2) Why are the costs of the SFP modules so different? Here is a generic one: The Cisco ones from FS.com are great, I haven't had to do DWDM but everything I have had from FS.com has been 100% fine.

Like the move from GBIC to SFP the move from ... though Cisco currently only offers lengths up to 5m. This is actually a cable with SFP+ ends, not a module with a separate cable.

When using the WS-G5486 or GLC-LH-SM with 62.5-micron diameter MMF, you must install a mode-conditioning patch cord between the GBIC module or SFP module and the MMF cable on both the transmit and ...

This new revision also includes an SFP112 module specification ... mechanical connector dimensions. SFP-DD MSA promoters include Alibaba Group, Broadcom, Cisco, Dell Technologies, Hewlett Packard ...