What is the key advantage of using switches?

Switches used to reduces the collision.

If a switch needs to forward multiple frames out the same port, the switch buffers the frames in memory, sending one at a time, thereby avoiding collisions. To designate specific end locations prevents Ethernet collisions from accurring. 

the main advantages of using switch is to extend network as well as reducing broadcast domain. the switches are used to connect end devices.

Multiple colision domains

Multiple broadcast domains

Bandwidth improvement per port

More organized communications not having to be used CSMA/CD

Performance

Switch and routed ports

Cost per port

In case, having L3 functions and intelligente services: QoS, Security, VoIP integration, etc.

1) Reduces the number of Broadcast domains2) Supports VLAN's which can help in Logical segmentation of ports[physical ports].Splitting up the broadcast domain.3) Intellegent device[compared to Hub's] which can make use of CAM table for Port to MAC mapping4) Compared to Bridges ,Switches are more H/w oriented therefore operations are less CPU intense[Basic operations].5) The cost to number of ports ratio is best .. ie For a cheaper cost you get switches with more number of ports available than Routers.

1. Switch is more secure, as it makes any port communicate directly with any other port.2. A switch doesn't broadcast requests to all the ports, it keeps its own ARP table and doesn't need to query devices repeatedly.3. Advanced switches can be managed, create VLANs, access lists, etc.4. Advanced switches can be interconnected using a fast bus, where as hubs usually need to be daisy-chained.

--- The cost to number of ports ratio is best .. ie For a 

cheaper cost you get switches with more number of ports

-----minimizing  the number of Broadcast domains

Supports VLAN's which can help in Logical segmentation 

-----more  Intellegent device comparing  to Hub' which can make use 

of CAM table for Port to MAC mapping

logical vsans creation is highly advantage of cisco switches

Will get a more secure and redundancy. Here we have a WWN based zoning called as soft zoning. This zoning is user friendly and we have VSAN here to Isolate the unwanted traffic

The main advantage of using switches is that each switch port has its own collision domain which removes the occurance of collision of frames. It forwards the packets based on the destination address, thereby eleminating unnecessary forwarding of packets to all ports as in hubs.

Switches used to extend network as well as reducing broadcast domain.