Hi,
The supervisor engine, is the main CPU for the chassis. The Supervisor engine is made up of a number of ASICs which perform different and sometime specific functions. For example, layer switching, spanning tree protocol management, etc. The supervisor normally comes with two uplinks. Uplinks are typically used for connectivity to other switches, but not necessarily restricted to switches. The uplink ports on the supervisor are typically nonblocking. That is, they are gauranteed throughput of whatever type of link they are. That is, a 1 GigabitEthernet uplink is gauranteed 1 Gig with no oversubscription. I suggest you read more on this device, perhaps in the datasheet:
http://www.cisco.com/en/US/products/hw/switches/ps708/products_data_sheets_list.html
I hope this helps.
