I am assuming you have the VIM-2q module installed, so you can connect both switch with a 40Gig link by using QSFP+ transceivers, correct? (As Patrick already wrote, a "show version" would help). Question is: Which optics are you using? Original Extreme Networks optics, or 3rd party? If it's not Extreme, a license is usually needed to operate 3rd party 40G and 100G modules. See here for details on license requirements, as well as more information about pluggable hardware in general: http://documentation.extremenetworks.com/pluggable/PluggableHardware/licensing/licensing_requirementss.shtml PS: I have been connecting those switches successfully, incl. the VIM-2q module, by using Extreme direct attached active optical fiber cables (10 and 20 meter).