| Description | A table of the extended package objects for queue
management. The [802.3ah] MPCP defines a report message
of the occupancy of the transmit queues for the feedback
BW request from the ONUs. These queues serve the uplink
transmission of the ONU and data is gathered there until
the ONU is granted for transmission.
The management table of the queues is added here mainly
to control the reporting and to gather some statistics
of their operation. This table is not duplicating
existing management objects of bridging queues,
specified in [802.1d], since the existence of a
dedicated transmit queuing mechanism is implied in the
[802.3ah], and the ONU may be a device that is not a
bridge with embedded bridging queues.
The format of the REPORT message, as specified
in [802.3], is presented below:
+-----------------------------------+
| Destination Address |
+-----------------------------------+
| Source Address |
+-----------------------------------+
| Length/Type |
+-----------------------------------+
| OpCode |
+-----------------------------------+
| TimeStamp |
+-----------------------------------+
| Number of queue Sets |
+-----------------------------------+ /|\
| Report bitmap | |
+-----------------------------------+ |
| Queue 0 report | |
+-----------------------------------+ | repeated for
| Queue 1 report | | every
+-----------------------------------+ | queue_set
| Queue 2 report | |
+-----------------------------------+ |
| Queue 3 report | |
+-----------------------------------+ |
| Queue 4 report | |
+-----------------------------------+ |
| Queue 5 report | |
+-----------------------------------+ |
| Queue 6 report | |
+-----------------------------------+ |
| Queue 7 report | |
+-----------------------------------+ \|/
| Pad/reserved |
+-----------------------------------+
| FCS |
+-----------------------------------+
The 'Queue report' field reports the occupancy of each
uplink transmission queue.
The number of queue sets defines the number of the
reported sets, as would be explained in the description
of the dot3ExtPkgQueueSetsTable table. For each set the
report bitmap defines which queue is present in the
report, meaning that although the MPCP REPORT message
can report up to 8 queues in a REPORT message, the
actual number is flexible. The Queue table has a
variable size that is limited by the
dot3ExtPkgObjectReportMaximumNumQueues object, as an
ONU can have fewer queues to report.
The entries in the table are control and status
indication objects for managing the queues of an EPON
interface that are gathered in an extended package as
an addition to the objects that are based on the
[802.3ah] attributes.
Each object has a row for every virtual link and for
every queue in the report.
The LLID field, as defined in the [802.3ah], is a 2-byte
register (15-bit field and a broadcast bit) limiting the
number of virtual links to 32768. Typically the number
of expected virtual links in a PON is like the number of
ONUs, which is 32-64, plus an additional entry for
broadcast LLID (with a value of 0xffff).
The number of queues is between 0 and 7 and limited by
dot3ExtPkgObjectReportMaximumNumQueues. |