Alcatel-Lucent 7950 Quality Of Service Manual page 184

Service Ingress QoS Policy Commands
priority — This parameter overrides the default enqueuing priority for all packets received on an ingress
SAP using this policy that match this rule. Specifying the priority is optional. When a packet matches
the rule the enqueuing priority is only overridden when the priority parameter is defined on the rule. If
the packet matches and priority is not explicitly defined in the rule, the enqueuing priority is inherited
based on previous rule matches.
Default
high — This parameter is used in conjunction with the priority parameter. Setting the enqueuing parameter
to high for a packet increases the likelihood of enqueuing the packet when the ingress queue is
congested. Ingress enqueuing priority only affects ingress SAP queuing. Once the packet is placed in a
buffer on the ingress queue, the significance of the enqueuing priority is lost.
Default
low — This parameter is used in conjunction with the priority parameter. Setting the enqueuing parameter
to low for a packet decreases the likelihood of enqueuing the packet when the ingress queue is
congested. Ingress enqueuing priority only affects ingress SAP queuing, once the packet is placed in a
buffer on the ingress queue, the significance of the enqueuing priority is lost.
Default
dscp
Syntax dscp dscp-name [dscp-name...(upto 8 max)] [fc fc-name] [hsmda-counter-override counter-id]
[profile {in | out}]
no dscp dscp-name [dscp-name...(upto 8 max)]
Context config>qos>sap-egress
Description This command defines IP Differentiated Services Code Point (DSCP) names that must be matched to
perform the associated reclassification actions. The specified name must exist as a dscp-name. SR OS
software provides names for the well-known code points. A list of up to 8 dscp-names can be entered on a
single command. The lists of dscp-names within the configuration are managed by the system to ensure that
each list does not exceed 8 names. Entering more than 8 dscp-names with the same parameters (fc, hsmda-
counter-override, priority) will result in multiple lists being created. Conversely, multiple lists with the same
parameters (fc, hsmda-counter-override, priority) are merged and the lists repacked to a maximum of 8 per
list if dscp-names are removed or the parameters changed so the multiple lists use the same parameters.
Also, if a subset of a list is entered with different parameters then a new list will be created for the subset.
Note that when the list is stored in the configuration, the dscp-names are sorted by their DSCP value in
ascending numerical order, consequently the order in the configuration may not be exactly what the user
entered.
If an egress packet on the SAP matches an IP DSCP value corresponding to a specified dscp-name, the
forwarding class, profile or HSMDA egress queue accounting behavior may be overridden. By default, the
forwarding class and profile of the packet is derived from ingress classification and profiling functions. The
default behavior for HSMDA queue accounting is to use the counters associated with the queue to which the
packet is mapped. Matching a DSCP based reclassification rule will override all IP precedence based
reclassification rule actions.
The IP DSCP bits used to match against dscp reclassification rules come from the Type of Service (ToS)
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low priority
low priority
Inherit (When priority is not defined, the rule preserves the previous enqueuing priority
of the packet.)
7950 XRS Quality of Service Guide