. within buildings, campuses) because its performance degrades over longer spans.

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The Screws of Doom – A DIY Network Horror Story

 

You know those little plastic wall plugs and microscopic screws that sometimes come bundled with network equipment? Yeah, the ones that look like they were designed for a dollhouse renovation. The moment you open the box, you already know they’re useless. The screws are made of some kind of metallic Play-Doh, and the plugs seem engineered to crumble into confetti the second they touch drywall. But hey, the manufacturer included them, so clearly they’re supposed to be "good enough," right? Spoiler alert: they are not.

I recently tried to humor a client by using a set while mounting a small switch, and it felt less like DIY and more like an exercise in emotional resilience. The plug disintegrated halfway into the wall like a vampire caught in sunlight, while the screw—despite my most delicate screwdriver finesse—instantly stripped itself into a sad, shiny cylinder. At one point, I  considered using my teeth to turn the screw since it seems to be made of cheese. The only thing holding that switch in place was my pride, some lint, blood and a questionable amount of wishful thinking.

In the end, I abandoned the "official" hardware and dug through my stash of real screws, the kind forged from actual metal and not leftover tinfoil from someone’s lunch. The switch is now securely mounted, but I kept the original screws and plugs as a reminder. Not as backup hardware—oh no. They sit in a little jar on my desk, a tiny monument to frustration. Every time I see them, I smile and think: "At least I’m not trying to use those today."

And don't get me started on those patch cables you get with some equipment..

From the net: How WiFi Connection Works

 

WiFi Connection

To understand how WiFi clients connect to a network, we need to familiarize with two key processes. The first one is WPA supplicant, where WPA stands for ‘WiFi Protected Access’. The second one is the DHCP client, in which DHCP stands for ‘Dynamic Host Configuration Protocol’.

To illustrate how wifi connection works, the article will cover the following topics:

• 
  
• Intro to Wi-Fi Networks
• 802.11 Authentication and Association
• The 4-way Handshake Phase
• WPA Supplicant
• Getting a DHCP address via D-O-R-A
• DHCP logs
• Wi-Fi monitoring with NetBeez

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Free webcast: Cybersecurity. Seeing is Securing: Building Network Asset Awareness

 except from Brighttalk registration page ..  Click on the image to register

Cybersecurity. Seeing is Securing: Building Network Asset Awareness

Sep 24 2025, 12:00pm EDT

Duration: 60 mins

Presented by Jennifer Minella - Viszen Security

About this talk

You can’t protect what you can’t see—and in most environments, critical assets are hiding in plain sight. This webinar dives into how network visibility is the foundation for stronger control, smarter security decisions, and better collaboration between NetOps and SecOps. We’ll show you how infrastructure asset awareness plays a key role in Zero Trust, compliance, and incident response—and share real-world tips to reduce blind spots using tools you already have. Whether you’re locking down your environment or just trying to get a handle on what’s out there, this session will help you move from guesswork to clarity. In this webinar, you’ll learn: 1. Why Visibility Comes First How asset awareness underpins Zero Trust, compliance, and incident response. Common visibility gaps in hybrid, multi-vendor, and IoT-heavy environments. 2. Bridging NetOps and SecOps Through Shared Visibility Speaking a common “asset language” to align priorities. Using visibility to reduce friction between operational stability and security posture.............

Blast from the past : The Hewlett Packard HP 1611A (1977): A Digital Logic Analyzer Ahead of Its Time

 

In 1977, Hewlett Packard introduced the HP 1611A, a compact and innovative digital logic analyzer designed for engineers working with the rapidly growing field of microprocessors and digital systems. At a time when computers were shifting from large, room-filling machines to smaller, board-level designs, the HP 1611A gave designers a way to capture, view, and troubleshoot digital signals with speed and precision. With 16 data channels and the ability to trigger on specific logic conditions, it was an essential tool for debugging complex digital circuits that oscilloscopes alone couldn’t handle.

The HP 1611A stood out for its portability and ease of use. Unlike many bulky test instruments of the era, this model was relatively lightweight and featured a front-panel interface with straightforward controls. Engineers could directly connect to circuit boards and observe timing relationships between multiple signals at once. This functionality was critical for diagnosing race conditions, bus conflicts, and other subtle timing issues that were increasingly common in microprocessor-based designs of the late 1970s.

Beyond its technical capabilities, the HP 1611A reflects Hewlett Packard’s reputation for engineering excellence. It represented a bridge between traditional analog test equipment and the emerging need for digital analysis tools. Today, collectors and vintage computing enthusiasts see the 1611A not only as a piece of test gear but also as a historical artifact from the dawn of the personal computing era. Its design highlights how HP anticipated the needs of engineers navigating the digital revolution, making the HP 1611A a landmark instrument in the history of electronics.

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When the Camera Isn’t the Problem: How Bad Cabling Fooled Everyone

 It’s easy to assume that when a security camera starts acting up—dropping frames, cutting out, or losing connection—the issue must lie with the camera, NVR hard drives. After all, that’s the most visible part of the system and often the first thing people think to troubleshoot is the camera. But sometimes the real culprit is hidden in plain sight, and in this case, the true problem wasn’t the camera at all.

During this particular troubleshooting session, every finger pointed at the camera: firmware, configuration, even the NVR. Hours were spent trying to reset, reconfigure, and replace software settings, but the issue kept coming back. It wasn’t until I stepped back and checked the basics that the real problem revealed itself—bad cabling. Things started to make a bit more sense when I took a closer look at the video footage and noticed there were gaps of missing time and a lot of flags stating recording is not possible due to degraded communications.

This experience is a reminder that before diving deep into complicated fixes, it’s always worth verifying the foundation. Proper cabling and termination are critical for consistent performance, especially with networked devices like IP cameras. The lesson here: don’t overlook the simplest possibilities. Sometimes the quickest path to a solution starts with checking the cables that connect everything together.

Why You Should Double-Check an Electrician’s Network Cabling Work

 

When it comes to network cabling, never assume that a job is done correctly just because it "looks" complete. In this video, I demonstrate how easily mistakes can slip through even on seemingly functional ports. I show two active network ports that are live and passing traffic—but strangely, I can’t trace them back to any label or position on the patch panel. This kind of oversight might not break your network immediately, but it creates confusion and delays when future troubleshooting or upgrades are needed.

Even more concerning, I uncover a wall jack that was not punched down properly. At first glance, everything appeared fine, but a closer inspection revealed a poor termination that have resulted in connectivity issues. These errors are often overlooked when electricians—who may not specialize in data networking—handle the cabling. Their focus may be on routing and installing cable, not on validating terminations or ensuring end-to-end continuity.

That’s why it’s critical to verify all cabling work after the electrician finishes. Use tools like a cable tester or certifier, map each port to the patch panel, and inspect each termination. I’ve been asking for photos, a video call and walk thru. Don’t wait for problems to arise down the road—check it while access is still easy and expectations are fresh. A few minutes of validation today can save hours of troubleshooting tomorrow.

My Best Friend - Paul W. Smith

 

You’ve probably never heard of Justin Tayler.  If you have, you may be part of his inner circle of friends.  Social media platform Facebook has a 5,000 friend limit, and Justin is renowned for having reached it.  Why the limit?  Facebook claims it’s  “...to ensure manageable connections and interactions.” I’m guessing Justin must spend a lot of time “managing” 5,000 friends

.

Facebook is exploiting the fact that humans instinctively seek connection.  Although romantic love is highly valued in our culture, one of the main reasons we seek therapy is because romantic relationships can be messy.  Romance aside, the value of friendships, in work as in life, should not be overlooked.  Psychologists agree that dependable, healthy friendships are a critical piece of our well-being and longevity.  Even minimal social interactions, research suggests, can be powerful.

There’s more to friends than just unwinding after work at Happy Hour.  Studies show that wrapping up a difficult task with a friend alongside is less stressful than working alone.  Accompanied by a friend, we tend to assess hills as being a little less steep, problems a bit less daunting.  Making friends at work is a good career move.

Much of the research on friends is directed at older adults, who are particularly at risk of social isolation as they retire and begin to scale down their activities.  The American Heart Association has gone so far as to add shared meals, regular social outings and supportive relationships to its established wellness list comprised of healthy diet and weight, exercise, not smoking, controlling stress and getting plenty of sleep.  We know what to do to live long and well.

Except that even before the COVID-19 pandemic forced us all into isolation, we were already becoming lonelier - in the two decades following 1990, the number of adults with no close friends increased from 3% to 12%.   Since that time, as smartphones and social media burst into the culture, social disconnect has risen across all age groups.  The pre-pandemic normal we talk about returning to wasn’t all that great to begin with.

While seniors strive to make friends, increase their joy and leave a legacy, young adults are dealing with existential issues like systemic stress, significant life changes and developmental challenges - basically “Who am I and what am I doing here”?  The support of friends is critical for navigating this treacherous path.  Psychologists recommend promoting platonic social connection in all aspects of our society - school, work, public transportation - pretty much everywhere we encounter others.

Human desires, needs and interests are shifting and unpredictable - we are emotionally untidy beings.  Along with connection, we also crave peer approval, an elusive goal.  As important as they are, IRL relationships with other humans are challenging.  But what if your best friend isn’t human?

Young people spend a lot of time online anyway, so it’s only natural that many have turned to AI chatbots for companionship.  Common Sense Media reports that 72% of surveyed youths have connected with AI companions, and 33% have established relationships or friendships with these chatbots.   Adolescents are naturally drawn to sexuality and romance, and who wouldn’t be attracted to the nearest screen with a hot girl/boyfriend who shows an interest in you and is always available to chat and bond. 

Today’s young people are technically savvy - surely they know that these chatbots are merely algorithms programmed to respond in certain ways to the inputs they receive.  And yet when Stanford University researchers studied students who use the popular AI app Replika, they found that 81% felt that it had intelligence, and 90% found it to be human-like.  Three percent of users felt that the app was directly responsible for guiding them away from suicide.  In a broader sense, chatbots provide troubled teens with practice in developing social skills that will hopefully lead to better IRL’s.

Much of the current debate surrounding AI’s involves random inaccuracies and biases. AI chatbots have the same issues, and many are “free” - a red flag for any online app.  Chatbots can be a privacy nightmare and may encourage harmful behaviors.  The Center for Countering Digital Hate has tested the guardrails for AI chatbots, finding them completely inadequate. Some users received information on contacting a crisis hotline, while others were able to get advice on how to conceal eating disorders, get drunk and high, or draft a suicide letter.  Often safeguards could be circumvented merely by saying that the information was for a presentation, a ruse unlikely to fool a human friend.    Resistance is futile - the AI train has already left the station.  At this point, all we can do is try and keep it on the rails.

The widespread emotional dependence on AI chatbots was brought to light recently when OpenAI upgraded its leading-edge product ChatGPT.  Compared with the previous ChatGPT-4, the new ChatGPT-5 seemed so cold and unemotional that people barely recognized their digital friend. Those with AI “girl/boyfriends” said they felt as if they had lost a loved one.  Online forums like “MyBoyfriendIsAI” and “SoulmateAI” reflected users distress over the change in their digital companions personalities. Even people without emotional attachments to the chatbot said the new version seemed curt and boring.

Our digital life has changed.  Writer Cathy Hackl suggests in a recent Forbes article that we are shifting from the attention economy to the intimacy economy.  If Googling a question online feels empowering, imagine what asking a question of a trusted friend - one who happens to be non-human - will be like in the future.

Maybe this is how you manage 5,000 friends.

 

 Author Profile - Paul W. Smith - leader, educator, technologist, writer - has a lifelong interest in the countless ways that technology changes the course of our journey through life.  In addition to being a regular contributor to NetworkDataPedia, he maintains the website Technology for the Journey and occasionally writes for Blogcritics.  Paul has over 50 years of experience in research and advanced development for companies ranging from small startups to industry leaders.  His other passion is teaching - he is a former Adjunct Professor of Mechanical Engineering at the Colorado School of Mines. Paul holds a doctorate in Applied Mechanics from the California Institute of Technology, as well as Bachelor’s and Master’s Degrees in Mechanical Engineering from the University of California, Santa Barbara.

 

Lost in Translation: A Tale of a Tricky VLAN Mismatch

 

A long time client and online friend reached out with an interesting scenario.

A consultant installed a switch and they were having issues getting it to 'get along' with the existing switches. The consultants opinion was that the current equipment was too 'old' and probably 'not compatible'. the easiest solution was to replace the dozen or so old' switches to the same make and model to ensure compatibility.

He told me that "this recommendation reminds me of spring time in the country running the spreader" ,  lol.  in other words, he didn't believe the consultant.

i explained that unfortunately my calendar is packed at the moment but he could send the logs from the 2 switches they were trying to interconnect, i would take a peek.  i received the logs and called him and asked if he looked at the logs?  He responded "no, why?"  i asked him to look at the logs from his old switch and I'll wait.

Man, oh man, was he mad!!!  After letting him vent for a minute or two, I calmly asked him why he, or his team, didn't look at the logs. He said that the consultant said he already looked at them and there was nothing there.  Woops...  A screen shot of the log is below and i'm sure you can figure out what the issue is.  one side was vlan 172 nd the other was 99.  A simple config change the they were up and running...

Moral of the story is that it doesn't take much to validate what you are being told. Most times you will find that its a quick process and fairly anticlimactic.  But the odd time you will spot something others have missed or possibly learn something. Either way its a win-win in my book..

Why a Handheld Tester Like the NetAlly LinkRunner is Essential

 Quick disclaimer: I don't work for, resell, nor have I been paid by NetAlly for this write up.

When you're faced with an intermittent or underperforming network connection, guesswork is the enemy of efficiency. Having a handheld tester like the NetAlly LinkRunner in your toolkit turns confusion into clarity. In a recent real-world scenario, I used my LinkRunner to uncover a frustrating issue: a router port that refused to negotiate a 1 Gb connection, consistently falling back to 100 Mb—even though everything else in the chain seemed fine.

click on the image if you want an idea of cost , contact you local Netally rep for your pricing

This kind of problem can easily be misdiagnosed without the right tool. Swapping cables, replacing switches, or even blaming end devices wastes time and resources. But with the LinkRunner, I was able to methodically test each component—cable integrity, switch port performance, and router port negotiation. Everything checked out except the one router port, confirming it was the bottleneck. Without the tester, the root cause might have gone unnoticed or been chalked up to general “network flakiness.”

The value of a handheld tester isn’t just in speed—it’s in confidence. Knowing you can isolate faults with precision gives you the upper hand in both troubleshooting and validating new installations. Whether you’re an IT pro or a field technician, tools like the NetAlly LinkRunner are game changers when it comes to making informed, data-driven decisions in the field.

Now I just need to figure out what the LinkRunner error means  😉