Cisco CAB-STACK-1M= Stackwise stacking cables can connect a combination of Catalyst 3750 and 3750-E stackable switches to form a single switching unit
Cisco StackWise is a technology offered by Cisco Systems that will allow for up to nine Catalyst 3750 or 3750-E series switches to operate as though they were one 32-Gbit/s switch. This allows for greater redundancy, and performance.
One switch in the stack will act as the master switch. The master switch will maintain the stack and allow you to configure / monitor the whole stack as though one via a single console.
If one switch fails the remaining switches will continue to operate by looping back any information that would normally traverse the failed switch, effectively bypassing it. If the master switch fails, the next switch in the stack will automatically take over as master. This feature means greater redundancy, as one switch's failure will not bring about a failure of the entire stack.
As each switch contains the entire configuration for the stack one of the benefits of this technology is the ability to replace a down switch (any including master) with a new un-programmed switch. The stack will configure the new switch on the fly and allow for minimal downtime