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Transport aspects 2

Z.4 Generic traffic monitoring functions

Z.4.1 Traffic monitor function (TMF)
The traffic monitor functions (TMF-O and TMF-R) observe the status of the inlet queues at the DPU and the
NT respectively in order to provide queue fill metrics on a per queue basis. The DRA and LRCC-O functions
receive the downstream queue fill metrics from the TMF-O over the  reference point and receive the
upstream queue fill metrics through the DRRUSF from the TMF-R over the R reference point.
The TMF-O sends downstream queue arrival metrics (QADQ), downstream queue fill metrics (QFDQ) and
upstream data stream metrics (QAUA) directly to the LRCC-O and to the DRA. These metrics are provided on
requests from the DRA. The TMF-O shall support requests sourced as low as every 6 ms and shall respond
to such a request in less than 1 ms.

QADQ represents the queue arrival metric for downstream QoS queue Q with a measurement period

starting from the last previous receipt of a QS.request primitive. QADQ values are measured by the TMF-O
on receipt of a QS.request primitive, to form a downstream queue arrival status report (QSR-DS-QA).
QFDQ represents the queue fill metric for downstream QoS queue Q at the time the QS.request primitive is

received. QFDQ values are measured by the TMF-O on receipt of a QS.request primitive, to form a
downstream queue fill status report (QSR-DS-QF).
QAUA represents the data stream metric for STREAMus with a measurement period starting from the last

previous receipt of a QS.request primitive. QAUA values are measured by the USSM function in the TMF-O
on receipt of a QS.request primitive, to form an upstream stream status report (QSR-US-QA).
Upon request from the DRRUSF, the TMF-R sends an upstream queue fill status report (QSR-US-QF at the
NT), which contains the upstream queue fill metrics, to the DRRUSF. The DRRUSF uses this report to create
DRRus (see clause Z.4.2).

The TMF-R shall support requests sourced as low as every logical frame (0.75 ms default value) and shall
respond to such a request in less than 1 ms.

The TMF-O functional reference model is shown in Figure Z.3.

Figure Z.3 – TMF-O and DRA functional models

The TMF-R functional reference model is shown in Figure Z.4.

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