I know nexus 7000 base on multi stage crossbar fabric design , does this mean multi stage cross bar is a CLOS fabric architecture design, there many small crossbar fabric on i/o module and fabric card, and connect by CLOS structure ,and inside fabric ,packet converted to cell to transfer.
another question , why crossbar fabric on i/o card need to access central arbitration on sup, does central arbitration limit performance of whole chassis?
thank you
Tom