SFF VS SFP compatibility

[notaciscoguy]

hello all, 

I'm not quite certain where to post this. hopefully this is the correct subforum. I have recently inherited a classroom filled with largely outdated and long deprecated switches and routers. most use Gbic ports but some are new enough to have SFP ports on them. I have a handful of transceivers for them that have plastic casings and are labled both SFF and SFP. is there any real difference between SFF and SFP? the reason I ask is I cant seem to get any of these devices to interface while using the plastic cased transceivers. I have a couple metal cased SFPs that work just fine but these plastic ones are garbage. are these intended for a specific type of device or are these just really cheap transceivers that need chucked in the trash?

[chrihussey]

I may not have this 100% correct, but SFF and SFP are different standards. The SFP standard allows for different optical types (850, 1310, 1550, etc) to be plugged into the same slot and has pretty much standardized on the LC type connector for Gig E and Fibre Channel applications.

The SFF is more of a pre-cursor, varies on the connector types and does not allow for the flexibility that SFPs do. 

It does not appear that the SFFs would be compatible with the Cisco switches, and of course Cisco recommends that you only use Cisco SFPs. But if the SFPs you have work, then run with it.

Below is one of the links I came across in my research:

http://xmultiple.com/xwebsite-forum11.htm

Hope this is helpful

[notaciscoguy]

that was pretty much the same gist I was getting which is why I was curious why I have these things that are labeled as SFPs that conform to SFF standards. 

[chrihussey]

I think it is more of SFPs are a type of SFF, but not all SFFs are SFPs. The Cisco's require SFPs.

Whoever was there before you probably just bought the SFFs and thought they would work.

[notaciscoguy]

more than likely that's exactly what happened. one of the challenges of working with so much EOL equipment is constantly needing to research legacy equipment and troubleshooting what I have laying around.