Packet classification is one of the key elements of a routers to implement traffic control techniques.
As an example, let us consider an IPv6 packet such as the following one :
What are the fields of the packet that you can match if you want to implement Layer-2 classification ?
Destination port
Source port
Ethernet source address
TLS record type
Destination IP address
Next header
Ethernet destination address
Hop Limit
Source IP address
Traffic class
Ethernet type
Internet protocol version
What are the fields of the packet that you can match if you want to implement Layer-3 classification ?
What are the fields of the packet that you can match if you want to implement Layer-4 classification ?
What are the fields of the packet that you can match if you want to implement application-level (or layer 7) classification ?