How are they able to support thousands of users at one time? I do a speed test and they aren’t like fiber optics level of speeds so how can they have so many users at one time? Is it because there are so many routers placed around the area? But even when I’m on campus I don’t see any wireless routers outside.
In: 249
Fiber that literally goes just to that place.
They are one careless excavator away from not having internet.
EDIT: I should say from having *enough* internet
Here in the UK, large enough universities and research insitutes use something called JANET. Its a high speed dedicated network which connects directly to the backbone of the Internet
JANET currently supports up to 2 terrabits a second.
But a lot of places are using their 100 gig connections.
This is by far plenty for large organisations.
There’s a big point that I don’t see in the other answers.
Most users aren’t using any bandwidth at a given time. You share one or more uplinks to the internet. That’s most probably 10Gigabit or much more.
When you do bulk business for thousands of end users you get very good prices. Especially if your organization can handle the local network and support themselves.
Fibers (actually digging them into the ground) is expensive, paying employees in the support is expensive. Bandwidth is cheap.
Just like water is cheap, but not in the desert.
> How are they able to support thousands of users at one time? I do a speed test and they aren’t like fiber optics level of speeds so how can they have so many users at one time
So, first thing is, most people aren’t using much – or any – bandwidth most of the time. A 10Gb/s connection will comfortably support 10,000 normal users, and the university will likely have various caching servers running as well, so if you think you’re downloading updates from Microsoft or Steam, there’s a fair chance it’s being served from a local cache on campus.
The exception here is if the university has some serious science equipment – like radio astronomy or particle accelerators which generate epic quantities of data. These will have their own private links to whatever computational cluster or data store supports those instruments, but the university may then have invested money in beefier internet connections for partners at other institutions to access that data – in which case you start moving from 10G into 40-100G connections. Many countries also have academic networks such as [JANET](https://en.wikipedia.org/wiki/JANET) or [GÉANT](https://en.wikipedia.org/wiki/G%C3%89ANT) linking universities for this purpose. The links are usually dedicated fibre – not the public internet. So the university may have a “general” 1Gb or 10Gb connection to a transit provider onto the general internet, and then a >10Gb connection to JANET/GÉANT/etc. 100G interfaces are now becoming pretty common as hardware is upgraded. Depending on the nature of the institution and how much inter-university traffic they’re doing, it could be that the “many tens of gigabits of outbound connectivity” is almost entirely connections to the academic networks with only a very small transit connection to the wider internet.
Now, as to why *you* can’t see those sorts of speeds when you run a speed test, there are a bunch of possibilities:
* Your device is incapable of supporting those speeds (especially if it’s over wireless – you will be capped by the wireless throughput of the link).
* Your local node is congested – even if you have a laptop plugged into a Gb ethernet port, that only means you’ve got Gb to the switch. There’s nothing to say that the switch on your floor of your building is able to pass that much data through to the campus core router (or even the main aggregation switch in your building) and onto the internet. You are competing for bandwidth with everyone on your floor, in your building and then on campus.
* You are throttled as a user. If you’re accessing the network as a guest, you’ll probably get lower speeds than if you are authenticated on the network – and even as an authenticated user you may be limited to prevent any one person hogging resource. I’ve seen exactly this in a government building where I as a guest could get 300Mb/s on a speed test, but my host – on a computer sat next to us (signed in with her staff account) could get 700Mb/s. Sysadmins will always give themselves lots of capacity. Staff with requirements (like astronomers shunting big data around) will have enhanced privileges. The accounts department working in Sage and Excel will have a much lower limit, same for undergrads.
* Your connection is being managed by Quality of Service tools. There’s a tonne of ways to rate-limit types of traffic. For instance if someone is trying to download a multi-GB file, that’s not particularly time (latency) sensitive. It’ll get throttled so that it doesn’t interfere with the phones (VoIP) or audio/video streaming which *are* latency sensitive (you’ll notice if they start skipping). Your download might take 7 minutes instead of 5, but that’s not really a problem. Email can also wait – it doesn’t really matter if an email goes in a second or gets queued and goes 5 minutes later. Speed-testing – when detected – gets hammered, and even if it successfully disguises itself as something else, will get managed and throttled in accordance with set policy.
A. Campuses/large properties will usually have a 10G connection (or a couple 10G connections for failover and backup). You’d be surprised at how little traffic is really used on a campus of 10,000 students or so.
B. Each building usually has a network room with multiple switches with a fiber backbone back to the main network room where all the routers/firewalls/servers are located.
C. Wifi access points are usually high capacity for 200-500 people and powered down lower so they don’t send a signal out as far, thus you have to have more Access Points spaced out around buildings to provide a decent connection.
D. They meter the connection, meaning for each person online, that person can only use up to 100mbps (on a hardwire connection) and 25mbps (on wifi). That way a bad actor will be sufficiently stopped to not take up much bandwidth.
The fact that we have slow internet in the first place is insane. The USA paid Verizon $400 billion near 2000 to provide gigabit speed across the country and they just didn’t. Now they are charging insane rates to provide select locations those speeds.
ELI5: It’s very easy to provide that kind of bandwidth. We just don’t because internet providers in the USA are greedy fucks.
how is this question allowed? surely it breaks Rule 2?
There aren’t routers placed all over the place but you are close.
Those are access points. Their only goal is to connect people to the wifi. Then the reason they are able to get so much bandwidth is segmentation. Those access points aren’t all hooked up to a single location. They are going to be hooking up to several network switches throughout the school. Then those network switches will have an extremely high speed connection back to “the core”
Then the core is likely connected to redundant internet connections. When I did networking for my college they had three separate providers, one for a specific project for a single building but then the other two they had one maining as business and staff traffic and one for student traffic where if one failed the traffic on the failed connection would fail over to the backup connection. They are also paying for much higher bandwidth than you can find for home use. Business connections have much higher data rates than home connections so you may be looking at 100Gb where a home connection, depending on where you live, may cap out at just 1 or 1.5Gb.
So your phone is connecting to the access point with say 20 other people and hitting a 100Mb connection. Then it hits the switch and suddenly there’s 400 peoples data hitting the switch but that’s okay because the switch is communicating to the core with a 10Gb connection. Then your data hits the core and it’s competing with 4000 peoples data. That’s okay though because it’s being sent to the Internet Service Provider (ISP) with only half of those peoples data on a 100Gb connection.
So, the backbone of a large network like that is usually a *switch*, not a router. The main difference is that a switch functions more like a straight up splitter, kinda like those headphone splitters you can use to share with someone else, but a bit more complicated. A router actually creates an isolated network between a set of devices, and provides a gateway for all of them to access the internet, or a larger network, switches just propagate the existing network. Also, switches usually aren’t wireless.
Another key difference between a switch and a router is that switches are usually much bigger and can handle a lot more traffic passing through them. Typically, a switch will have between 24 and 48 ethernet ports, and usually 2-4 uplink ports that could be either ethernet or fiber, usually fiber. Those uplink ports are typically a lot faster, can handle more bandwidth, and they’re used to connect to other switches or to whatever the gateway device may be. Usually the gateway device is a firewall that sits between the campus’s internal network and the internet, and allows the campus networking department to monitor & control the flow of data in and out of the network.
Switches are fairly large devices, and are quite expensive, so it is very common for them to be mounted in locations that are secure and out of sight. They can be put above drop ceilings, in maintenance closets, or in boxes mounted close to the ceiling. If you see a black box close to the ceiling with a bundle of about 30-50 blue cables going up into the ceiling, that’s most likely a switch.
Many campuses also connect wifi access points to the switches, in order to provide wireless access to the network for laptops, tablets, and mobile devices. Most buildings will have at least one switch to serve as the hub for the whole building, and will connect others to it as needed. You might have one per floor for classrooms, or one per room for offices & computer labs. Another thing that’s common in campus buildings is to run ethernet through the walls just like the electricity, and those connections all go back to a switch somewhere.
You also probably won’t see switches outside, fiber links can run for several miles. It’s pretty common to connect the switches in the building to a switch that’s usually in the campus’s main server room. Those lines are usually either run underground, or along telephone poles.
The main uplink for the whole campus is most likely going to be an extreemly high speed, high bandwidth fiber link that goes out to the internet, and they pay a pretty high premium for that kind of connection.
Now, the reason why your speed test isn’t getting “fiber speeds” is because your bandwidth is probably being throttled by the switch. Most modern switches are “managed” which means they can be remotely accessed. You can canfigure them to only allow specific devices to connect, limit how much bandwidth each port can use, see what devices are connected, and you can even disable ports.
If you want a good idea of what all this looks like in practice, i suggest having a look at r/cableporn. Pics of switch racks and large cable runs get posted there pretty regularly.
Your speed test does not reflect the bandwidth available at the campus, it reflects whatever the network decided to allow you to have at that moment through the various proxies and network infrastructure, both physical and virtual that your traffic passes through.
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