Description  Claims  Drawing  Cited references 

US2006294211A1   [0008] 
US2007201426A1   [0008] 
US2004215819A1   [0008] 

Virtual Switching System (VSS)   [0009] 
Virtual Port Channel (vPC)   [0009] 
Cisco CRS-1 carrier routing system multishelf system outline   [0009]