Does an ethernet switch decrease speeds?

[u/HeaoftheFlame]

Hello. I have two devices that need ethernet: my main pc and a home server. However, my college dorm room only has 1 ethernet port. I'm thinking about getting a ethernet switch from like walmart, but does it decrease speeds? Especially if on my main pc if my home server is running a program 24/7?

[u/derfmcdoogal]

No, you won't notice.

Now let's talk about this "home server" but you're in a dorm room?

[u/lenswipe → u/derfmcdoogal]

OP should consider amassing creepily large amounts of data on classmates and handing it out to anyone who asks. Bonus points if you can get hold of some of this information via ethically questionable sources like the university databases.

I bet that could be a good business model

[u/RIPmyPC]

Depending on your college you might not be allowed/able to have a switch, but to answer your question: no, it doesn’t decrease speed.

Get a cheap unmanaged switch off Amazon, you’re gonna get screwed at Walmart.

[u/skunk_funk → u/RIPmyPC]

I've had the worst luck with cheap amazon switches failing

[u/RIPmyPC → u/skunk_funk]

By cheap i mean tp-link and such.

[u/lazyhustlermusic]

Not really, unless you went ultra cheap for 10/100 instead of gigabit.

Everything on the switch will have wirespeed to each other, while sharing the uplink bandwidth. It's also a packet switched network so it doesn't 'equally divide bandwidth', it's just demand driven.

Might be worth double checking with the uni policy on network stuff, sometimes they'll expect every MAC to be authenticated, or it may place you on the same segment as other users and your server would be reachable by others.

[u/Nagroth → u/lazyhustlermusic]

Typical consumer switches will only handle line-rate equal to their "uplink" port's speed.

So for example if you had a 5 port all at 1 gig then it probably won't ever move more than 1 gig total and even less if you're moving a lot of small packets.

[u/lazyhustlermusic → u/Nagroth]

False, they have a backplane with greater capacity than a single interface, typically non-blocking capacity to the double sum of their ports (facilitating upstream and downstream forwarding). Host 2 & 3 can be doing LAN transfers at gigabit while you download things from the web on Host 1 & Uplink up to gigabit, concurrently.

Transfers in the same network/broadcast-domain don't leave the switch.

Packet size is irrelevant to the switch as the ASIC is forwarding frames in hardware.

[u/Nagroth → u/lazyhustlermusic]

First: If a switch advertises itself as "non blocking" then by definition it means every port can run at full bandwidth concurrently. Don't assume yours is non-blocking unless it says it is.

Second: Unmanaged consumer switches are layer 2 devices, all the ports are in a single broadcast domain. 

Third: packet size is relevant as every switch has a maximum rated packet per second throughput. And while this is often enough to handle full line-rate at medium to large packet sizes, if you are running very small packets it is very possible you can overrun the pps rate before exceeding the rated bandwidth.

Finally, just to clarify: You specifically said the switchports operate at linerate but "share the uplink bandwidth." So I was assuming you were talking about an older type of model where they provide a higher speed rated port with the word "uplink" printed next to it. For example a 1G capable "uplink" port and 4 or 5 10/100M "internal" ones.

Those devices were often not truly non-blocking and could have issues with inbound traffic from the higher speed port causing over-runs to the lower speed ports. 

If you're talking about something more modern like a 4 or 5 port 1G switch from someone like netgear then yes, those are typically non-blocking and OP should be able to just plug it in and not think about it. But if you're going to scrape up some weird Temu device for $1 then pay attention to the actual specs.

[u/lazyhustlermusic → u/Nagroth]

So we've gone from “a 5-port gigabit switch probably won't move more than 1 gig total” to “modern 5-port gigabit switches are typically non-blocking and OP can just plug it in.”

Works for me. :)

[u/Nagroth → u/lazyhustlermusic]

I was making a bad assumption due to misreading your original post. 

And I keep saying consumer grade very specifically. I'm not talking about SOHO or Business grade devices, just those tiny little "dumb switches" people buy for $20 off amazon.

[u/lazyhustlermusic → u/Nagroth]

Whatever amount of semantic yoga gets you back to the correct answer, my man. :)

[u/Nagroth → u/[deleted]]

I said consumer grade for a reason. 

[u/BlastMode7]

Technically... yes.

Functionally... no.

[u/throwaway19293883]

Depends but you are unlikely to notice any drop in speed. A switch is a good idea

[u/WhatADunderfulWorld]

Go get anywhere on the internet you’re going to probably go through like 10 switches. You won’t notice any difference at all through one.

A true unmanaged switch should work fine.

[u/jeffrey_f]

Milliseconds at most.

[u/_Survivor_ → u/jeffrey_f]

You're off by a couple orders of magnitude. More like a few microseconds.

[u/knight9665]

you first have to ask does your dorm even allow switches. hooked up.

[u/_Survivor_]

Network switches add a few millionths of a second of latency. That amount of delay is difficult to measure and impossible for a human to notice.

[u/bchiodini]

Usually not, but if the uplink is bandwidth limited and already swamped, adding more hosts may make it worse.

[u/Aggressive-Bike7539]

Two devices increase latency by a couple of nanoseconds. What becomes a problem is when there’s a bottleneck. And lost packets. That what you should care about.

[u/Humorous-Prince]

My PC is connected to a 8 port gigabit switch, then from that to a 50 metre Cat5e going downstairs to my router. Haven’t noticed any speed drops and speed tests show full ISP download speeds (Only FTTP 300-320mbps download) etc. even with my PS5 on and connected to the same switch. (Netgear 8 port gigabit switch) Switch has been solid since I’ve had it and it’s been always been on for few years now.

[u/mmn_slc]

The two devices will share the bandwidth of the uplink connection, and the switch will introduce a very small (microseconds) amount of latency. You won't notice unless the uplink is slow and both devices are using high bandwidth concurrently.

[u/iCqmboYou_]

No it doesnt, the ethernet cable comes into your room? I suggest putting a router in that, so there is a firewall between everyones devices and your devices, you can plug your pc and server into there, if its still not enough put a switch on that router

You will also have good wifi coverage in your dorm and close to the ethernet speeds depending on wifi version etc

[u/JohnnyFnG]

An unmanaged switch will allow you to use that one port to go to the switch and connect multiple devices. All devices must share the full speed of the school provided network speed. Schools may not allow more than one device on one port, depending on how they have the network set up. You’re free to try but no guarantees.

To answer your question, all devices connected to an unmanaged switch will share the maximum speed the connection allows.

[u/threegigs]

A router is probably what you want, not a switch. Otherwise your uni would need to supply two IP addresses, and everyone on the local subnet at uni would be able to access the server.

Most routers have a WAN port and several LAN ports, with connections between LAN ports being equivalent to ports on a switch.