Alcatel-Lucent 6850-48 Network Guide
QoS Policy Overview
Configuring QoS
page 40-4
OmniSwitch AOS Release 6 Network Configuration Guide
September 2009
QoS Policy Overview
A policy (or a policy rule) is made up of a condition and an action. The condition specifies parameters that
the switch will examine in incoming flows, such as destination address or Type of Service (ToS) bits. The
action specifies what the switch will do with a flow that matches the condition; for example, it may queue
the flow with a higher priority, or reset the ToS bits.
the switch will examine in incoming flows, such as destination address or Type of Service (ToS) bits. The
action specifies what the switch will do with a flow that matches the condition; for example, it may queue
the flow with a higher priority, or reset the ToS bits.
Policies may be created directly on the switch through the CLI or WebView. Or policies may be created
on an external LDAP server via the PolicyView application. The switch makes a distinction between poli-
cies created on the switch and policies created on an LDAP server.
on an external LDAP server via the PolicyView application. The switch makes a distinction between poli-
cies created on the switch and policies created on an LDAP server.
Note. Polices may be only be modified using the same source used to create them. Policies configured
through PolicyView may only be edited through PolicyView. Policies created directly on the switch
through the CLI or WebView may only be edited on the switch. Policies may be created through the CLI
or WebView, however, to override policies created in PolicyView. And vice versa.
through PolicyView may only be edited through PolicyView. Policies created directly on the switch
through the CLI or WebView may only be edited on the switch. Policies may be created through the CLI
or WebView, however, to override policies created in PolicyView. And vice versa.
This chapter discusses policy configuration using the CLI. For information about using WebView to
configure the switch, see the OmniSwitch AOS Release 6 Switch Management Guide. For information
about configuring policies through PolicyView, see the PolicyView online help.
configure the switch, see the OmniSwitch AOS Release 6 Switch Management Guide. For information
about configuring policies through PolicyView, see the PolicyView online help.
How Policies Are Used
When a flow comes into the switch, the QoS software in the switch checks to see if there are any policies
with conditions that match the flow.
with conditions that match the flow.
• If there are no policies that match the flow, the flow is accepted or denied based on the global disposi-
tion set for the switch. By default, the disposition is accept. Use the
,
, or
command to change the disposi-
tion. If the flow is accepted, it is placed in a default queue on the output port.
• If there is more than one policy that matches the flow, the policy with the highest precedence is
applied to the flow. For more information about policy precedence, see
• Flows must also match all parameters configured in a policy condition. A policy condition must have
at least one classification parameter.
Once the flow is classified and matched to a policy, the switch enforces the policy by mapping each packet
of the flow to the appropriate queue and scheduling it on the output port. There are a total of eight queues
per port. Traffic is mapped to a queue based on policies, the ToS/802.1p value of the packet, and whether
the port is trusted or untrusted. For more information about queues, see
of the flow to the appropriate queue and scheduling it on the output port. There are a total of eight queues
per port. Traffic is mapped to a queue based on policies, the ToS/802.1p value of the packet, and whether
the port is trusted or untrusted. For more information about queues, see
.