Hi all,
We recently encountered issues using certain copper SFP modules with the GigaBlox SFP board. Our bench setup was PC (192.168.88.7) \u2192 copper \u2192 GigaBlox \u2192 SFP \u2192 infrastructure switch (192.168.88.1). With the copper ports on the board the link worked fine, but when using the SFP cage with some copper transceivers the link would come up yet no traffic passed.
Modules that did not work in our tests: 10Gtek ASF-GE2-T, MikroTik S-RJ01, Finisar FCLF-8521-3, Cisco GLC-SX-MM, and similar copper modules. Disabling Energy Efficient Ethernet (EEE) on the NIC did not help. Testing three different GigaBlox SFP boards produced the same behavior.
Modules that did work:\n- Fiber modules using 1000BASE-X (e.g., MikroTik S-45LC80D) worked correctly. In our setup we had to force the remote switch to 1000BASE-X when using fiber. Fixed-rate 1Gbps copper SFPs designed for 1000BASE-X (not multi-rate) worked, such as Ubiquiti UACC-CM-RJ45-1G, TP-Link TL-SM331T, and Alwong ASF-GE-T1.
Findings: The current GigaBlox SFP design uses a 1000BASE-X host interface on the switch chip. Many 10/100/1000BaseT copper SFPs use SGMII internally and are multi-rate, which makes them incompatible with GigaBlox SFP at the moment. Fiber SFPs and fixed-rate 1Gbps copper SFPs (1000BASE-X) link properly.
Workaround: Use fiber SFPs or the fixed-rate 1Gbps copper modules listed above. For fiber, ensure the far-end switch is forced to 1000BASE-X if needed. We plan to investigate adding a firmware option to switch the GigaBlox SFP host interface between SGMII and 1000BASE-X in future revisions.
Hope this helps anyone running into similar issues. Let me know if further details would be useful.