Alcatel-Lucent 7950, Quality Of Service Manual

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Queue Group Commands
Page 386 7950 XRS Quality of Service Guide
xp-specific
Syntax xp-specific
Context config>qos>qgrps>egr>qgrp>queue
Description .
packet-byte-offset
Syntax packet-byte-offset { add bytes | subtract bytes }
no packet-byte-offset
Context config>qos>queue-group-templates>egress>queue-group>queue>xp-specific
Description This command is used to modify the size of each packet handled by the queue by adding or subtracting a
number of bytes. The actual packet size is not modified; only the size used to determine the bucket depth
impact is changed.
The packet-byte-offset command is meant to be an arbitrary mechanism that can be used to either add
downstream frame encapsulation or remove portions of packet headers.
When a packet-byte-offset value is applied to a queue instance, it adjusts the immediate packet size. This
means that the queue rates (i.e., operational PIR and CIR) and queue bucket updates use the adjusted packet
size. In addition, the queue statistics will also reflect the adjusted packet size. Scheduler policy rates, which
are data rates, will use the adjusted packet size.
The port scheduler max-rate and the priority level rates and weights, if a Weighted Scheduler Group is
used, are always on-the-wire rates and thus use the actual frame size. The same goes for the agg-rate-limit
on a SAP, a subscriber, or a Multi-Service Site (MSS) when the queue is port-parented.
When the user enables frame-based-accounting in a scheduler policy or queue-frame-based-accounting
with agg-rate-limit in a port scheduler policy, the queue rate will be capped to a user configured on-the-wire
rate, but the packet-byte-offset value is still in effect as explained above.
The no version of this command is used to remove per packet size modifications from the queue.
Parameters add bytes — The add keyword is mutually exclusive to the subtact keyword. Either add or subtract must
be specified. When add is defined, the corresponding bytes parameter specifies the number of bytes that
is added to the size of each packet associated with the queue for scheduling and accounting purposes.
Values 0—32
subtract bytes — The subtract keyword is mutually exclusive to the add keyword. Either add or subtract
must be specified. When subtract is defined, the corresponding bytes parameter specifies the number
of bytes that is subtracted to the size of each packet associated with the queue for scheduling and
accounting purposes. Note that the minimum resulting packet size used by the system is 1 byte.
Values 0—64