Cisco ASA 5505 - Manual (Page 1149)

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Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter 54 Configuring QoS
Licensing Requirements for QoS
You cannot configure traffic shaping and standard priority queuing for the same interface; only
hierarchical priority queuing is allowed. For example, if you configure standard priority queuing for the
global policy, and then configure traffic shaping for a specific interface, the feature you configured last
is rejected because the global policy overlaps the interface policy.
Typically, if you enable traffic shaping, you do not also enable policing for the same traffic, although the
ASA does not restrict you from configuring this.
DSCP and DiffServ Preservation
• DSCP markings are preserved on all traffic passing through the ASA.
• The ASA does not locally mark/remark any classified traffic, but it honors the Expedited Forwarding
(EF) DSCP bits of every packet to determine if it requires “priority” handling and will direct those
packets to the LLQ.
• DiffServ marking is preserved on packets when they traverse the service provider backbone so that
QoS can be applied in transit (QoS tunnel pre-classification).
Licensing Requirements for QoS
The following table shows the licensing requirements for this feature:
Guidelines and Limitations
This section includes the guidelines and limitations for this feature.
Context Mode Guidelines
Supported in single context mode only. Does not support multiple context mode.
Firewall Mode Guidelines
Supported in routed firewall mode only. Does not support transparent firewall mode.
IPv6 Guidelines
Does not support IPv6.
Model Guidelines
• (Multi-processor models, such as the ASA 5500-X, ASA 5580, ASA 5585-X, and ASASM) Traffic
shaping is not supported.
• (ASA 5580) You cannot create a standard priority queue for a Ten Gigabit Ethernet interface. Note:
For the ASA 5585-X, standard priority queuing is supported on a Ten Gigabit Interface.
Model License Requirement
All models Base License.