10 Gb <-> 1 Gb switch interconnect?

[tlemons]

Hi

If I have, say, a 10 Gb Fujitsu XG2000 with CX4 and XFP connections, and I also have (say) a 3Com 4200G Gigabit Ethernet switch with a '1000Base-X' SFP connection, can I connect the two switches together via these XFP/SFP ports? Will the Fujitsu's 10 Gb XFP connection 'slow down' to 1 Gb?

I see (on the XG2000 spec sheet) that it supports:
802.3ae 10 Gigabit Ethernet fiber
802.3ak 10 Gigabit Ethernet CX4

but I don't see any support listed for the slower Ethernet protocols (802.3z or 802.3ab)

I don't see anything in the literature that supports the notion that a 10 Gb Etherent switch can interoperate with a 1 Gb Ethernet switch, but I have a few people here that believe this should 'just work'.

Thoughts?

Thanks!
tl

 

[cajuntank]

It will not. The 10Gb ports are straight 10Gb and do not autosense to other speeds like the 10/100/1000 ports do.