You can stack switchest together both physically and logically inside a cisco Chassis. This essentially turns all of the individual switches included into one massive switch.
This is advantageous because you only have to have one single point of administration for the whole device. So you don’t have to go from switch to switch to make changes, just doing in the one place rolls it out everywhere.
Cisco also have a technology calls stackwise. This allowed up to 8 switches to be connected together using stackwise cables. When connected together using their stackwise ports they can act together as one big switch. Essentially it works in the same way as the switches aggregated in a chassis.
When set up correctly stackwise can provide some redundancy, so each switch will be linked to 2 other switches. This means that if one of the switches in the stack fail they don’t all stop working.
Some flavours of stackwise even provide failover power, so if power is lost from one of the switches the other switches can power it through the stackwise cable.
When connected with a stackwise cable the master switch stays up, but the next switch in the chain reboots, and when it works out it isn’t the master it takes the configuration from the master switch, and acts like the master switch.
Looking at the interfaces on the second switch when in that main configuration you can tell which switch the interface is on because it will have a different module number in the interface name.
So a port on the master switch might show its first port as”Fa1/0/1″ and the first port on the second switch would be represented as “FA2/0/1”