| 21 May 2025 |
 magic_rb | It depends on the sfp module not switch | 12:18:33 |
 matthewcroughan - nix.zone | So if I plugged the rj45 side of a 10G SFP cat6 setup into a 2.5gbps port on my laptop, it's not going to work unless the SFP I have chosen supports "negotiation" | 12:19:27 |
 emily | well, it can depend on both | 12:19:31 |
| emily | some SFP+ modules will do 10G on the host but negotiate multi-gig | 12:19:39 |
| emily | some of them will negotiate slower rates on the host too | 12:19:47 |
| emily | I'm actually busy looking for the perfect Broadcom SFP+ module right now but it's easy to find ones that just do 10G always if that's what the switch want | 12:20:06 |
| emily | * I'm actually busy looking for the perfect Broadcom SFP+ module right now but it's easy to find ones that just do 10G always if that's what the switch wants | 12:20:07 |
| emily | it's pretty easy to find people talking about what they'll negotiate online anyway | 12:20:35 |
| matthewcroughan - nix.zone | Yeah the issue is that the laptop things are plugging into will vary from 1/2.5/5 | 12:20:38 |
| matthewcroughan - nix.zone | and then if someone comes in with their mega dongles like you, I suppose 10 is possible | 12:21:05 |
| matthewcroughan - nix.zone | https://www.amazon.co.uk/QSFPTEK-10GBASE-T-Transceiver-SFP-10G-T-S-UF-RJ45-10G/dp/B081YKGBR4 | 12:23:40 |
| matthewcroughan - nix.zone | this one says in the title "1.25/2.5/5/10G-T Copper Module SFP+ " | 12:23:54 |
| matthewcroughan - nix.zone | So I assume this means negotiation is possible | 12:24:01 |
| matthewcroughan - nix.zone | That's one expensive SFP though | 12:25:16 |
| emily | again you want to be looking at aliexpress | 12:42:00 |
| emily | and not at 30 m ones | 12:42:04 |
| emily | and at multipacks | 12:42:10 |
| emily | also you can always just buy mostly <10G ones if you expect most users to not use 10G | 12:44:07 |
| matthewcroughan - nix.zone | 5G being an awkward number, is that really an option? | 13:02:00 |
| emily | what do you mean? | 13:02:14 |
| matthewcroughan - nix.zone | Like, are 5G SFPs really a thing? | 13:02:41 |
| matthewcroughan - nix.zone | god, it is | 13:02:53 |
| emily | sure | 13:03:02 |
| matthewcroughan - nix.zone | Only hard though without auto-negotiation | 13:03:10 |
| matthewcroughan - nix.zone | if I do this trick though, I'll need 8 SFPs, for plugging into the 8 port SFP switch, which could get quite expensive | 13:03:43 |
| matthewcroughan - nix.zone | whereas the less versatile setup of using that weirdo 10G SFP input 6x 10GbE output switch is only 120 quid | 13:04:28 |
| matthewcroughan - nix.zone | * whereas the less versatile setup of using that weirdo 10G SFP input 6x 10GbE output switch is only 120 quid, and don't need to buy these expensive SFPs | 13:04:38 |
| emily | there are cheap ones esp if you buy multiple at once | 13:08:09 |
 antifuchs | the main issue with SFP->ethernet modules tends to be heat... those modules specifically get very warm | 13:10:19 |
| emily | not the ones with the Broadcom chip :) | 13:11:41 |
