Alcatel-Lucent 7750 SR Manual page 1309

The secondary shaper leaky bucket, scheduler priority level leaky bucket and the port maximum rate
updates are not affected by the configured packet-byte-offset. Each of these accounting functions are
frame based and always include the preamble, DLC header, payload and the CRC regardless of the
configured byte offset.
The packet-byte-offset command accepts either add or subtract as valid keywords which define
whether bytes are being added or removed from each packet traversing the queue. Up to 31 bytes may
be added to the packet and up to 32 bytes may be removed from the packet. An example use case for
subtracting bytes from each packet is an IP based accounting function. Given a Dot1Q encapsulation,
the command packet-byte-offset subtract 14 would remove the DLC header and the Dot1Q header
from the size of each packet for accounting functions only. The 14 bytes are not actually removed
from the packet, only the accounting size of the packet is affected.
As inferred above, the variable accounting size offered by the packet-byte-offset command is targeted
at the queue and queue group level. The packet-byte-offset, when set, applies to all queues in the quee
group. The accounting size of the packet is ignored by the secondary shapers, the scheduling priority
level shapers and the scheduler maximum rate. The actual on-the-wire frame size is used for these
functions to allow an accurate representation of the behavior of the subscriberís packets on an
Ethernet aggregation network.
The packet-byte-offset value may be overridden at the queue-group level.
Parameters
add add-bytes — Indicates that the byte value should be added to the packet for queue and queue
subtract sub-bytes — Indicates that the byte value should be subtracted from the packet for queue
7750 SR OS Services Guide
• Discarded Low Priority / Out-of-Profile Octet Counter
• Forwarded In-Profile Octet Counter
• Forwarded Out-of-Profile Octet Counter
• Peak Information Rate (PIR) Leaky Bucket Updates
• Committed Information Rate (CIR) Leaky Bucket Updates
• Queue Group Aggregate Rate Limit Leaky Bucket Updates
group level accounting functions. Either the add or subtract keyword must be specified. The
corresponding byte value must be specified when executing the packet-byte-offset command.
The add keyword is mutually exclusive with the subtract keyword.
Values
0 — 31
and queue group level accounting functions. The subtract keyword is mutually exclusive with
the add keyword. Either the add or subtract keyword must be specified. The corresponding byte
value must be specified when executing the packet-byte-offset command.
Values
1 — 32
Virtual Private Routed Network Services
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