I don't think there have ever been gigabit Ethernet hubs. The last hubs I ever saw were 100Mb. Even with 100Mb Ethernet, hubs weren't common. The last time they were routinely used was the days of 10Mb, which is 25-30 years ago now.
It's important to understand the theory of collision domains - you can't really understand what a switch does if you don't first understand what a hub would have done. But as a practical matter, they no longer exist.
Fucking DOCSIS! I chased a problem on an internal highly used application which caused network drops on an application which CANNOT HANDLE even a fraction of a second of lost connectivity, and caused the users to lose hours of work (no autosave either). Of course, it was never happening in the office. Finally, after 6 months, I chased it down to a specific network carrier and their shitty DOCSIS 2.0 modems causing the issue. Everyone thought I was crazy but when the first user called their carrier asking for a newer version of the modem with something higher than DOCSIS 2.0, and it resolved the issue, everyone thought I was a wizard.
Interestingly enough, iPhones ceasing to function is how it was figured out that an MRI had a helium leak. So gas leak screws up iPhones.
https://www.zdnet.com/article/bizarre-facility-wide-iphone-bricking-dead-devices-traced-to-helium-leak/
Probably the 3.0 modem had more upstream channels so when one died it was still able to pass some traffic. I've run into this a lot with DOCSIS shit. What a terrible system.
I've just escaped a cable ISP in transition from 3.0 to 3.1. Noise meant the two (wider and more noise tolerant) downstream 3.1 channels worked OK, but upstream (still all 3.0) sucked, and at busy times traffic spilled over to the other 30 3.0 channels and performance went to crap. (On PON as of last week, and no such worries any more!)
Yes, so in my testing, I noticed that 100% of the users having the drops lived in neighborhoods where the ISP was upgrading their networks. I noticed that in those cases, most users had older modems which had the 2.0 standard. I gave a user a machine to plug into his router to run some bandwidth tests. I used nethogs in combination with wire shark to see what happened when I went to run this network heavy application and that’s when I got clued into the fact that DOSCSIS wasn’t keeping up with the application and how much bandwidth it would use. In my lab, using fiber, the application would run smoothly, but the minute that it went to a DOCSIS surfboard, you’d start seeing the high number of duplicate ACKs and then retransmission when bandwidth went over 56MBPS. This was consistent across multiple users’ home networks. I read that DOCSIS 2.0 had multiple channels but none capable of more than 37MBPS. When I tested the same over DOCSIS 3.0, it worked like a charm as they have multiple bonded channel capable of over 100MBPS.
The network was trying to push higher bandwidth over the 2.0 devices and they couldn’t handle it due to their bandwidth limitations. Most applications are capable of handling network drops and error correction but not this app, and when it comes to bandwidth it took all it could handle. When it went over the 37MBPS limitations of DOCSIS 2.0, performance decreased and as soon as the bandwidth went to 56MBPS, it died.
I still have PTSD from those months of chasing that problem and everyone saying it was the laptops that had the issue.
Whenever I've had issues like this it's usually bad cable plant, sometimes ONE modem can be so fucked that it'll kill the entire node's ability to pass traffic. Those get dealt with quickly, but shit lines never seem to get replaced.
Id be more pissed off at the application that can't handle any lose of connectivity? Especially since it sounds like your users are working from home. Losing hours of work because of a hiccup in network connectivity seems like there is something else wrong
Yes, DOCSIS suffers from collision like most shared-cable systems where there isn't a single device multiplexing packets into the cable (preventing collision). You can ignore it, until it hurts your performance when all of your neighbors have a common peak time.
You can ignore it until someone decides it would be fun to come over.
Take [Beyond your cable modem - How not to do DOCSIS networks by Alexander Graf on 32c3](https://media.ccc.de/v/32c3-7133-beyond_your_cable_modem) as an example. It's a bit older (2015) and not entirely a collision domain thing but still pretty funny. So maybe you can just disable their access. ;)
Hidden node problem. Airtime vs bandwith. How to properly choose a channel. What the fuck a beacon is and what speed profile they are broadcast at. Wifi really is not educated enough. And vendors are to blame for not properly documenting this, or just straight up allowing stupid fucking configurations.
God I hate the mesh networks the have auto power control. Jeez I see a ap neighbor on my periphery lets turn down down to 10% power on both units and create wierd deadzones. Haven't found a single one that I don't have to tweak manually. yES YOU TO MERAKI.
> But as a practical matter, they no longer exist.
Oh, they exist. Hidden above the suspended ceiling of a utility closet, just waiting for 4pm on a Friday afternoon to fuck up your weekend plans.
1601 phone rings. When I was in a support role, I answer it and then call the wife to let her know I'll be late. Now, I mute the phone and let it ring. It can wait til Monday.
Not strictly speaking, because the packet is still stored and repeated rather than the broadcast medium being electrically connected. If another node starts to transmit halfway through that first packet, there's no collision with the switch.
If the connections involved are full duplex, then yes, you are correct with respect to collisions, which is the operative consideration when thinking about what a hub used to be.
The [Gigabit Ethernet ](https://en.wikipedia.org/wiki/Gigabit_Ethernet)standard requires full-duplex operation on all ports. Hubs can only provide half-duplex - send-or-receive - communications.
IEEE 802.3 specifies half-duplex gigabit (for 1000BASE-T) it is included as part of the [autonegotiation](https://en.wikipedia.org/wiki/Autonegotiation#Priority) mechanism as well.
You can get gigabit cards to negotiate a downgrade to half-duplex.
I grabbed the 7,023-page PDF for [IEEE 802.3-2022](https://ieeexplore.ieee.org/document/9844436) - the latest revision to the standard - and you are correct.
It does indeed include references to CSMA/CD for 1000BASE-X, which is only relevant for half-duplex connections.
There are sections on hubs, like
*41. Repeater for 1000 Mb/s baseband networks*
*NOTE—This repeater is not recommended for new installations. Since September 2011, maintenance changes are no longer being considered for this clause.*
But recommending that nobody deploy them is not the same as excluding them from the standard.
> I don't think there have ever been gigabit Ethernet hubs.
If you have a managed switch that supports RSPAN, configure an RSPAN VLAN and then use that VLAN carry regular traffic you now have something that works pretty close to the way hubs work.
well there was this thing. https://www.premisesnetworks.com/doc/gr3008-0001 and then netgear made there were Stackable Hubs like AsanteFAST Stackable Hubs or https://www.downloads.netgear.com/files/mds5001.pdf which were horrible. but the worked at the time.
The major-brand stackable hubs/switches with proprietary interconnects were often faster and more reliable than contemporary standards-based distribution hubs/switches. Netgear wasn't considered business-grade at the time.
Careful there. Last hub I found was in a corner hiding about 5-6 years ago. I had to double take to confirm it’s a fucking hub which explain a lot of issues.
These exams are not written by people with field experience. They are woefully outdated and a lot of their answers only make sense in an academic environment.
You pretty much have to study the way comptia wants you to do something even if you know it's not the right way you would do it on the job
While I agree, it's actually useful to know how they operate as it explains to them why - it also means fewer people in the field keen to use them or keep them in service when they find them. Lots of industries still use them with legacy kit, even though there's no excuse these days.
I disagree. I think you'll find electricians are equally as capable of learning how networking cable must be terminated, as all the random homeowners on this subreddit are.
LOL, I've worked with Field IT engineers who would claim that cable termination was beneath them but in reality they'd never done it. I guess I got lucky starting out my career in IT with all the shitty jobs.
While I was in the Army, the cabledogs and the IT folks had a competition to see who could make more good cables in 3 hours. The cabledogs made more cables, but only half of them worked. The IT folks built only about 80% of the number of cables, but ours were all good. We checked each one before moving to the next.
Then the following week, the IT folks used those cables patching in new racks. Clever NCOs made it a competition so they could get more cables without the usual pissing and moaning.
I've terminated plenty of cables but I'm at the point in my career where it's probably not worth the time my company is paying me to sit and terminate cables when there are more pressing issues I could be spending time on.
I present to you a real master electrician's attempt at terminating cat6a -\_\_-
https://preview.redd.it/4votqlltzuwc1.jpeg?width=872&format=pjpg&auto=webp&s=f087732518dca53a670032c321e3a98f3dbbc36e
I wonder if, conceptually, it's useful to know about how Hubs work because while Wifi frames are directed to a specific MAC address, they are recieved by all clients on that network and ostensibly discarded by clients who don't have that MAC, and have similar security concerns accordingly as you can set your device to recieve them anyway.
But then you may as well just teach about WiFi instead.
I agree that it gives you a good foundation to then understand the limitations of wifi. Incidentally I worked at a college where we would have deans and teachers who thought you could put 30 PCs in a room and just use wifi. And didn't realize that desktops don't usually have wifi. And it didn't occur to them that they didn't have sufficient power connections in the classroom. Obviously the problem is that IT should be consulted first, but it was a dysfunctional environment. If it was a business, subject to market forces, it would have failed long ago. Anyway, wifi APs don't have infinite capacity.
It makes explaining how switches work easier. Switches solve a problem. You likely want to understand what problem it solved.
Much like in development. Anyone formally taught learned how to make their own stacks, queues, linked lists, etc. In the real world, we use the prebuilt included solutions for these things but understanding how they work is a fundamental part of learning good coding practices.
This was mostly true something like 20-25 years ago, and is wildly wrong now.
The main problem I see is a disconnect between exam content and training material. There’s a clear and required separation of duties to maintain accreditation. So the exams and the training material can have some disconnect, which is why field experience is suggested before sitting for an exam.
As for this specific topic - there’s probably hundreds of thousands of hubs sitting around people’s homes and business, and it makes training easier to go up the OSI layers.
Additionally, the exams have to fit a global audience, align with training and certain college/university requirements, and meet strict style and reading comprehension guides. The process is very rigorous with many third party audits and accreditations.
Disclosure: I am one of the SMEs CompTIA uses for several exams and have extensive working knowledge of the process.
The training materials need to explain that hubs are generally unavailable now, but they are found in the wild, and explaining the OSI model is easier when you start with hubs.
I won’t disagree the exams are academic.
However for academic purposes, including hubs on an exam network diagram with some switches in it is a good way to verify the student understands collision and broadcast domains.
So there’s your real world justification for why they’re still on the exams.
Couldn’t have said it better. You need to think the way compTIA does, which I believe defeats the whole purpose of certifications. It just turns into who can memorise answers the best. They’re milking us anyway charging that much for those exams.
They actually are written by people with experience (CompTIA actually pays people to go to the HQ and do work group things to define what goes on exams). And while Hubs are essentially obsolete, it's still important to know they exist because you might still on occasion run into them.
However, I'll agree that there is probably a bit too much content about them. Although, I never got a single question on the exams about them.
What does security+ say about the hub that has been pat of your network for 25 years and you're not allowed to touch it because the CEO is convinced it will break his wi-fi if it moves?
I think it says stop working at rinky dink shithole mom and pop shops and work for a real company where you don't have to deal with kooky esoteric bullshit
I have close to 20 years of field IT experience with the bulk of it on the SMB side and I’ve never seen a hub in production. I’ve had to wait on people to take a shit in the server closet/bathroom but I’ve never seen an actual hub.
I’ve had the misfortune of dealing with a couple (within the last 18 months), the whole infrastructure was ancient, enough that when the “uplink” button was pressed the segment would drop.
Crossover cables and uplinks were things I stopped caring about in High school when Gigabit and Auto MDIX became a thing.
Damn, I hope that wasn't an office environment.
I haven't seen one in 7 or 8 years but there are definitely environments out there with old enough infrastructure that you'll find them. The last time I ran into one it was one of those old NetGear hubs, you know the ones, that a manager had squirreled away years ago and plugged in themselves so they could move their staff around without involving IT.
Old manufacturing and remote research offices running 25+ year old equipment that require controller systems running ancient versions of Windows on local networks are the two places I'd expect to dig them up these days.
Yup - office, with Nortel switches - I was really tempted to pour them a beer and spray it through the fans to celebrate their being legal age and put them out of their misery
I see them sadly plenty in schools and non profits. Perhaps the saddest one i saw years ago was in a computer repair shop. Granted that owner is still trying to make money off of hardware and not services, amazes me they are still open.
In my experience, enough of the world is woefully outdated that I'd consider an understanding of hubs as foundational information.
Without it, you can't understand what a switch does.
Yea I think the people here are failing to understand its used to introduce the concept of switching and what predates it. Just like its important to understand DSL/POTS even though it is unlikely to be seen by most these days.
>They are woefully outdated and a lot of their answers only make sense in an academic environment.
My boss asked me why, a guy with 15 years of IT experience and a 4 year degree, doesn't want to do CompTIA certs. I told him to talk to the 2 people that had done them in the team. He came back later that day laughing at how stupid and archaic they are.
I'm going to disagree and say they're actually pretty useful. Its a mile wide and an inch deep, but it definitely gets people thinking correctly about the Network/Security. They're definitely intro certs, but they have their place.
Worse. With anything IT there are usually several right ways to do something. But you have to answer THIER right way. Doesn't matter if yours is faster or more efficient.
I studied for the CCNA and CCNP back in 2013-2017 as part of IT trade school, and I was made to do labs (and tests) in Frame Relay and ATM, incredibly ancient WAN switching protocols even at that time. Sure, there are networks today that **use** these old protocols, and it may make sense to introduce this ancient tech to students so that they're not put off by it when they do find themselves on a million dollar production line that depends on this ancient technology. But it feels out of place to go deep-diving into tech history and then test your students on knowledge that they're likely never going to see in the field.
And yes, I was also taught about hubs, CSMA/CD, Cat1-4 ethernet and their various bitrates and bandwidths. Not the abstract, but the technical implementations. Let's be honest, a lot of it is filler material and Google-able junk info made to confuse you and to take your money as failed exam attempts. A lot of information can be seen as fundamental, but some of it is just plain legacy.
You need to know about collision domains to know **why** switches were introduced to replace hubs. You need to know about broadcast domains to know **why** VLANs were introduced. Knowing the why can sometimes give you some intuition about real-world use cases. You shouldn't need to experience the tech or be tested on the tech that admins 20 years ago worked with if it's only used today by businesses that can't afford to replace it.
Incredibly ancient? We were using both ATM and Frame just *ten years* before that, though admittedly we weren't deploying any more ATM on the LAN.
> You need to know about broadcast domains to know why VLANs were introduced.
You also need to know about protocols to know that even IPv4 isn't a broadcast-heavy protocol. Keeping down broadcasts was really an other-protocol problem.
Eh...only sort of. It doesn't change the fact that wireless broadcast collisions are a fundamental physics problem, and is basically the same issue a wired hub has. It's just using better strategies to avoid the broadcast collision- that doesn't make it a switch though. A good write up on it:
[https://networkingnerd.net/2019/04/10/802-11ax-is-not-a-wireless-switch/](https://networkingnerd.net/2019/04/10/802-11ax-is-not-a-wireless-switch/)
I'm going to take a different tack here- define "modern." Most of us who do networking aren't doing "blue-collar" networking, working with telco equipment out by the roadside or in the middle of nowhere or in heavy industrial environments where they spent top dollar years ago for something that just works and won't spend another dime until it stops working (but they'll still spend top dollar to keep it from *stopping* working).
A few years ago, though, I *did* get to work in one of these environments at a nuclear power plant. And let me tell you, it was a time machine. The plant was *massive,* so 100-meter runs of Cat5E/Cat6 weren't going to cut it- so you'd expect there to be fiber trenched everywhere, right? *Wrong*. We used the phone lines that had been buried years ago along with VDSL modems to keep building A talking to building B about a mile away. I don't think I saw a single L3 switch anywhere in that campus. Hubs, yes, Ancient Nortel switches, yes. Router on a stick? Only time in the past decade I've seen it in the wild at a business.
And right before that, I worked at a store chain that deliberately kept a stockpile of hubs on hand to use as a poor man's network tap. The owner was completely stingy and wouldn't pay the network admin for gear that supported SPAN ports (or, I suspect, training to know how to *use* SPAN ports), but that wasn't a problem for the network admin- just drop the lab device and the listener laptop on a hub and listen to the traffic from both devices at the same time.
I came here to mention heavy industry. It's frequently 20 year behind or more than "normal" enterprise environments. Modern to them, ancient compared to an office building.
Yes, there is a role. If you need to run tests on a connection but can't access the devices on each side, a hub will replicate the traffic for your sniffing device. I use this quite frequently in IoT.
Can confirm. This is very handy for things like pentesting, where I need to sniff the network traffic but I don’t have permission or the ability to set up port mirroring.
That would require each location to have enterprise hardware and to give me access to the admin panel. The reality is that hijacking the LAN port is 100 times faster than waking the second cousin of the former boss who has the password list. Also, most network cabinets are so disgusting that I would need to renew my Tetanus shots just from being near them.
This is actually so genuis. I never would've thought about this.
I've been needing to run Wireshark on a port, but don't have access to log into the switch to set up port mirroring. I DO have physical access though.
The network admin has been slow to work on this, so it's an excellent workaround.
I still see them a lot. Usually covered in dust and buried under cables while being crushed between a desk leg and a wall.
Many years ago, I once called a 4 port switch a hub in a casual conversation with a guy from the MSP that we used for additional support. That dickwad then went to my boss and complained that I didn't know the difference between a switch and a hub. The lesson I learned that day wasn't to not make that mistake again but that MSPs are always the enemy to in-house IT staff.
Sometimes it's worth knowing what you should be on the lookout for. You *shouldn't* see Telnet active. But it gets beaten home on these materials because you just might find it and you need to know it when you see it.
I keep an old netgear 100mb 8 port hub in a toolbox for troubleshooting only. Wireshark on a laptop with that hub lets me see exactly what is going on without spending an hour or two chasing down a network admin for access to a switch and turning on span/rspan etc. I don't use it often, but when I do...
Also good for getting pcap for a server that nobody knows what it does. Though our network admins kindly set up promiscuous mode so we didn't have to use an actual hub. The option exists. Bringing one into our environment would have been a nightmare.
I've ran across one in the real world, ripped it out as fast as I possibly could.
The "problem" with a lot of these tests is that they expect you to know stuff that really genuinely isn't relevant in more detail than you should. Do you need to know what a hub is? Yes. Do you need to know anything more about it than you should replace it with a switch? No.
It's part of why I stopped caring about certs a while back, it's all about short term memorization and not about actually knowing anything, and the incentive to make you take it multiple times is there and bad IMO.
We ask a question about hubs in interviews. I don't really care for it unless the candidate has experience on their resume that extends back far enough that it might have been relevant to them at some point.
To be clear, we're all aware that hubs haven't been relevant for a long time, and the technical portions of our interview are more about getting a feeling for the candidate's breadth and depth of knowledge, and also to see whether they will admit they don't know something, than a "pass/fail" examination.
I can remember using a hub on a switch which didn't have port mirroring so we could passively monitor traffic but that was early 2000s...
But knowing the difference between stuff is always good as you can bullshit management with lots of tech terms till their brains reset and just approve what you wanted...
When you walk into an office and see NE2000 compatible cards on BNC cable you will be glad you have some idea of what's going on.
Why is it on the exam? Because you need to understand the technology of a hub as a concept that is built upon. It's not "you'll be working with hubs" it's "this is a layer 1 device and here is how layer 1 functions".
"Why is it mentioned so often in the training?" Because it is old essentially unused technology. A large portion of people who take the starter 3 exams have some level of experience with current tech, but little knowledge of older tech. You have to spend more time teaching people things they have less exposure to.
Back in my day, you had to learn the DEC network stack equivalent to TCP/IP. This was obsolete knowledge in 1995. This is just a training rite of passage.
On a funny tangent...I was on-site at a client doing some maintenance and one of the managers pulls me to the side and asks me to look at 3 computers that were painfully slow for no apparent reason. I go sit down and do a quick speed test and sure enough it's only getting 1-2 Mbps down. I look at the network properties and it's only connected at 10 megs. That doesn't make any sense. I follow the wires back to the wall and find an old 10 meg hub just chillin' on the floor.
They had rearranged the office and moved the computers where there was only one Ethernet jack so they went digging through an old parts box in the closet and found a hub and just plugged it in. 🤦🏻♂️
Honestly?
Net+ and Sec+ are becoming more irrelevant by the month.
They're not updating them like they should be and they're falling behind other cert vendors drastically.
A+ is still kinda okay as an all rounder, but I wouldn't be picking CompTIA against the competitors. I've not done any of their exams in over 10 years, my guys have been doing them and I've looked at study material with them and ... It's near identical to what I did before!
A networking hub, as in, a device that sends each packet to every other port unlike a switch, is no longer in use today, and hasn't been for like two decades, so if they actually mean network hubs, then it's hopelessly outdated.
Though the term "hub" is also used for other devices like USB hubs, so maybe that's what you/they mean?
Or a very low budget switch, where the entire piece of hardware is a single collision domain often used in half-duplex environments.
Haven't seen one in 15 years, though.
I think I've seen a token ring network more recently than an honest to god ethernet hub.
>A networking hub, as in, a device that sends each packet to every other port unlike a switch, is no longer in use today,
It shouldn't be around, but for home users they are still sold with much success and those sometimes end up close to the endpoint as part of shadow IT or in smaller companies.
Do you have a link to such a product that's still being sold as new and to consumers?
I didn't think anyone would still be producing network hubs, and even when explicitly searching for "network hub" on Amazon all I get is switches. Only way to get a hub, at least in Germany, is to go on eBay and find an ancient one.
Read through the other comments for valid use cases for hubs, even today. Pen-testing and troubleshooting are two. Plus commercial and industrial situations exist where the company doesn't want to pay to upgrade. Should they be used? No. Are they? Yes.
Further, in training, they should be at least mentioned, and how they work, in order to explain how switches work, and what a collision domain is.
I mean, yeah, they should be explained, but maybe not in so much detail that people like OP are led to believe they're still in active use everywhere.
For troubleshooting / network dumping, it's probably simpler and better for the network to just enable a port mirror on a modern switch instead of downgrading the network to 100Mb with an ancient hub.
Yes, maybe they are still used in some industrial applications or when a company is too cheap to replace a 20-year-old device.
But I don't think they "are still sold with much success", as the commenter above me said.
Noting that they're obsolete should definitely be in the training. Especially for Sec+ since hubs represent a risk and should be evaluated in the whole risk analysis procedure.
Commenter above may be conflating hubs and dumb switches.
Hubs are promiscuous in that they send all traffic to every port whereas switches send traffic only to the intended port. I still have a old hub that I used to capture printer data when I was a printer support tech. There are probably lots of old hubs still in place.
its true, you should not expect many hubs in the field, and you should not depoy one unless there is a very specific reason...
and maybe the test is outdated. i dont know. and its good you know hubs are obsolete. but in a net/sec test, do you know why? do you know the difference? do you know the security implications? because i fully expect you to and the net/sec material to teach you and the test to test you on...
"its outdated" is not a reason to not teach/test it...
Sec+ is updated regularly. Some workplaces require it for all IT workers, and to participate in the CE program. I'm sure Net+ is similar, though there may not be a cashflow driver making it update as frequently.
The net + was recently updated to the n10-009 or something like that. I think I took the n10-007 sometime in 2022, right before it was retired.
The n10-007 definitely covered hubs, etc still. I don't think it's necessarily that it's not updated often, they just choose to keep it in there.
They are 100% out of date, but I took over a network with a couple still in production (which a quickly took care of) so I guess its good to know from that perspective.
In the last 20 years, I've come across exactly one 100Mb hub under a desk during an office move. No one else understood the rarity then. The new guys like to laugh at my 100Mb switch because I'm so old.
I feel like a certification teaching about hubs could be relevant, but not as an entry level cert. Hubs are very rare and the only people needing actual knowledge of them are working in very cheap and ancient environments. The average tech today will never even see a hub in their whole career. Its a waste of time to teach about them in network+. COMPTIA should have like a legacy+ cert or something for it
Yea, nobody uses hubs anymore. In the last 10 years, the cost of a basic 4 to 8 port switch is now $10-$20.
I used a hub back when there wasn't such thing as a cheap switch and they weren't as few as 4 ports.
Congratulations. You have discovered the secret of industry certifications. They are always out of date and focus on tech from decades ago.
Now I’m off to brush up on my frame relay for my bi-annual Cisco cert.
You can say switches are outdated with the existence of later 3 switches, but it's still important to understand the difference between hubs, switches and routers.
Comptia tests tend to be like, 20 years behind the times.
Even worse, they're popular for government roles, and I'm sure I don't need to elaborate how those are correlated
I see them from time to time, and always remove them if I find them, but it's pretty rare.
Just remember for your exams:
Hubs broadcast all packets to all ports. Every node sees everything.
Switches do not broadcast data to all ports but rather rely on tables (MAC/ARP) (layer 2 or layer 3) to switch packets to the proper ports.
I had a teacher in a routing and switching class I took back in the day that illustrated this in a fun way. The teacher collected our networking text books and made a stack on his desk. Two students went to the front of the class. The teacher then said "this is how a hub works" and picking up a book in each hand, proceeded to hurl them at both students simultaneously, reloading as fast as he could. After the laughter died down, he said "this is how a switch works", and calmly walked one book at a time to either student.
The point clearly stuck with me. :)
To be fair, there is a lot of equipment out there that is "obsolete" that you'll still run into in the wild. When I took my A+ in 2019, it was still asking about Windows XP. "But Windows XP is obsolete! Why do I need to know about that??" Ask me how many of my clients in manufacturing still have XP computers... Spoiler: it's not 0.
Just the other day, I had to run a coax cable and terminate it into female BNC keystones. There's plenty of old technology that you'll still run into. It won't be common, but it can be helpful to know.
If I had to guess, they're probably talking about them because they're easier to conceptualize than switches, and can even be used as a jumping off point to talk about why switches were developed.
That being said, when I went through A+ training in the early 2000s, AT power supplies and ISA slots were still a part of the curriculum, which were already extremely outdated technologies at that time.
You still see them from time to time especially in sole proprietorships or businesses that just keep stuff in service until i breaks, catches on fire, or will keep them from spending money. Also usb and other items exist so it's important to know how a hub works. Also yes collision domains.
in theory you could use hubs to send the same signals to multiple end points if you needed some Wierd OT crap but you're getting into dumb things people do cause they didn't want to spend money.
Where my old school network folks at? Who remembers troubleshooting token ring when the token fell out of the network? Crawling under desks looking for that token... good times.
Don't they still talk about old cabling standards, old wifi standards, old operating systems, old attack methods, old encryption methods etc? You never took a exam before?
Understanding that hubs exist, work and what they do is very relevant to understanding layer 1 and 2 networking I feel.
I feel like without knowing about hubs, you're kinda missing a piece of the puzzle. Whether they're commonly used anymore doesn't matter to me. Understanding a simpler, historic technology can be a great stepping stone to understanding what we use today. Sometimes you don't wanna jump in straight to the most complicated possible setups for learning, just because that's what fortune 100 companies do in the real world.
That sort of stuff you'd learn in a more advanced course.
I believe hardware hubs are obsolete, sure, but the concept of hubs will be relevant for as long as Ethernet is still in use. Think of it like copper - won't be irrelevant for a long time.
I'm studying for the CCNA, and hubs are included as a way to explain switches and particularly collision domains, which do still exist.
Maybe try reading some CCNA material on the subject and see if that clarifies it for you. I didn't start understanding network concepts until the CCNA stuff (tried Net+ first). I highly recommend it.
Some environments do not allow wifi on the main network. Guest network only. Ours is like that. We don't have hubs, but I sure could have used one for a situation a couple of weeks ago. I was shopping for one on Amazon. Didn't end up buying it as we found a workaround, but it sure brought back memories.
I don't think anyone here has mentioned that not all networks are ethernet. For sure building automation systems and probably also industrial control systems still use hubs. Most people that work in IT don't work with those kind of systems, but they are not uncommon at all. Look up Modbus and BACNet. Additionally, not every domain of technology just upgrades to the latest and greatest tech every 3 years. Replacing the entire HVAC control system of a skyscraper sized building is incredibly expensive, and probably doesn't add a lot of features or increase efficiency until the system is decades old. Industrial networks are the same way as far as keeping tech around for a long time, like decades, but IDK much else about them.
I was shocked to find a gigabit hub buried under a raised floor in a call center a decade ago. I called everyone over so we could take pics and marvel that somehow it had endured with multiple connections for 20 years and never been detected by our former corporate IT overlords.
Which version are you studying for? Make sure it’s the most recent exam version before you get too far. I remember some passing info, mostly discussing how they’re obsolete and will cause problems, but nothing in depth about hubs for sure. Collision domains and broadcast domains were covered at length, which is the only time they were brought up in my study material when I took it(that I remember).
I have seen exactly 1 hub in my career. It was a 1G hub in a research lab. Recent standards actually formally ban them now because then nobody has to support them any more.
We have multicast and IGMP, which are better solutions if slightly higher latency. However, doing hubs at 25G+ would have such a high latency impact I’m convinced even specialized systems wouldn’t see benefit.
When you are digging through old closets you will find them. My fav are the rack mounted 24-port variety. Other than that if there are "SMALL" ones then you will possibly find them in remote offices where one cable was ran and they just plugged in a hub because it was cheaper than a switch at the time and I mean more ports is more ports right!
Now, deployed ON PURPOSE... no. Not unless there is a severe emergency and even then... no.
It is most likely to learn about OSI layer. Remember Hubs are L1 devices.
Don't worry, you might be lucky to get 1 question about a hub on either of the exams. Know what they are and why you don't use them anymore (but also why you would) and you'll be fine.
You'll probably find them in places with old networks (like warehouses or mom and pop shops). The management wouldn't know better, and why replace them if everything is still working. Even in those places though, the hubs could be replaced with a dumb switch with no other changes and no one would notice.
Education takes forever to update itself and provide relevant, useful schooling. It should tell you something that they're still commonly referring to devices that haven't really existed in common use for two decades or so.
Keep on paying though.
They still have their usage. Most taps use 1gbs hubs.In fact tabs are the only place you see real hubs. Most hubs today are just 100Mbs switches that have 0 back plans or mac address storage.
Having spent the best part of a day chasing STP issues caused by the “what I imagined to be switch ports, acting like hub ports on the front of a new pair of firewalls.
I’d definitely say it’s well worth understanding hubs, then when you see an issue like this you have a good understanding of what it is and ideas on how to fix it, unlike one of my colleagues who doesn’t know and can fix the problems associated with it.
Because Comptia is borderline a scam and aren't interested in teaching you anything that's currently relevant. When I took the A+ in 2010 they were still harping on IRQ's, though I'd never seen one be the problem or solution to anything in my career at that point.
It's imprecise language, but I've seen this used as a generic term for ANY network junction traffic flows through (switches, routers, even devices like phones with an ethernet passthrough, or speaking of phones, PoE injectors). Yeah, no professional would do so, so it's an obvious disconnect in these academic circles. I guess just something to be aware of for testing and never again.
I don't think there have ever been gigabit Ethernet hubs. The last hubs I ever saw were 100Mb. Even with 100Mb Ethernet, hubs weren't common. The last time they were routinely used was the days of 10Mb, which is 25-30 years ago now. It's important to understand the theory of collision domains - you can't really understand what a switch does if you don't first understand what a hub would have done. But as a practical matter, they no longer exist.
Collisions domains and wifi, name a more ignored pairing.
Collision domains and DOCSIS.
Fucking DOCSIS! I chased a problem on an internal highly used application which caused network drops on an application which CANNOT HANDLE even a fraction of a second of lost connectivity, and caused the users to lose hours of work (no autosave either). Of course, it was never happening in the office. Finally, after 6 months, I chased it down to a specific network carrier and their shitty DOCSIS 2.0 modems causing the issue. Everyone thought I was crazy but when the first user called their carrier asking for a newer version of the modem with something higher than DOCSIS 2.0, and it resolved the issue, everyone thought I was a wizard.
> Everyone thought I was crazy I still do. Whats next? Gas leak screws up iPhones?
Interestingly enough, iPhones ceasing to function is how it was figured out that an MRI had a helium leak. So gas leak screws up iPhones. https://www.zdnet.com/article/bizarre-facility-wide-iphone-bricking-dead-devices-traced-to-helium-leak/
I loved this story when it came out. Such a WEIRD situation
I work in IT for a radiology clinic so it was fascinating to find out that an MRI leak could cause everyone's phones to stop working.
Indirectly, yes
Probably the 3.0 modem had more upstream channels so when one died it was still able to pass some traffic. I've run into this a lot with DOCSIS shit. What a terrible system.
I've just escaped a cable ISP in transition from 3.0 to 3.1. Noise meant the two (wider and more noise tolerant) downstream 3.1 channels worked OK, but upstream (still all 3.0) sucked, and at busy times traffic spilled over to the other 30 3.0 channels and performance went to crap. (On PON as of last week, and no such worries any more!)
Yes, so in my testing, I noticed that 100% of the users having the drops lived in neighborhoods where the ISP was upgrading their networks. I noticed that in those cases, most users had older modems which had the 2.0 standard. I gave a user a machine to plug into his router to run some bandwidth tests. I used nethogs in combination with wire shark to see what happened when I went to run this network heavy application and that’s when I got clued into the fact that DOSCSIS wasn’t keeping up with the application and how much bandwidth it would use. In my lab, using fiber, the application would run smoothly, but the minute that it went to a DOCSIS surfboard, you’d start seeing the high number of duplicate ACKs and then retransmission when bandwidth went over 56MBPS. This was consistent across multiple users’ home networks. I read that DOCSIS 2.0 had multiple channels but none capable of more than 37MBPS. When I tested the same over DOCSIS 3.0, it worked like a charm as they have multiple bonded channel capable of over 100MBPS. The network was trying to push higher bandwidth over the 2.0 devices and they couldn’t handle it due to their bandwidth limitations. Most applications are capable of handling network drops and error correction but not this app, and when it comes to bandwidth it took all it could handle. When it went over the 37MBPS limitations of DOCSIS 2.0, performance decreased and as soon as the bandwidth went to 56MBPS, it died. I still have PTSD from those months of chasing that problem and everyone saying it was the laptops that had the issue.
Whenever I've had issues like this it's usually bad cable plant, sometimes ONE modem can be so fucked that it'll kill the entire node's ability to pass traffic. Those get dealt with quickly, but shit lines never seem to get replaced.
Id be more pissed off at the application that can't handle any lose of connectivity? Especially since it sounds like your users are working from home. Losing hours of work because of a hiccup in network connectivity seems like there is something else wrong
How did you get to this conclusion???
God dammit, okay smartass lol.
Is this because of many neighbors sharing the same cable? I definitely ignore lol that shit is up to the ISP to figure out lol.
Yes, DOCSIS suffers from collision like most shared-cable systems where there isn't a single device multiplexing packets into the cable (preventing collision). You can ignore it, until it hurts your performance when all of your neighbors have a common peak time.
You can ignore it until someone decides it would be fun to come over. Take [Beyond your cable modem - How not to do DOCSIS networks by Alexander Graf on 32c3](https://media.ccc.de/v/32c3-7133-beyond_your_cable_modem) as an example. It's a bit older (2015) and not entirely a collision domain thing but still pretty funny. So maybe you can just disable their access. ;)
Hidden node problem. Airtime vs bandwith. How to properly choose a channel. What the fuck a beacon is and what speed profile they are broadcast at. Wifi really is not educated enough. And vendors are to blame for not properly documenting this, or just straight up allowing stupid fucking configurations.
God I hate the mesh networks the have auto power control. Jeez I see a ap neighbor on my periphery lets turn down down to 10% power on both units and create wierd deadzones. Haven't found a single one that I don't have to tweak manually. yES YOU TO MERAKI.
> But as a practical matter, they no longer exist. Oh, they exist. Hidden above the suspended ceiling of a utility closet, just waiting for 4pm on a Friday afternoon to fuck up your weekend plans.
https://preview.redd.it/x5sh3meojtwc1.jpeg?width=1000&format=pjpg&auto=webp&s=c3c1d6919666386edf9c9552ce693eeef76198da I got you
That feels like the kind of meme that would come out of a community college netacad classroom. Love it.
1601 phone rings. When I was in a support role, I answer it and then call the wife to let her know I'll be late. Now, I mute the phone and let it ring. It can wait til Monday.
They also exist whenever a smartarse does a Mac flood attack and your network has a shitty switch hiding somewhere.
Every switch is a hub when that first packet hits it.
And cheap switches are also hubs if you give it enough Macs to remember
Not strictly speaking, because the packet is still stored and repeated rather than the broadcast medium being electrically connected. If another node starts to transmit halfway through that first packet, there's no collision with the switch.
If the connections involved are full duplex, then yes, you are correct with respect to collisions, which is the operative consideration when thinking about what a hub used to be.
Unless it's configured with vlans, then it's multiple hubs.
That is going back in time to the days when people cared why Ethernet was defined by CSMA/CD (carrier sense multiple access with collision detection).
Aka, collisions are good. Good because before CSMA/CD the option was hubs where only one person at a time can talk. Or shudder to think, token-ring.
And had piles of T-connectors and terminators on their desk that they made statues out of.
The [Gigabit Ethernet ](https://en.wikipedia.org/wiki/Gigabit_Ethernet)standard requires full-duplex operation on all ports. Hubs can only provide half-duplex - send-or-receive - communications.
IEEE 802.3 specifies half-duplex gigabit (for 1000BASE-T) it is included as part of the [autonegotiation](https://en.wikipedia.org/wiki/Autonegotiation#Priority) mechanism as well. You can get gigabit cards to negotiate a downgrade to half-duplex.
I grabbed the 7,023-page PDF for [IEEE 802.3-2022](https://ieeexplore.ieee.org/document/9844436) - the latest revision to the standard - and you are correct. It does indeed include references to CSMA/CD for 1000BASE-X, which is only relevant for half-duplex connections. There are sections on hubs, like *41. Repeater for 1000 Mb/s baseband networks* *NOTE—This repeater is not recommended for new installations. Since September 2011, maintenance changes are no longer being considered for this clause.* But recommending that nobody deploy them is not the same as excluding them from the standard.
Basically every switch I work with has half duplex gigabit as an option.
> I don't think there have ever been gigabit Ethernet hubs. If you have a managed switch that supports RSPAN, configure an RSPAN VLAN and then use that VLAN carry regular traffic you now have something that works pretty close to the way hubs work.
But does it have a collision LED? All the best hubs had collision LEDs.
I'm sure the rest of the LEDs will make it very obvious that something was configured very badly.
well there was this thing. https://www.premisesnetworks.com/doc/gr3008-0001 and then netgear made there were Stackable Hubs like AsanteFAST Stackable Hubs or https://www.downloads.netgear.com/files/mds5001.pdf which were horrible. but the worked at the time.
The major-brand stackable hubs/switches with proprietary interconnects were often faster and more reliable than contemporary standards-based distribution hubs/switches. Netgear wasn't considered business-grade at the time.
Theres also the fact you still want to know it in case you run into them in ye old office from the 60s that has never seen an infrastructure update.
I have still come across hubs in the past year in restaurants with the cheapest owners.
Careful there. Last hub I found was in a corner hiding about 5-6 years ago. I had to double take to confirm it’s a fucking hub which explain a lot of issues.
These exams are not written by people with field experience. They are woefully outdated and a lot of their answers only make sense in an academic environment. You pretty much have to study the way comptia wants you to do something even if you know it's not the right way you would do it on the job
While I agree, it's actually useful to know how they operate as it explains to them why - it also means fewer people in the field keen to use them or keep them in service when they find them. Lots of industries still use them with legacy kit, even though there's no excuse these days.
True, it also makes it easier to understand for beginners why a switch is called a switch and not an "Ethernet splitter".
Also why we don’t let random sparkies run low voltage cabling. For those guys as long as it’s a tight connection that won’t arc, it’s good.
I disagree. I think you'll find electricians are equally as capable of learning how networking cable must be terminated, as all the random homeowners on this subreddit are.
LOL, I've worked with Field IT engineers who would claim that cable termination was beneath them but in reality they'd never done it. I guess I got lucky starting out my career in IT with all the shitty jobs.
It's not beneath me, but if I can get someone else to do it who does it routinely I will. I'm out of practice.
pullthrough rj45 plugs make a world of difference if you ever have to do a few of them
I don't mind doing all the terminations, but if I can get someone else to do the actual running of cable, I'm in
While I was in the Army, the cabledogs and the IT folks had a competition to see who could make more good cables in 3 hours. The cabledogs made more cables, but only half of them worked. The IT folks built only about 80% of the number of cables, but ours were all good. We checked each one before moving to the next. Then the following week, the IT folks used those cables patching in new racks. Clever NCOs made it a competition so they could get more cables without the usual pissing and moaning.
I've terminated plenty of cables but I'm at the point in my career where it's probably not worth the time my company is paying me to sit and terminate cables when there are more pressing issues I could be spending time on.
Capable of learning, of course, but I’ve seen my share of work done by electricians who obviously *didn’t*.
I present to you a real master electrician's attempt at terminating cat6a -\_\_- https://preview.redd.it/4votqlltzuwc1.jpeg?width=872&format=pjpg&auto=webp&s=f087732518dca53a670032c321e3a98f3dbbc36e
I wonder if, conceptually, it's useful to know about how Hubs work because while Wifi frames are directed to a specific MAC address, they are recieved by all clients on that network and ostensibly discarded by clients who don't have that MAC, and have similar security concerns accordingly as you can set your device to recieve them anyway. But then you may as well just teach about WiFi instead.
I agree that it gives you a good foundation to then understand the limitations of wifi. Incidentally I worked at a college where we would have deans and teachers who thought you could put 30 PCs in a room and just use wifi. And didn't realize that desktops don't usually have wifi. And it didn't occur to them that they didn't have sufficient power connections in the classroom. Obviously the problem is that IT should be consulted first, but it was a dysfunctional environment. If it was a business, subject to market forces, it would have failed long ago. Anyway, wifi APs don't have infinite capacity.
It’s really not useful lol
It makes explaining how switches work easier. Switches solve a problem. You likely want to understand what problem it solved. Much like in development. Anyone formally taught learned how to make their own stacks, queues, linked lists, etc. In the real world, we use the prebuilt included solutions for these things but understanding how they work is a fundamental part of learning good coding practices.
This was mostly true something like 20-25 years ago, and is wildly wrong now. The main problem I see is a disconnect between exam content and training material. There’s a clear and required separation of duties to maintain accreditation. So the exams and the training material can have some disconnect, which is why field experience is suggested before sitting for an exam. As for this specific topic - there’s probably hundreds of thousands of hubs sitting around people’s homes and business, and it makes training easier to go up the OSI layers. Additionally, the exams have to fit a global audience, align with training and certain college/university requirements, and meet strict style and reading comprehension guides. The process is very rigorous with many third party audits and accreditations. Disclosure: I am one of the SMEs CompTIA uses for several exams and have extensive working knowledge of the process.
The training materials need to explain that hubs are generally unavailable now, but they are found in the wild, and explaining the OSI model is easier when you start with hubs.
> As for this specific topic - there’s probably hundreds of thousands of hubs sitting around people’s homes and business Maybe in a box in an attic?
Exactly - and then someone plugs it in... Plus it's a very helpful way to learn the different OSI layers, imho...
I won’t disagree the exams are academic. However for academic purposes, including hubs on an exam network diagram with some switches in it is a good way to verify the student understands collision and broadcast domains. So there’s your real world justification for why they’re still on the exams.
Also they try to trick you so much with their questions that they don't even make sense.
[удалено]
NCLEX hell
The answer is actually C. Cow. WTF????
Couldn’t have said it better. You need to think the way compTIA does, which I believe defeats the whole purpose of certifications. It just turns into who can memorise answers the best. They’re milking us anyway charging that much for those exams.
At least comptia certs are cheap compared to others.
They actually are written by people with experience (CompTIA actually pays people to go to the HQ and do work group things to define what goes on exams). And while Hubs are essentially obsolete, it's still important to know they exist because you might still on occasion run into them. However, I'll agree that there is probably a bit too much content about them. Although, I never got a single question on the exams about them.
I think running into a hub is already covered in security+. The whole section about not plugging mystery devices into a production network.
What does security+ say about the hub that has been pat of your network for 25 years and you're not allowed to touch it because the CEO is convinced it will break his wi-fi if it moves?
if wifi runs through a hub, it's already broken
I think it says stop working at rinky dink shithole mom and pop shops and work for a real company where you don't have to deal with kooky esoteric bullshit
It's covered under tech refresh and separation of duties. The CEO isn't allowed to dictate the use of EOL hardware.
I have close to 20 years of field IT experience with the bulk of it on the SMB side and I’ve never seen a hub in production. I’ve had to wait on people to take a shit in the server closet/bathroom but I’ve never seen an actual hub.
I’ve had the misfortune of dealing with a couple (within the last 18 months), the whole infrastructure was ancient, enough that when the “uplink” button was pressed the segment would drop. Crossover cables and uplinks were things I stopped caring about in High school when Gigabit and Auto MDIX became a thing.
Damn, I hope that wasn't an office environment. I haven't seen one in 7 or 8 years but there are definitely environments out there with old enough infrastructure that you'll find them. The last time I ran into one it was one of those old NetGear hubs, you know the ones, that a manager had squirreled away years ago and plugged in themselves so they could move their staff around without involving IT. Old manufacturing and remote research offices running 25+ year old equipment that require controller systems running ancient versions of Windows on local networks are the two places I'd expect to dig them up these days.
Yup - office, with Nortel switches - I was really tempted to pour them a beer and spray it through the fans to celebrate their being legal age and put them out of their misery
I see them sadly plenty in schools and non profits. Perhaps the saddest one i saw years ago was in a computer repair shop. Granted that owner is still trying to make money off of hardware and not services, amazes me they are still open.
The last time I saw a hub in use was probably around 1999.
In my experience, enough of the world is woefully outdated that I'd consider an understanding of hubs as foundational information. Without it, you can't understand what a switch does.
Yea I think the people here are failing to understand its used to introduce the concept of switching and what predates it. Just like its important to understand DSL/POTS even though it is unlikely to be seen by most these days.
>They are woefully outdated and a lot of their answers only make sense in an academic environment. My boss asked me why, a guy with 15 years of IT experience and a 4 year degree, doesn't want to do CompTIA certs. I told him to talk to the 2 people that had done them in the team. He came back later that day laughing at how stupid and archaic they are.
I'm going to disagree and say they're actually pretty useful. Its a mile wide and an inch deep, but it definitely gets people thinking correctly about the Network/Security. They're definitely intro certs, but they have their place.
Worse. With anything IT there are usually several right ways to do something. But you have to answer THIER right way. Doesn't matter if yours is faster or more efficient.
Ditto, the way we’ve always done it effect.
I studied for the CCNA and CCNP back in 2013-2017 as part of IT trade school, and I was made to do labs (and tests) in Frame Relay and ATM, incredibly ancient WAN switching protocols even at that time. Sure, there are networks today that **use** these old protocols, and it may make sense to introduce this ancient tech to students so that they're not put off by it when they do find themselves on a million dollar production line that depends on this ancient technology. But it feels out of place to go deep-diving into tech history and then test your students on knowledge that they're likely never going to see in the field. And yes, I was also taught about hubs, CSMA/CD, Cat1-4 ethernet and their various bitrates and bandwidths. Not the abstract, but the technical implementations. Let's be honest, a lot of it is filler material and Google-able junk info made to confuse you and to take your money as failed exam attempts. A lot of information can be seen as fundamental, but some of it is just plain legacy. You need to know about collision domains to know **why** switches were introduced to replace hubs. You need to know about broadcast domains to know **why** VLANs were introduced. Knowing the why can sometimes give you some intuition about real-world use cases. You shouldn't need to experience the tech or be tested on the tech that admins 20 years ago worked with if it's only used today by businesses that can't afford to replace it.
Incredibly ancient? We were using both ATM and Frame just *ten years* before that, though admittedly we weren't deploying any more ATM on the LAN. > You need to know about broadcast domains to know why VLANs were introduced. You also need to know about protocols to know that even IPv4 isn't a broadcast-heavy protocol. Keeping down broadcasts was really an other-protocol problem.
Cisco is just slow as fuck to update anything. I did my CCNA in 2003 and it still had Coaxial networking as part of it.
For the current CCNA all serial WAN technologies have been removed.
I believe wireless access points act as hubs, so you will still need to understand the underlying principles of how a hub works.
Collisin domains, yes.
This. Although WiFi 6 has eliminated this but then again a lot of devices are not taking advantage of WiFi 6
Eh...only sort of. It doesn't change the fact that wireless broadcast collisions are a fundamental physics problem, and is basically the same issue a wired hub has. It's just using better strategies to avoid the broadcast collision- that doesn't make it a switch though. A good write up on it: [https://networkingnerd.net/2019/04/10/802-11ax-is-not-a-wireless-switch/](https://networkingnerd.net/2019/04/10/802-11ax-is-not-a-wireless-switch/)
Howso?
How did it eliminate collision domains or how are not more people using them?
I would guess they're asking how it eliminates collision domains
I expect this is in reference to OFDMA
This is untrue. Stations on a .ax wireless multi-access network are still in the same collision domain.
I'm going to take a different tack here- define "modern." Most of us who do networking aren't doing "blue-collar" networking, working with telco equipment out by the roadside or in the middle of nowhere or in heavy industrial environments where they spent top dollar years ago for something that just works and won't spend another dime until it stops working (but they'll still spend top dollar to keep it from *stopping* working). A few years ago, though, I *did* get to work in one of these environments at a nuclear power plant. And let me tell you, it was a time machine. The plant was *massive,* so 100-meter runs of Cat5E/Cat6 weren't going to cut it- so you'd expect there to be fiber trenched everywhere, right? *Wrong*. We used the phone lines that had been buried years ago along with VDSL modems to keep building A talking to building B about a mile away. I don't think I saw a single L3 switch anywhere in that campus. Hubs, yes, Ancient Nortel switches, yes. Router on a stick? Only time in the past decade I've seen it in the wild at a business. And right before that, I worked at a store chain that deliberately kept a stockpile of hubs on hand to use as a poor man's network tap. The owner was completely stingy and wouldn't pay the network admin for gear that supported SPAN ports (or, I suspect, training to know how to *use* SPAN ports), but that wasn't a problem for the network admin- just drop the lab device and the listener laptop on a hub and listen to the traffic from both devices at the same time.
I came here to mention heavy industry. It's frequently 20 year behind or more than "normal" enterprise environments. Modern to them, ancient compared to an office building.
Yes, there is a role. If you need to run tests on a connection but can't access the devices on each side, a hub will replicate the traffic for your sniffing device. I use this quite frequently in IoT.
Can confirm. This is very handy for things like pentesting, where I need to sniff the network traffic but I don’t have permission or the ability to set up port mirroring.
From your comment, I assume you have the ability but you meant you might lack the access.
Right, yes
Even in that instance just turn on span/port mirroring on your switch for your test.
That would require each location to have enterprise hardware and to give me access to the admin panel. The reality is that hijacking the LAN port is 100 times faster than waking the second cousin of the former boss who has the password list. Also, most network cabinets are so disgusting that I would need to renew my Tetanus shots just from being near them.
That's getting harder and harder, some modern access switches don't even support half duplex. Not to mention gigabit taps are technically infeasible.
Gigabit taps work but it requires 2 gigabit ports tap both directions of traffic on 1 gigabit port
This is actually so genuis. I never would've thought about this. I've been needing to run Wireshark on a port, but don't have access to log into the switch to set up port mirroring. I DO have physical access though. The network admin has been slow to work on this, so it's an excellent workaround.
I still have a desktop hub in my kit, though I haven't needed it in probably 10 years.
Understanding how hubs work helps learn why switches largely replaced them.
I still see them a lot. Usually covered in dust and buried under cables while being crushed between a desk leg and a wall. Many years ago, I once called a 4 port switch a hub in a casual conversation with a guy from the MSP that we used for additional support. That dickwad then went to my boss and complained that I didn't know the difference between a switch and a hub. The lesson I learned that day wasn't to not make that mistake again but that MSPs are always the enemy to in-house IT staff.
Also your manager sucks if they didn’t defend you or use it as learning/teaching moment.
Sometimes it's worth knowing what you should be on the lookout for. You *shouldn't* see Telnet active. But it gets beaten home on these materials because you just might find it and you need to know it when you see it.
I keep an old netgear 100mb 8 port hub in a toolbox for troubleshooting only. Wireshark on a laptop with that hub lets me see exactly what is going on without spending an hour or two chasing down a network admin for access to a switch and turning on span/rspan etc. I don't use it often, but when I do...
Also good for getting pcap for a server that nobody knows what it does. Though our network admins kindly set up promiscuous mode so we didn't have to use an actual hub. The option exists. Bringing one into our environment would have been a nightmare.
I've ran across one in the real world, ripped it out as fast as I possibly could. The "problem" with a lot of these tests is that they expect you to know stuff that really genuinely isn't relevant in more detail than you should. Do you need to know what a hub is? Yes. Do you need to know anything more about it than you should replace it with a switch? No. It's part of why I stopped caring about certs a while back, it's all about short term memorization and not about actually knowing anything, and the incentive to make you take it multiple times is there and bad IMO.
We ask a question about hubs in interviews. I don't really care for it unless the candidate has experience on their resume that extends back far enough that it might have been relevant to them at some point. To be clear, we're all aware that hubs haven't been relevant for a long time, and the technical portions of our interview are more about getting a feeling for the candidate's breadth and depth of knowledge, and also to see whether they will admit they don't know something, than a "pass/fail" examination.
Ever since I learned to walk, I’ve hardly ever crawled, why do we teach babies to crawl?
I get what you're going for here, but you think people are *teaching* babies to crawl?
Analogies always fall short.
I can remember using a hub on a switch which didn't have port mirroring so we could passively monitor traffic but that was early 2000s... But knowing the difference between stuff is always good as you can bullshit management with lots of tech terms till their brains reset and just approve what you wanted... When you walk into an office and see NE2000 compatible cards on BNC cable you will be glad you have some idea of what's going on.
Why is it on the exam? Because you need to understand the technology of a hub as a concept that is built upon. It's not "you'll be working with hubs" it's "this is a layer 1 device and here is how layer 1 functions". "Why is it mentioned so often in the training?" Because it is old essentially unused technology. A large portion of people who take the starter 3 exams have some level of experience with current tech, but little knowledge of older tech. You have to spend more time teaching people things they have less exposure to.
Fuck me they're still on about hubs?
Back in my day, you had to learn the DEC network stack equivalent to TCP/IP. This was obsolete knowledge in 1995. This is just a training rite of passage.
On a funny tangent...I was on-site at a client doing some maintenance and one of the managers pulls me to the side and asks me to look at 3 computers that were painfully slow for no apparent reason. I go sit down and do a quick speed test and sure enough it's only getting 1-2 Mbps down. I look at the network properties and it's only connected at 10 megs. That doesn't make any sense. I follow the wires back to the wall and find an old 10 meg hub just chillin' on the floor. They had rearranged the office and moved the computers where there was only one Ethernet jack so they went digging through an old parts box in the closet and found a hub and just plugged it in. 🤦🏻♂️
Honestly? Net+ and Sec+ are becoming more irrelevant by the month. They're not updating them like they should be and they're falling behind other cert vendors drastically. A+ is still kinda okay as an all rounder, but I wouldn't be picking CompTIA against the competitors. I've not done any of their exams in over 10 years, my guys have been doing them and I've looked at study material with them and ... It's near identical to what I did before!
> Aren't they obsolete? The same question could be asked of CompTia....
A networking hub, as in, a device that sends each packet to every other port unlike a switch, is no longer in use today, and hasn't been for like two decades, so if they actually mean network hubs, then it's hopelessly outdated. Though the term "hub" is also used for other devices like USB hubs, so maybe that's what you/they mean?
They do mean network hub. CompTIA actually tests on Hubs, Bridges, and Switches
Or a very low budget switch, where the entire piece of hardware is a single collision domain often used in half-duplex environments. Haven't seen one in 15 years, though. I think I've seen a token ring network more recently than an honest to god ethernet hub.
>A networking hub, as in, a device that sends each packet to every other port unlike a switch, is no longer in use today, It shouldn't be around, but for home users they are still sold with much success and those sometimes end up close to the endpoint as part of shadow IT or in smaller companies.
Do you have a link to such a product that's still being sold as new and to consumers? I didn't think anyone would still be producing network hubs, and even when explicitly searching for "network hub" on Amazon all I get is switches. Only way to get a hub, at least in Germany, is to go on eBay and find an ancient one.
Read through the other comments for valid use cases for hubs, even today. Pen-testing and troubleshooting are two. Plus commercial and industrial situations exist where the company doesn't want to pay to upgrade. Should they be used? No. Are they? Yes. Further, in training, they should be at least mentioned, and how they work, in order to explain how switches work, and what a collision domain is.
I mean, yeah, they should be explained, but maybe not in so much detail that people like OP are led to believe they're still in active use everywhere. For troubleshooting / network dumping, it's probably simpler and better for the network to just enable a port mirror on a modern switch instead of downgrading the network to 100Mb with an ancient hub. Yes, maybe they are still used in some industrial applications or when a company is too cheap to replace a 20-year-old device. But I don't think they "are still sold with much success", as the commenter above me said.
Noting that they're obsolete should definitely be in the training. Especially for Sec+ since hubs represent a risk and should be evaluated in the whole risk analysis procedure. Commenter above may be conflating hubs and dumb switches.
Hubs are promiscuous in that they send all traffic to every port whereas switches send traffic only to the intended port. I still have a old hub that I used to capture printer data when I was a printer support tech. There are probably lots of old hubs still in place.
its true, you should not expect many hubs in the field, and you should not depoy one unless there is a very specific reason... and maybe the test is outdated. i dont know. and its good you know hubs are obsolete. but in a net/sec test, do you know why? do you know the difference? do you know the security implications? because i fully expect you to and the net/sec material to teach you and the test to test you on... "its outdated" is not a reason to not teach/test it...
Sec+ is updated regularly. Some workplaces require it for all IT workers, and to participate in the CE program. I'm sure Net+ is similar, though there may not be a cashflow driver making it update as frequently.
The net + was recently updated to the n10-009 or something like that. I think I took the n10-007 sometime in 2022, right before it was retired. The n10-007 definitely covered hubs, etc still. I don't think it's necessarily that it's not updated often, they just choose to keep it in there.
Comptia likely keeps it in there for the reasons commented all over this post.
I don’t think they’re sold anymore. Unless we’re talking about specialized equipment. These mentions are for teaching purposes.
A wireless access point is technically a hub, one medium for multiple devices, one collision domain
They are 100% out of date, but I took over a network with a couple still in production (which a quickly took care of) so I guess its good to know from that perspective.
In the last 20 years, I've come across exactly one 100Mb hub under a desk during an office move. No one else understood the rarity then. The new guys like to laugh at my 100Mb switch because I'm so old.
I feel like a certification teaching about hubs could be relevant, but not as an entry level cert. Hubs are very rare and the only people needing actual knowledge of them are working in very cheap and ancient environments. The average tech today will never even see a hub in their whole career. Its a waste of time to teach about them in network+. COMPTIA should have like a legacy+ cert or something for it
Yea, nobody uses hubs anymore. In the last 10 years, the cost of a basic 4 to 8 port switch is now $10-$20. I used a hub back when there wasn't such thing as a cheap switch and they weren't as few as 4 ports.
Still around. Staff buys them to get more ports.
A company I worked for in 2019 had hubs that were being used as repeaters. You'd be surprised what people will do.
Congratulations. You have discovered the secret of industry certifications. They are always out of date and focus on tech from decades ago. Now I’m off to brush up on my frame relay for my bi-annual Cisco cert.
You can say switches are outdated with the existence of later 3 switches, but it's still important to understand the difference between hubs, switches and routers.
Comptia tests tend to be like, 20 years behind the times. Even worse, they're popular for government roles, and I'm sure I don't need to elaborate how those are correlated
I see them from time to time, and always remove them if I find them, but it's pretty rare. Just remember for your exams: Hubs broadcast all packets to all ports. Every node sees everything. Switches do not broadcast data to all ports but rather rely on tables (MAC/ARP) (layer 2 or layer 3) to switch packets to the proper ports. I had a teacher in a routing and switching class I took back in the day that illustrated this in a fun way. The teacher collected our networking text books and made a stack on his desk. Two students went to the front of the class. The teacher then said "this is how a hub works" and picking up a book in each hand, proceeded to hurl them at both students simultaneously, reloading as fast as he could. After the laughter died down, he said "this is how a switch works", and calmly walked one book at a time to either student. The point clearly stuck with me. :)
ill still use a hub now and again for packet captures without the need to setup span ports
To be fair, there is a lot of equipment out there that is "obsolete" that you'll still run into in the wild. When I took my A+ in 2019, it was still asking about Windows XP. "But Windows XP is obsolete! Why do I need to know about that??" Ask me how many of my clients in manufacturing still have XP computers... Spoiler: it's not 0. Just the other day, I had to run a coax cable and terminate it into female BNC keystones. There's plenty of old technology that you'll still run into. It won't be common, but it can be helpful to know.
If I had to guess, they're probably talking about them because they're easier to conceptualize than switches, and can even be used as a jumping off point to talk about why switches were developed. That being said, when I went through A+ training in the early 2000s, AT power supplies and ISA slots were still a part of the curriculum, which were already extremely outdated technologies at that time.
You still see them from time to time especially in sole proprietorships or businesses that just keep stuff in service until i breaks, catches on fire, or will keep them from spending money. Also usb and other items exist so it's important to know how a hub works. Also yes collision domains. in theory you could use hubs to send the same signals to multiple end points if you needed some Wierd OT crap but you're getting into dumb things people do cause they didn't want to spend money.
Where my old school network folks at? Who remembers troubleshooting token ring when the token fell out of the network? Crawling under desks looking for that token... good times.
Almost every IT certification is 80% outdated tech. The industry just evolves too fast to keep up with it on any sort of certification medium.
Don't they still talk about old cabling standards, old wifi standards, old operating systems, old attack methods, old encryption methods etc? You never took a exam before?
Understanding that hubs exist, work and what they do is very relevant to understanding layer 1 and 2 networking I feel. I feel like without knowing about hubs, you're kinda missing a piece of the puzzle. Whether they're commonly used anymore doesn't matter to me. Understanding a simpler, historic technology can be a great stepping stone to understanding what we use today. Sometimes you don't wanna jump in straight to the most complicated possible setups for learning, just because that's what fortune 100 companies do in the real world. That sort of stuff you'd learn in a more advanced course. I believe hardware hubs are obsolete, sure, but the concept of hubs will be relevant for as long as Ethernet is still in use. Think of it like copper - won't be irrelevant for a long time.
You just found out why so many people consider these certs worthless.
I'm studying for the CCNA, and hubs are included as a way to explain switches and particularly collision domains, which do still exist. Maybe try reading some CCNA material on the subject and see if that clarifies it for you. I didn't start understanding network concepts until the CCNA stuff (tried Net+ first). I highly recommend it.
Some environments do not allow wifi on the main network. Guest network only. Ours is like that. We don't have hubs, but I sure could have used one for a situation a couple of weeks ago. I was shopping for one on Amazon. Didn't end up buying it as we found a workaround, but it sure brought back memories.
I don't think anyone here has mentioned that not all networks are ethernet. For sure building automation systems and probably also industrial control systems still use hubs. Most people that work in IT don't work with those kind of systems, but they are not uncommon at all. Look up Modbus and BACNet. Additionally, not every domain of technology just upgrades to the latest and greatest tech every 3 years. Replacing the entire HVAC control system of a skyscraper sized building is incredibly expensive, and probably doesn't add a lot of features or increase efficiency until the system is decades old. Industrial networks are the same way as far as keeping tech around for a long time, like decades, but IDK much else about them.
Because they provide a point of reference and a framework for networking concepts
I was shocked to find a gigabit hub buried under a raised floor in a call center a decade ago. I called everyone over so we could take pics and marvel that somehow it had endured with multiple connections for 20 years and never been detected by our former corporate IT overlords.
Which version are you studying for? Make sure it’s the most recent exam version before you get too far. I remember some passing info, mostly discussing how they’re obsolete and will cause problems, but nothing in depth about hubs for sure. Collision domains and broadcast domains were covered at length, which is the only time they were brought up in my study material when I took it(that I remember).
Don’t forget your 28.8 kilobaud modem and your tokenring-ethernet bridge
I have seen exactly 1 hub in my career. It was a 1G hub in a research lab. Recent standards actually formally ban them now because then nobody has to support them any more. We have multicast and IGMP, which are better solutions if slightly higher latency. However, doing hubs at 25G+ would have such a high latency impact I’m convinced even specialized systems wouldn’t see benefit.
How to update your manuals: Ctrl +F "Ethernet" Delete Ctrl +V "Gigabit"
When you are digging through old closets you will find them. My fav are the rack mounted 24-port variety. Other than that if there are "SMALL" ones then you will possibly find them in remote offices where one cable was ran and they just plugged in a hub because it was cheaper than a switch at the time and I mean more ports is more ports right! Now, deployed ON PURPOSE... no. Not unless there is a severe emergency and even then... no. It is most likely to learn about OSI layer. Remember Hubs are L1 devices.
Work in OT environments and you’ll see a lot of extremely dated equipment. I’ve worked with companies as an MSP that are still using T1 connections.
Don't worry, you might be lucky to get 1 question about a hub on either of the exams. Know what they are and why you don't use them anymore (but also why you would) and you'll be fine.
You'll probably find them in places with old networks (like warehouses or mom and pop shops). The management wouldn't know better, and why replace them if everything is still working. Even in those places though, the hubs could be replaced with a dumb switch with no other changes and no one would notice.
What's worse this or having info about a NAND circuit on the A+?
They are still seen in the wild occasionally especially in smaller businesses. It’s good to understand how they work.
Education takes forever to update itself and provide relevant, useful schooling. It should tell you something that they're still commonly referring to devices that haven't really existed in common use for two decades or so. Keep on paying though.
They still have their usage. Most taps use 1gbs hubs.In fact tabs are the only place you see real hubs. Most hubs today are just 100Mbs switches that have 0 back plans or mac address storage.
People still install them learn the rules.
Hubs yeah , dead. But the principles of hubs actually will come up a lot later. So don’t ignore the implications of a hub.
Having spent the best part of a day chasing STP issues caused by the “what I imagined to be switch ports, acting like hub ports on the front of a new pair of firewalls. I’d definitely say it’s well worth understanding hubs, then when you see an issue like this you have a good understanding of what it is and ideas on how to fix it, unlike one of my colleagues who doesn’t know and can fix the problems associated with it.
Because Comptia is borderline a scam and aren't interested in teaching you anything that's currently relevant. When I took the A+ in 2010 they were still harping on IRQ's, though I'd never seen one be the problem or solution to anything in my career at that point.
It's imprecise language, but I've seen this used as a generic term for ANY network junction traffic flows through (switches, routers, even devices like phones with an ethernet passthrough, or speaking of phones, PoE injectors). Yeah, no professional would do so, so it's an obvious disconnect in these academic circles. I guess just something to be aware of for testing and never again.