Page 685 - 5G Basics - Core Network Aspects

Transport aspects 2

TSP Time Synchronization Period

TX Transmitter
TXOP Transmission Opportunity

UAS Unavailable Second
UPBO Upstream Power Back Off

US Upstream
UTC Unable To Comply
VBB Vectored Band Blocks

VCE Vectoring Control Entity
VDSL2 Very high speed Digital Subscriber Line transceivers 2

VFC Vectoring Feedback Channel
VFCDR Vectoring Feedback Channel Data Rate
VF Vectoring Feedback

VFRB Vectoring Feedback Report Block
VoIP Voice over Internet Protocol

5 Reference models and system requirements

5.1 System reference models

This Recommendation covers the interface specification between an FTU-O and FTU-R, as applied at the U
reference point. The FTU-O is located inside the distribution point unit (DPU) at the network side of the
wire-pair (U-O reference point). The FTU-R is located inside the network termination (NT) at the customer
premises side of the wire-pair (U-R reference point). Implementations complying with this
Recommendation are typically deployed in a fibre to the-distribution point (FTTdp) scenario.
The functional reference model of FTTdp deployment is illustrated in Figure 5-1.
The upstream traffic from all DPUs is aggregated by the optical distribution network (ODN) and higher
order node (HON) up to the V reference point. The downstream traffic at the V reference point is
distributed towards multiple DPUs by HON and ODN. The aggregation and distribution functions of ODN
and HON are out of the scope of this Recommendation. Different aggregation examples are united under
HON, ODN and DPU, as shown in Figure 5-1.

Each DPU is located at a distribution point and contains one or more FTU-Os, with each FTU-O connected to
a NT. The NT contains an FTU-R, which is a peer of the FTU-O connected to the corresponding DPU.

The management of a DPU is performed by the network management system (NMS), passing management
information to each DPU's management entity (ME) over the Q reference point. The NMS may also monitor
each FTU-R via the related NT's ME via the G reference point. The connection between the ME functions at
the DPU and at the NT is established over management channels provided by the FTU-Os and FTU-Rs via
the wire-pairs.

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