I'm looking at provisioning a Catalyst 4500 with a WS-X4712-SFP+E module to allow for future 10Gb connectivity via 10Gb SFP+ interfaces. These cards are backwards compatible with standard 1Gb SFP interfaces but I'm wondering about the other way around; ie. can you populate these blades with 10Gb SFP+ interfaces when they connect to Catalysts with only 1Gb SFP interfaces at the other end?
The data sheets don't really expalin this. I appreciate that it seems pointless getting 10Gb SFP+ interfaces for the 4500 when it's only 1Gb at the access layer end, but these access switches will be replaced in the near future (~12 months) and if the 10Gb SFP+ interfaces support connections at 1Gb speeds upfront, it would mean I could retain these interfaces when the access switches upgrade to 10Gb connectivity capabilities down the track.
Can anyone clarify if the 10Gb SFP+ interfaces are compatible with 1Gb SFP's or only other 10Gb SFP+ interfaces?
Thanks in advance for your help.