On our product, the SFP cages are hooked up directly to the SerDes pins coming off the switch.
We're trying to understand the consequences of doing this vs. say having an SGMII interface hooked to that cage.
There appear to be both SGMII and SerDes versions of 1000Base-T SFPs. For example, the Black Box LFP417:
http://www.blackbox.com/Store/Detail.aspx/SFP-with-SerDes-Interface-1-25-Gbps-Copper-1000BASE-T-Extended-Diagnostics/LFP417
is a 1000Base-T SFP with a SerDes interface, while the LFP416:
http://www.blackbox.com/Store/Detail.aspx/SFP-with-SGMII-Interface-1-25-Gbps-Copper-10-100-1000BASE-T-Extended-Diagnostics/LFP416
is a 1000Base-T SFP with an SGMII interface.
So the first question...
Q1: Do our customers have to buy the right kind of 1000Base-T SFPs to use with a product wired like this, e.g. SerDes SFPs? Since apparently SGMII SFPs are more common, is that an issue?
Q2: What happens if you insert an SGMII 1000Base-T SFP into a SerDes-wired SFP cage? Will it work? Will it auto-negotiate with another switch? Will it support 100Mbps operation or only 1Gbps?
Q3: What happens if you insert a SerDes 1000Base-T SFP into an SGMII-wired SFP cage? Will it work? Will it auto-negotiate with another switch? Will it support 100Mbps operation or only 1Gbps?
Now, in looking at fiber gigabit Ethernet SFPs I'm not seeing this distinction. The SFPs I find for sale don't say whether they are SGMII or SerDes compatible. So again looking at Black Box, they have only one 10km 1310nm single mode 1000Base-LX SFP for sale.
Q4: If we have a SerDes-wired SFP cage, can you use any fiber 1000Base-LX SFPs you like, or only ones that are SerDes compatible?
Q5: If we have an SGMII-wired SFP cage, can you use any fiber 1000Base-LX SFPs you like, or only ones that are SGMII compatible?
