Crumb
c/networking · by ChocolateFrostedSugarBombs@lemmy.world · 11d

Not getting the speeds on LAN I should be.

EDIT: Thank you everyone who responded. I am dumb dumb and was getting confused on the conversion from 1 Ggiabit to 100 Megabyte. To throw another wrench in the works, I had made a typo in my original post but it ended up not being impactful. I meant to write my speed was limited to 100 MiB (Mebibyte) but again I was confused here because I was reading that as 100 Mib (Mebibit)

So anyways, thank you all who chimed in. Apologies for my dumb.

Hey everyone,

I've been trying to troubleshoot this issue for a while now. Here's my setup:

I have CAT 6a cables in my walls, should support 10G. I have a Cisco C1300 Switch connecting them. Each port on the C1300 is 10G.

I have a Synology NAS on my LAN that has a 1G LAN port. My laptop has a 1G LAN.

Now I know these speeds are theoretical and I'll never actually reach those speeds. But the issue I'm running into is that everything on my network seems to operate at a max of 100MB/s. All settings on the C1300 show that they've negotiated at 1G. So what am I doing that limits data transfer to 100?

I'm also getting limited to 100MB when I try to download something like from Steam but I understand that adds a lot of additional things that could cause the issue so for now I'm just focusing on my LAN. It's just odd that even WAN speeds appear to be limited to the same speed as my internal.

Does anyone have any ideas of what I could check or what I may have misconfigured?

6 points · 6 comments · view on lemmy.world

6 Comments

frongt@lemmy.zip · 21 pts · 11d

Yup that sounds right. A gigabit link runs about 800 megabit in reality due to overhead (ethernet frames, tcp headers, etc.). And 800 megabit is 100 megabyte. So you're getting full gigabit speed, congrats!

ms_lane@lemmy.world · 12 pts · 11d

8 bits = 1 byte

1 Gigabit == 125Megabytes

With overheads, ~100MB/s is right, you can get close to 120MB/s if you use jumbo frames, but you'll get worse internet latency as frames going to 1500/1492 MTU internet will fragment.

0x0@infosec.pub · 3 pts · 11d

I have a Cisco C1300 Switch connecting them.

Connecting what..?

If your devices are 1G your switch could be 40g, it still wont go higher than 1

hydrashok@sh.itjust.works · 1 pts · 11d

If I understand, you see everything showing connected at 1000/Full, but are only getting 100/Full speed?

After validating the cables are terminated and tested successfully with a cable tester, I would try explicitly setting the speed and duplex on both the switch and client and retesting. Sometimes auto negotiate sucks at its job.

artwork@lemmy.world · 1 pts · 11d

Wonderful day!

Just in case, are you sure all the wires inside the cables are health? A damaged cable may cause the lower speed, by standard.

Gigabit Ethernet requires all 8 wires inside the cable to be intact and properly connected, whereas 100 Mbps only uses 4 wires. If there is a loose or damaged wire inside the cable, the connection will fall back to 100 Mbps to maintain link stability. Even if the cable previously worked at gigabit speeds, physical damage like rolling over it with a chair, stepping on it, or pinching it in a door can cause this issue.

Source

Does the same speed appear while connected to the ISP directly?
I would also try drawing a scheme for such a question, for others, and then test each connection separately, with at least a basic Ethernet cable tester like the following:
- https://ascentoptics.com/blog/cable-tester

artwork@lemmy.world · 0 pts · 11d
[ removed ]
Onomatopoeia@lemmy.cafe · -1 pts · 11d

How do you know what your file transfer speeds are (network speeds)?

If the switch thinks links are 1G, then the links are 1G.

Where are you seeing slow network performance, and how are you measuring it?