10Gb/s 이더넷, 브로드컴 SFP+ 모듈 전환

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    게시일: 6월 16일 [2026년](https://www.gilesthomas.com/2026/06/)  
    
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Back in April 10g-ethernet-what-i-did, I upgraded my home LAN to 10Gb/s.
The in‑wall cabling is CAT‑6 or similar, so I had to use 10GBASE‑T. Now, the router I’m using and the switch in my study provide 10Gb/s through SFP+ cages; that meant they needed 10GBASE‑T SFP+ modules to connect.

That kind of module is known to run hot — sometimes too hot to actually work. The modules in reggie, the router, appeared to be running OK (see the linked post above for charts), but the one in nigel, the study switch, was a worrying 93 °C. I tried sticking some mini‑heatsinks on it, which seemed to help a bit. But the weather got warmer, and eventually the module overheated. I lost access to the Internet from the study, and checking the metrics showed me this:

Nigel의 10GBASE‑T SFP+ 모듈 플래핑

You can see that it’s “flapping”: the temperature rises to a level where the module shuts itself down for protection — about 95 °C, I think — and then when it recovers, it powers on again, the temperature climbs, and the cycle repeats.

I was able to work around the problem by turning on the air‑conditioning in the study. But normally I only have it on when I’m inside, and keeping the AC running 24/7 just to keep the network working felt like the wrong solution.

It was time to switch to a more power‑efficient SFP+ module.

My original 10 Gb/s post had quite a lot of discussion on Hacker News, and xxpor mentioned that there are two generations of 10GBASE‑T SFP+ modules: old ones using a Marvell chip, and newer ones using one from Broadcom. blunden on the ServeTheHome forums made the same point. The Marvell‑based ones were known to run hot, and they both recommended finding Broadcom‑based ones.

I confirmed that the MikroTik S+RJ10 I had in nigel was indeed a Marvell model, so the solution was simple: get a better one. I ordered a 10Gtek ASF‑10G‑T80‑INT. Checking 10Gtek’s own page on that module confirmed it uses the correct chip (though the description was a bit garbled):

10Gtek’s ASF‑10G‑T80 is the newest copper transceiver version; its biggest features are ultra‑low power consumption and longer transmission distance (1.6 W at 10 Gbps over 30 m, 2.0 W at 110 Gbps over 80 m). It’s a 10GBASE multirate copper RJ45 SFP+ transceiver designed with the Broadcom BCM84891 PHY, following IEEE 802.3an/az and SFP+ MSA specifications, supporting up to 80 m over CAT‑6A or CAT‑7.

A day or two later it arrived, packaged in a rather pretty little metal case:

Installation took a little while because removing the existing MikroTik module was tricky; Willie Howe’s video on YouTube helped a lot by showing how to disengage the latch, though I still had to fiddle with it quite a bit to get it out.

Eventually that was done, and the new module went in. I plugged all network cables back in, switched on the switch, and (after a slightly nerve‑wracking wait for it to boot) the network was back up and running!

So, were the temperatures any better? I checked my monitoring, and:

H Nigel의 10GBASE‑T SFP+ 모듈: 온도가 보고되지 않음

Huh, nothing was being reported.

That makes sense. The way I charted those numbers was that the switch exposed them via SNMP, then the Telegraf daemon on my router, reggie, read the values and sent them to InfluxDB; finally, Grafana did the charting.

I’d been reading the module temperatures using the SNMP OID I identified as providing them from the switch (.1.3.6.1.4.1.14988.1.1.19.1.1.6.3 if you’re interested), but perhaps the new module uses a different OID. It was time to log in to the switch and take a look.

[admin@Nigel] > /interface ethernet monitor sfp- sfpplus1 once
name: sfp- sfpplus1
status: link- ok
auto- negotiation: done
rate: 10Gbps
full-duplex: yes
tx-flow-control: yes
rx-flow-control: yes
supported: 10M-baseT-half
10M-baseT-full
100M-baseT-half
100M-baseT-full
1G- baseT-half
1G- baseT-full
1G- baseX
2.5G- baseT
2.5G- baseX
5G- baseT
10G- baseT
10G- baseSR-LR
10G- baseCR
sfp-supported: 1G-baseX
10G-baseSR-LR
advertising: 1G-baseX
10G-baseSR-LR
link-partner-advertising:
sfp-module-present: yes
sfp-rx-loss: no
sfp-tx-fault: no
sfp-type: SFP/SFP+/SFP28/SFP56
sfp-connector- type: LC
sfp-encoding: 64B/66B
sfp-link-length-om1: 30m
sfp-link-length-om2: 80m
sfp-link-length-om3: 300m
sfp-vendor-name: Intel Corp
sfp-vendor-part-number: FTLX8571D3BCV-IT
sfp-vendor-revision: A
sfp-vendor-serial: IN101Q14436
sfp-manufacturing-date: 26-01-31
sfp-wavelength: 850nm
eeprom-checksum: good
eeprom: 0000: 03 04 07 10 00 00 00 00 00 00 00 06 67 00 00 00 … …g…
0010: 08 03 00 1e 49 6e 74 65 6c 20 43 6f 72 70 20 20 …Inte l Corp
0020: 20 20 20 20 00 00 1b 21 46 54 4c 58 38 35 37 31 …! FTLX8571
0030: 44 33 42 43 56 2d 49 54 41 20 20 20 03 52 00 85 D3BCV-IT A .R..
0040: 00 1a 00 00 49 4e 31 30 31 51 31 34 34 33 36 20 …IN10 1Q14436
0050: 20 20 20 20 32 36 30 31 33 31 20 20 00 f0 03 96