LAS VEGAS -- Notwithstanding an aggressive first strike by Extreme Networks, switching vendors are largely mum on when and in what configurations they will ship 40G Ethernet products. Extreme announced and demonstrated four-port 40G Ethernet modules for its Summit X650 stackable edge and BlackDiamond modular switches at the Interop conference here this week. Extreme is pricing the modules aggressively: $1,000 per port, which is only $85 more than the average selling price of a 10G Ethernet port, according to Dell'Oro Group. 40G not enough for you? Check out our 100G Ethernet cheat sheet Yet, with the exception of Force10 Networks and Brocade, Extreme's competitors would not commit to timeframes for shipping 40G Ethernet products, and only Brocade indicated it could match Extreme's price points. Industry leader Cisco may have a more delicate issue to deal with than determining 40G Ethernet pricing and availability.With a 230Gbps backplane, the current generation of Cisco's new Nexus 7000 data center switch may not have enough horsepower to support 40G Ethernet interfaces at densities that make the technology feasible -- which is eight to 16 ports per slot, industry players say. It would require an upgrade to the 2-year-old Nexus 7000 switch fabric, according to sources inside and outside of Cisco. "It can support 40G, but not at usable densities with a 230G backplane," said one source with knowledge of the situation. "And there's no live migration of the fabric -- it would be outage-based," he said, referring to downtime required to upgrade the switch. A source within Cisco said the company will ship 40G Ethernet on the Nexus 7000 after the standard is ratified in June, and left open the possibility that it could be this year -- "If we can get the optics vendors to play ball" on 40G densities Cisco desires, the source said.