10Gb/s Ethernet: switching to a Broadcom SFP+ module
A home networking enthusiast details his battle against an overheating 10Gb/s Ethernet SFP+ module, identifying and switching to a cooler Broadcom-based transceiver. This deep dive into hardware thermal management and component compatibility resonates with the HN crowd, offering practical solutions to a common, frustrating problem. The discussion explores alternative high-speed networking solutions and the quirks of SFP+ module identity.
The Lowdown
Giles Thomas, having upgraded his home LAN to 10Gb/s, encountered a persistent and frustrating issue: his 10GBASE-T SFP+ module, MikroTik S+RJ10, was running critically hot, causing his network to 'flap' (cycle between operational and shut down). His in-wall CAT-6 cabling necessitated 10GBASE-T, which are known for their heat generation.
- The original Marvell-based SFP+ module in his study switch (
nigel) reached temperatures up to 95C, leading to instability. Temporary fixes like heatsinks and air conditioning proved insufficient or impractical. - Through community insights, he learned that Broadcom-based 10GBASE-T SFP+ modules are generally more power-efficient and run cooler than Marvell equivalents.
- He acquired a
10Gtek ASF-10G-T80-INTmodule, confirmed to use a Broadcom chip, and replaced the problematic MikroTik unit. The installation involved a tricky module removal, but the new one fit and functioned. - Despite the new module reporting itself as an 'Intel' fiber-optic unit and not exposing its temperature via SNMP, a significant improvement was observed: the switch's CPU temperature dropped by approximately 5C.
- More importantly, network stability was restored, with no further instances of flapping even during warmer weather.
The author considers the switch a clear win, highlighting a practical solution to a common thermal challenge in home 10Gb/s copper networking, even if the module's identity reporting was a bit 'mendacious'.
The Gossip
Diverse Data Delivery
Commenters weighed in on various approaches to 10GbE+ networking, often contrasting with the author's 10GBASE-T module choice. Direct Attach Cables (DAC) were frequently recommended for short distances due to their cost-effectiveness and lower heat. Fiber optic connections were also highlighted as a superior, heat-free alternative, though acknowledged to be less convenient when existing copper infrastructure is in place. Discussions also touched on the challenges of 10GbE over copper, with some suggesting it was an inherently problematic standard due to power and heat.
Module Manipulation & Vendor Vexations
The article's mention of modules 'lying' about their identity sparked conversation about SFP+ compatibility and reprogramming. Several users pointed to tools like Unifi's SFP Wizard, the BananaPi BPI-R3, or FS.com's custom-programmed modules and 'FS Box' as solutions for vendor lock-in, compatibility issues, or even upgrading module capabilities (e.g., 10Gb/s DACs to 25Gb/s). This highlighted the common industry practice of modules reporting misleading information and the community's creative workarounds.
Copper's Conundrum: A Retrospective on 10GbE
One prominent comment offered a historical perspective on 10GbE over copper, arguing it was an engineering 'mistake' due to inherent challenges like high cost, stringent cable requirements, and significant heat generation. This perspective contrasted 10GbE's difficulties with the smoother progression of earlier Ethernet standards and the eventual introduction of intermediate speeds like 2.5GbE and 5GbE, suggesting that fiber and modern high-bandwidth technologies like Thunderbolt ultimately superseded copper's viability at these speeds.
Passive Optical Pitfalls
A specific sub-discussion emerged regarding GPON/XGS-PON SFP/SFP+ ONTs, with users sharing similar experiences of these modules running extremely hot. Commenters sought recommendations for cooler-running modules and lamented the lack of integrated cooling solutions, highlighting that thermal management challenges extend beyond standard Ethernet transceivers into specialized networking hardware.