Category Archives: Networking

Jabbering Transceiver Error Rears Its Ugly Head

My first real networking job was as a Networking Consultant for Excelan in 1988. That company was purchased in 1989 by Novell, where I stayed quite happily until 1994. My initial training for the position included learning a hardware-based protocol analyzer (the LANalyzer, in fact). One of the things we learned in class was a coax-based 802.1 10 Mbps transceiver could crash an entire physical LAN. This device had a classy alias: “vampire tap.”  It was scre-clamped onto a thickwire coax cable to add one or more  network ports. Sometimes, its built-in circuitry would go bananas and overrun the network with bogus traffic. This problem, known as a jabbering transceiver error rears its ugly head recently. It happened  on  one of the Chez Tittel GbE switch domains.

When Jabbering Transceiver Error Rears Its Ugly Head, Divide and Conquer

Here’s a quote from the 2000 classic by Charles Spurgeon: Ethernet: The Definitive Guide

The quote comes courtesy of Google books, pg. 107.
(I still have a hardcopy on my bookshelf).

I’m pretty sure that NICs don’t have transceivers any more, so they aren’t really subject to such failures. But similar behavior — specifically, failure of a switch domain — is well-known to occur when hardware problems bedevil a LAN segment. For a while there, I was chasing random network failures in my office. They would kick all the machines off the switch, but would gradually let everybody back on.

It wasn’t until I quit using the built-in GbE port on my retiring X220 Tablet PC that the problems stopped. I was able to confirm the issue by plugging the RJ-45 cable back into that until and watching the circus start back up. If I switched to a USB dongle instead, the GbE domain attached to either or both switches in my office worked fine. One is a standalone NetGear 8-port GbE switch, the other an 8-port switch integrated into my Asus 802.11AX WAP/router.

Historical Note

Divide and conquer was the recommended troubleshooting method to identify a jabbering transceiver. One would subdivide the cable segment by interrupting it at a repeater, and terminating each sub-segment. Whichever segment stayed broken had the failing device. Repeat until the device can be identified, then replace it. I did this for TRW in Austin in 1988 on an actual service call there…

It wasn’t really until I started the trip down memory lane to my first-ever Ethernet networking class in 1987, and my trip to TRW,  that I understood what was happening. The built-in GbE interface was failing, and acting like a jabbering transceiver. I can’t exactly say “everything old is new again.” But I can say, an old lesson learned came in handy. And indeed, that is the way things sometimes go, shooting trouble here in Windows-World!

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Power Options VM Surprise

It’s been a painful last few days here in Windows World. I’ve been working on a loaner, locked-down machine in connection with a code analysis project. Because that code is protected and valuable intellectual property (IP), I’m able to access its GitHub repository only through a VM running on a hardened and isolated system. Essentially, I have to access the VM through a browser tab set up inside a VPN-accessible secure store. It hasn’t been going too well, either: each time I tried to use the VM and left the machine alone for a while, it would drop its connection. And then, to make things worse, I couldn’t get back in without asking an IT admin to reset the server side of the remote access environment. That’s where  an unwanted and unexepected Power Options VM surprise came into play.

What Is a Power Options VM Surprise?

If you look at the lead-in graphic, you’ll see that one change I make on my Windows PCs post-upgrade or install is to change the sleep interval to “Never.” The default is 30 minutes. Accessing the VM used a commercial VPN into a host server. Then, a remote access client (first RDP, then VNC) connected to the VM itself. For a long time, the firm’s IT guy kept fiddling with RDP settings and such. Eventually he switched to VNC for remote access, thinking it might be an RDP protocol issue at work (or not).

But the disconnect issues kept popping up, where the VM connection would drop when the machine was idle for 30 minutes or more. This finally caused him to investigate the Power Options, where it was immediately obvious the default “sleep after 30 minutes” was the culprit. Resetting the value to my usual preference — that is “Never” — has since fixed things, hopefully for good.

Troubleshooting 101: Don’t Overlook the Obvious

As an outsider with only a regular user account, it wasn’t up to me to mess with default settings on the locked-down machine furnished to me for this project. Ditto for default settings for the VM I was accessing to get into the target code base. But gosh: I have to believe we were looking for complex solutions to a seemingly complex problem. Instead, we should have been looking for simple solutions for a straightforward default settings check.

The moral of this story is not lost on me. I hope it will likewise inspire you to make a checklist when working with VMs, and to put “check default settings” (especially in Power Options) right near the head of that list. Sleep may “knit up the raveled sleeve of care,” as the Immortal Bard put it. But sleep causes all kinds of interesting problems for Windows PC — and now I know, for Windows VMs, too. Funny thing, I’ve learned to make this tweak because I use RDP extensively here at Chez Tittel to get from my production desktop to the 10-plus other PCs usually running around here. I shoulda known…

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NirSoft Adds Winning ManageWirelessNetworks Tool

Anybody who’s been reading my stuff for a while knows I like the work of Israeli developer Nir Sofer. His company, NirSoft adds winning ManageWirelessNetworks tool to its lineup.  If you take a look at the lead-in graphic above, you can see some of my traveling history enshrined in the profile names in the left-hand column. There, you’ll see names for hotels, law firms, and more amidst that list.

If NirSoft Adds Winning ManageWirelessNetworks Tool, Use It!

Many — nay, most — of the names in that list I will never need or use again.  If you choose “Run as Administrator…” when you launch this tool, you can select obsolete or unneeded profiles in the UI. (Ctrl-click works to select multiple individual items; Shift-click works for ranges.) If you then click the red X in the icon bar above, they’ll all be deleted.

Here’s what my current list of active, valid Profile Names looks like after pruning, in fact:

NirSoft Adds Winning ManageWirelessNetworks Tool.cleaned

After clean-up, the item count in the list drops from 26 to 6. Easily done, too!

Sure, you can remove stale entries for Wi-Fi networks at the command line. I wrote a post about this for the TechTarget incarnation of this blog back in 2017 “Clean Up Old Wireless Profiles in Windows 10.” But the NirSoft tool beats that method cold: it’s visual, lets you handle all stale entries in one go, and works like a champ. I’d long wondered why the NirSoft collection didn’t have such a tool already. Well now it does: and I’m glad!

As the old advertisement said: “Try it, you’ll like it!” I did, and I do. You can do likewise.

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Resenting Mobile-Only Network UIs

In the process of troubleshooting the LAN here at the Tittel household recently, I replaced a Gen 1 Router/Switch/WAP device with its Gen 2 counterpart. Spectrum provides that equipment for something like $7 a month. I don’t resent that charge. But what has me considering a switch to my own equipment is resenting mobile-only network UIs now forced upon me.

What does that mean? It means I can’t log into the gateway’s TCP/IP address in a Web browser any more to access and manage setup and configuration. No! I must now use the MySpectrum app on a cellphone instead. That’s a problem for all kinds of reasons, some good ones, and some that may sound whiny. Apologies in advance.

Why I’m Resenting Mobile-Only Network UIs

Because I MUST run the device UI through a smartphone app, I’m limited to its tiny screen, virtual touch keyboard, and limited silicon. Basically, that means my 100 wpm typing speed on a keyboard falls off  a cliff when I switch to a screen-based layout. This gives my facility and productivity a massive knock, and earns my displeasure.

And alas, I’m no spring chicken anymore either. At 68, I am already in the habit of viewing web pages at 125% magnification to make things easier on my eyeballs. I’ve been known to bump that to 150% or higher when faced with lots of fine print. Forcing me onto a 750×1334 screen goes against my preferences, and hurts my eyes.

And then there are the UI exigencies that small screens dictate. I checked, and I have to work through 7 screens to reserve an IP address within the new app. It used to be a lot faster and easier under the old, Web-based UI. Sigh.

Now that my rant is ended, I’d like to remind Spectrum that good customer service is about providing accessible alternatives. C’mon guys: if a late middle-aged, early geriatric has mild usability issues, what about others with more severe access or vision impediments? Is a cellphone-only approach really workable for everybody?

Exploring Technology Alternatives

I won’t let this slow me down too much. First, I plan to see if I can get MySpectrum to run on my iPad. I do have a Bluetooth keyboard for that device, and can put it to work for configuration jobs. I also see that long-time high-value remote access app TeamViewer lets users run a cellphone app from a PC desktop. That’s not the usual path for remote access between such devices, but it might be just what I need.

Stay tuned. Once my current fit of pique subsides, I may find some kind of workable alternative or usage scenario. If I do, I’ll report back with more info.

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More Networking Trouble Manifests

Wouldn’t you know it? Today’s a busy day here at Chez Tittel. I’ve got multiple deliverables due, and it’s my son’s “A day” at school (8 classes, several of them challenging). “The Boss” needs her Internet access, too, for purposes both commercial and personal.  That’s no doubt why today, of all days, more networking trouble manifests here and now. For as long as two hours we had no access at all.

When More Networking Trouble Manifests, Then What?

Yesterday, I was inclined to blame my aging desktop when only its NIC stopped working. Today, we lost not just all of the wired connections, but wireless was popping in and out, too. Suddenly things were much clearer: the combination WAP/router from Spectrum was failing — or flailing — intermittently.

A quick call to tech support confirmed that (a) I have a first-gen WAP/router device for the company’s 1 Gbe service and (b) such behavior  happens often enough for team members to know about it. My friendly support guy “Jeff” suggested I drive over to the nearest Spectrum offices and trade in the current unit for a new one.

In the Land of the Blind…

Fortunately, the nearest such office is less than 15 minutes from the house. So I packed up the WAP/router, jumped in the car, drove over and swapped it for a replacement device. Surprise! It’s got a 2.5 GbE interface between cable modem and WAP/router, which I supposed is all to the good.

Even more fortunately, it proved to be (mostly) a matter of plug-and-play upon installing the new device. I did have to reboot the cable modem to get it to recognize and talk to the WAP/router (by getting its MAC address table updated, I assume). I will have to do some clean-up work (static IP assignments for my networked printers) later.

But for now, things are working more or less as they should be. I’m keeping my fingers crossed that they’ll stay that way. I’ve learned now that a failing switch can make NIC drivers go wonky, and have added to my store of troubleshooting lore and experience.

And that’s the way things go sometimes, here in Windows-World! Sigh.

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GbE Adapter Driver Goes MIA

I had an interesting if unwanted surprise waiting for me when I returned to my production PC after taking a break this morning. Instead of my usual Internet connection, I had zilch. Domain names weren’t resolving. Running IPCONFIG I saw an APIPA address (starts with 169.x.x.x). I knew this meant my NIC had lost its connection with the primary network router, from whence DNS, DHCP and Internet access come. Upon checking the driver in Device Manager, I saw these dreaded words “No drivers are installed for this device” (see above). Indeed when a GbE adapter driver goes MIA, there isn’t much you can do with that device until the driver gets fixed.

If GbE Adapter Driver Goes MIA, Then What?

Fortunately my Asrock Extreme 7+ has two GbE adapters: an Intel I211 and an Intel I219-V. It was the I219-V that dropped off the network. But when I plugged in the I211, it immediately resumed operation. My suspicion: driver corruption in the I219-V driver. So I visited the Intel download site and grabbed a copy of the 26_2.zip Intel Ethernet Adapter Complete Driver Pack.

But then, things got interesting. The same thing that happened with the I219-V started up with the I211. It wasn’t until I reinstalled a new driver from the Intel pack linked above that the I219-V returned to normal operation. I ran DISM /checkhealth with nothing found, but SFC /scannow did report making some repairs. Something odd has definitely hit my production networking facilities.

Bracing for the Inevitable…

I’ve been pondering a new desktop PC build for some time now. This rig is built around an Asrock Extreme7+ and an i7-6700 Skylake processor . Both made their debut in Autumn 2015 (the chip in September, the board in November). As I recall I built this system in the Spring of 2016. That’s now more than 5 years ago. I’m inclined to think this may be fate’s way of telling me it’s time to replace my desktop. Time to revisit and revise my build plans, and get on the stick.

Note Added May 7 (One Day Later)

Today, the whole network here at Chez Tittel blew up. Weird wireless and wired LAN behavior convinced me the Spectrum-supplied WAP/Router/switch device was losing … something. A quick trip to the Spectrum store and a device swap set things right. Read all about it here: More Network Trouble Manifests.

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Pondering Amazon Fire HD vs. iPad

Today’s disquisition is a bit off the beaten track and brings Windows 10 to bear only tangentially. My family is in the market for another tablet, primarily for reading and media consumption. I’ve already owned an iPad 2 (now retired) and currently own an iPad Air 2 (2014 vintage). You’d think I’d buy another iPad, right? But the model I want (iPad Air, 256 GB, cellular) costs a whopping US$879 at the Apple Store right now. And then, there’s a new generation of Fire HD tablets about to arrive, at less than half that cost. By the time I add in a cover and keyboard, it’s more like a 2.5:1 cost ratio. Frankly, that’s what has me pondering Amazon Fire HD vs. iPad.

Price Provokes Pondering Amazon Fire HD vs. iPad

On the plus side, the iPad offers more power, lighter weight, and higher screen readability. On the minus side, it ends up costing $700 more for more or less the same capability, most of the time. At 12 hours versus 10 hours of battery life, the Amazon Fire HD comes out ahead on untethered operation, too. Then too, the Fire HD Plus Pack costs under US$300. The device even accommodates a MicroSD card for added storage capability (which the iPad does not, though you can attach storage through its input port, using a special US$13 to 20 adapter).

What’s fascinating to me, though, is the front-and-center add-in on the Fire HD of a Microsoft 365 subscription. Though it means you can use the unit for web-based Office right away, I’m also convinced it will be usable as a Cloud PC client (as will the iPad also, no doubt) when that comes out later this year. Thus, either platform will serve as a “thin client” for my Windows 10 stuff sooner or later.

To me that raises the very real question of why I should spend 333% more to get an iPad? Shoot, it looks like Fire HD can do most of what I need for substantially less. For a lot of people, I’m thinking that’s exactly what Amazon wants. I may just try it, and see what happens!

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Thunderbolt 4 Is Getting Underway

OK, then: first things first. Thunderbolt is a joint technology effort from Intel and Apple. The first iteration appeared in 2011, and version 4 (aka Thunderbolt 4) is just showing up in the marketplace. Intel’s 11th gen processors and supporting motherboards are the first to provide native Thunderbolt 4. And of course, add-on PCIe cards for Thunderbolt 4 are also starting to trickle out (see this ASUS item, for example). Hence the assertion that heads this story: Thunderbolt 4 is getting underway.

I’ve had recent experience to show me that the speed advantages it can confer are measurable and tangible. At the same time, I’ve learned that the right cables can — and do — make huge differences.

What Thunderbolt 4 Is Getting Underway Really Means

The following table sums up the differences among Thunderbolt 3 and 4, and USB 3 and 4 versions. Basically, it offers more and faster capabilities, but is limited to special, certified cables no more than 2M in length. It can also handle either 2 4K displays or 1 8K display, and works with the latest PCIe 32Gbps lanes. It is, in fact, a pretty strong argument for all-around hardware upgrades (mobo and ports, cables, and peripherals) all by itself. Check the table for details, please.

. Thunderbolt 4 Thunderbolt 3 USB4 USB 3/DP
1 universal port
40Gb/s cables up to 2 meters
Accessories with up to 4 TB ports
Min PC speed requirement 40Gb/s 40Gb/s 20Gb/s
(40Gb/s is optional)
10Gb/s
MinPC video requirement 2 x 4K displays
or
1. x 8K display
1 x 4K display 1` display (no min resolution) 1 display (no min resolution)
Min PC data requirements PCIe 32Gb/s
USB.3.2 10Gb/s
PCIe 16Gb/s
USB 3.2 10Gb/s
USB.3.2 10Gb/s USB 3.2 5Gb/s
PC charging port required At least one
PC wake from sleep w/TB dock connected Required
MinPC port power for accessories 15W 15W 7.5W 4.5W
Thunderbolt networking
Mandatory certification for PCs and accessories
Intel VT-d based DMA protection required
USB4 specification Compliant Compatible Compliant Compatible
Source: Table from 11/20/2020 Liliputing story about Thunderbolt and USB versions.

What I Plan To Do About Thunderbolt 4

I’ve got a new PC build in my relatively near future (as soon as finances allow). I’ll be making sure to pick motherboard and CPU with Thunderbolt 4 support. I’m looking around right now and while some cases do offer USB-C support, none of them have caught up to Thunderbolt 4 capability just yet. I may end up waiting for that to occur, and go ahead and recycle the trusty old Antec 902 case I recently reclaimed from my sister. This may take some further thought and research. Stay tuned!

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Samsung Network Printer Goes Missing

OK, I admit it. I hadn’t set up DHCP reservations on my LAN. I could try to blame the Spectrum-supplied router that provides DHCP, but it’s really my fault. Thus, when I saw my Samsung ML-2581ND laser printer was offline yesterday morning, I immediately knew what was up. Generally, when the Samsung Network Printer goes missing on my LAN it’s because DHCP has assigned it a different IP address.

Look at the lead-in graphic for this story. There you’ll see that the device (Samsung ML-2850) is associated to Private IP 192.168.1.126. It had previously been …127. And as soon as I changed that address selection on the Ports tab of Printer Properties, it started working again. So how did I figure out which port it had actually been assigned?

When Samsung Network Printer Goes Missing, Then What?

That’s when I call on one of Nir Sofer’s handy network utilities — namely NetBScanner. It quickly scans the local cable segment on its address range. In fact, the program is smart enough to figure that out on its own, after which it supplies a short list of all occupied addresses in that range. Here’s what I saw when I scanned my local wired Ethernet:

Samsung Network Printer Goes Missing.NetBscan-results

Notice the entry for …126 which also shows the device name SAMSUNGNWP. That’s what I want!

It turns out I already had defined this address in the Ports tab, so all I had to do was switch the device from the now-incorrect …127 entry to the current …126 entry and it was done. That meant unchecking the box next to the former, and checking the box next to the latter. Dead simple, quick and easy to fix. As long as you know how, that is…

The Right Fix is a DHCP Reservation

DHCP lets admins make static address assignments from the IP address pool it manages. That way, devices like servers and printers can keep the same address forever, and DHCP won’t move those assignments around, as it otherwise might. That shows up under the Advanced and DHCP tabs on my Askey RAC2V1K boundary device. I reserved the …126 address for the Samsung ML-2850 and also the …15 address for my Dell Color Laser CB745E. The latter is shown here:

Samsung Network Printer Goes Missing.DellCPres

By supplying the MAC address and the desired (reserved) IP address, you tell DHCP “hands off” for future assignments.
[Click image for full-sized view.]

So now, I’ve done what I should have done long ago, thanks to sharing my (prior) shame with you, dear readers. Live and learn!

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Untangling Cascading Troubles Gets Frustrating

I’ve been trying to untangle a weird mix of networking and telephony issues going on three days now. As I write this item, in fact, I’m texting with a Verizon tech support person. He’s trying to unsnarl a mix-up around a new 5G MiFi hotspot  I purchased recently. When the device was set up, it was mistakenly tied to my son’s cellphone number. Then, the tech support people tried to switch things around. Alas, they exceeded the allowable number of reset attempts. This requires a 24 hour wait before a retry is allowed. The 24 hours are up, and I’m trying again. Does this explain why untangling cascading troubles gets frustrating?

How Untangling Cascading Troubles Gets Frustrating

Let me count the ways.

  1. Verizon Tech Coaches can’t call my cellphone. It doesn’t ring because of a setting that’s available only in iOS 13 or higher. My iPhone is running 12.5. So I had to work through amazing contortions to get them to call my landline.
  2. The MiFi device hadn’t been working properly. Thus, I wasn’t able to activate it myself. First I learned how to pop the back off the device. Then, I did the old “paper clip in the recessed reset switch” routine to return it to factory settings. After that the UI worked just fine.
  3. As an iOS guy I found myself messing with Gregory’s Android OnePlus 7 Pro. This had me remembering and relearning all kinds of interesting stuff. I’m now more familiar with its UI, device settings and config data . I also now remember what’s up with ICCID and IMEI identifiers.
  4. When my tech support person tried to reset the accounts properly, the provisioning software let him make the changes, then came back and told him “transaction disallowed.” He’s now roping higher level support team members in to reset database rules to make this happen.
  5. The way I got into this snafu to begin with is that my Spectrum Internet connection won’t pass Remote Desktop Protocol through its firewall. When I attempted the necessary port forwarding operations, the device proved unable or unwilling to read the external (WAN or rather cable side) IP address, even though I can see it just fine (and Ping it) from my LAN PC. That led me to say “I can use my MiFi 5G hotspot instead” and started me down the rabbit hole.

So here we are solving problems we didn’t know we had, and dealing with mixups based on pure human frailty.

Tech Support Needs Unified Communications, Badly!

The most amazing thing I’ve learned is that at least two separate tech support operations at Verizon are inappropriately silo’ed. Their Tech Coach operation cannot place voice calls. They are restricted to online chat only. I made the mistake of initiating contact with them on my cellphone, and they couldn’t easily switch over to a PC session, either. I did figure out how to make that happen later on, though so online via cell and via PC do have some integration.

But their app is limited to calling only registered Verizon devices. So when I tried to have them call my cell early on for a voice session, I found myself in a Catch-22. I wanted them to call me, they called me, but my only acceptable target device wouldn’t allow that call to ring in (that’s the iOS setting for version 13 and up, which is turned on and immutable for 12 and under versions and so can’t be accessed or changed on my aging iPhone 6).

At this point it’s taken me over 7 hours to solve a set of problems that are only tangential to the real problem I want to solve with accessing a public IP using Remote Desktop. I’ll get to that and another series of tech support calls with Spectrum next week.

Take a Deep Breath, and Keep Waiting

But I’m learning how to keep calm and carry on in the face of massive frustration. I suppose I should be glad that I’m not the human responsible for the error that triggered this cascade. Lord knows I have been the guilty party often enough myself to write about it regularly in this very blog!

But Wait: There’s More

Yesterday when I wanted to blog about this situation, my ISP’s behind-the-scenes MySQL WordPress server went down. Thus, I was unable to access or post anything until that got fixed. The error cascade is apparently catching, so perhaps you shouldn’t have read this far. Brace yourself!

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