Alcatel-Lucent 7750 SR OS Service Manual page 786

IES Service Configuration Commands
high-prio-only
Syntax high-prio-only percent
no high-prio-only
Context config>service>ies>if>sap>egress>queue-override>queue
config>service>ies>if>sap>ingress>queue-override>queue
Description
This command can be used to override specific attributes of the specified queue's high-prio-only
parameters. The high-prio-only command configures the percentage of buffer space for the queue,
used exclusively by high priority packets.
The priority of a packet can only be set in the SAP ingress QoS policy and is only applicable on the
ingress queues for a SAP. The high-prio-only parameter is used to override the default value derived
from the network-queue command.
The defined high-prio-only value cannot be greater than the MBS size of the queue. Attempting to
change the MBS to a value smaller than the high priority reserve will generate an error and fail execu-
tion. Attempting to set the high-prio-only value larger than the current MBS size will also result in an
error and fail execution.
The no form of this command restores the default high priority reserved size.
Parameters
percent — The percent parameter is the percentage reserved for high priority traffic on the queue. If a
mbs
Syntax mbs {size-in-kbytes | default}
no mbs
Context config>service>ies>if>sap>egress>queue-override>queue
config>service>ies>if>sap>ingress>queue-override>queue
Description
This command can be used to override specific attributes of the specified queue's MBS parameters.
The MBS is a mechanism to override the default maximum size for the queue.
The sum of the MBS for all queues on an egress access port can oversubscribe the total amount of
buffering available. When congestion occurs and buffers become scarce, access to buffers is con-
trolled by the RED slope a packet is associated with. A queue that has not exceeded its MBS size is
not guaranteed that a buffer will be available when needed or that the packet's RED slope will not
force the discard of the packet. Setting proper CBS parameters and controlling CBS oversubscription
is one major safeguard to queue starvation (when a queue does not receive its fair share of buffers).
Another is properly setting the RED slope parameters for the needs of services on this port or channel.
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reserved buffers are required by the queue (a minimal reserved size can still be applied for
scheduling purposes).
Values
0 — 131072 or default
value of 10KBytes is desired, enter the value 10. A value of 0 specifies that none of the MBS of
the queue will be reserved for high priority traffic. This does not affect RED slope operation for
packets attempting to be queued.
Values
0 — 100 | default
7750 SR OS Services Guide