Netgear M4300-24X24F (XSM4348S) - Stackable Managed Switch with 48x10G including 24x10GBASE-T and 24xSFP+ Layer 3 Manual Do Utilizador

The DiffServ feature contains a number of conceptual QoS building blocks you can use to 
construct a differentiated service network. Use these same blocks in different ways to build 
other types of QoS architectures.

There are 3 key QoS building blocks needed to configure DiffServ:

Class

Policy

Service (the assignment of a policy to a directional interface)

You can classify incoming packets at Layers 2, 3 and 4 by inspecting the following 
information for a packet:

Source/destination MAC address

EtherType

Class of Service (802.1p priority) value (first/only VLAN tag)

VLAN ID range (first/only VLAN tag)

Secondary 802.1p priority value (second/inner VLAN tag)

Secondary VLAN ID range (second/inner VLAN tag)

IP Service Type octet (also known as: ToS bits, Precedence value, DSCP value)

Layer 4 protocol (TCP, UDP and so on)

Layer 4 source/destination ports

Source/destination IP address

From a DiffServ point of view, there are two types of classes:

DiffServ traffic classes

DiffServ service levels/forwarding classes

With DiffServ, you define which traffic classes to track on an ingress interface. You can define 
simple BA classifiers (DSCP) and a wide variety of multi-field (MF) classifiers:

Layer 2; Layers 3, 4 (IP only)

Protocol-based

Address-based

You can combine these classifiers with logical AND or OR operations to build complex 
MF-classifiers (by specifying a class type of all or any, respectively). That is, within a single 
class, multiple match criteria are grouped together as an AND expression or a sequential OR 
expression, depending on the defined class type. Only classes of the same type can be 
nested; class nesting does not allow for the negation (exclude option) of the referenced 
class.