User Manual

M4300 Intelligent Edge Series Fully Managed Stackable Switches
Configuration Examples User Manual702
There are two basic types of QoS:
• Integrated Services: network resources are apportioned based on request and are
reserved (resource reservation) according to network management policy (RSVP
, for
example).
• Differentiated Services: network resources are apportioned based on traf
fic classification
and priority, giving preferential treatment to data with strict timing requirements.
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)
Class
You can classify incoming packets at Layers 2, 3 and 4 by inspecting the following
information for a packet:
• Source/destination MAC address
• EtherT
ype
• 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:
• Dif
fServ traffic classes
• Dif
fServ service levels/forwarding classes
DiffServ Traffic 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