Layer L2/L3/L4 switch 的定義

Layer L2/L3/L4 switch 的定義：

The "Layer" Based on OSI Layer:

A Layer 3 switch performs the function of layer 2 switch which learns,
filters and forwards based on the MAC address, operate on every single
port. But layer 3 includes the ability to examine the IP address.

A Layer 4 switch has the ability to not only examine the IP address but also
to control the traffic based on the port numbers located at Layer 4 of the
OSI model. It is almost similar to a router but with a much higher speed of
data throughput using hardware (ASICs). Layer 4 switch is more intelligent
as it can give priority to data intended for mission critical appl such as
HTTP (port 80) appl on a web server at the same time running less critical
appl on the same server. All these is made possible because it can see both
the port number and IP address of a data packet.