Page 1052 - 5G Basics - Core Network Aspects

2 Transport aspects

Table Y.2 – DRRdata field sent by FTU

Length
Name Byte Content
(bytes)
5 1 0116 (Note 1)
2 One byte for the reporting block size for queue number
0 (B0)
DRRdata for DRR
3 One byte for the reporting block size for queue number
configuration request
1 (B1)
(FTU-O only)
(Note 2) 4 One byte for the reporting block size for queue number
2 (B2)
5 One byte for the reporting block size for queue number
3 (B3)
DRRdata for DRR 2 1 8116 (Note 1)
configuration confirm
2 Number of QoS queues supported by the NT (NQ)
(FTU-R only)
(Note 2)
NOTE 1 – Byte 1 is used as a message identifier for the DRRdata type. All other values for this byte are reserved by ITU-T.
NOTE 2 – The sizes of the reporting blocks are given in bytes. The reporting block size in the DRR configuration request message
for queues that are not supported by the NT shall bet set to zero

The DRR configuration data sent during the initialization in R-MSG1 shall be identical to the two-byte DRR
configuration confirm data in Table Y.2. The DRA determines the size of the DRRus resources metric (NRM) in
the upstream RMC as one byte per queue with NQ ≤ NRM ≤ 4. The size of the resource metric NRM is
conveyed from the DRA to the FTU-O in the DRRus.request (see Table 8-3) and from the FTU-O to the FTU-R
in the DRR configuration commands (see clause 11.2.2.17).

The means by which a given data packet is mapped to a queue and its associated priority is beyond the
scope of this Recommendation.
NOTE 1 – As an example, Annex I of [b-IEEE 802.1Q-2011] discusses mapping of traffic types to queues (priorities),
where each queue represents a specific QoS behaviour distinct from other queues. In Table I.1 of
[b-IEEE 802.1Q-2011], if there are four queues (i.e., NQ=4), then the traffic types will be mapped to queues (priorities)
as follows:
Queue number Traffic type
0 {Best effort, Background}
1 {Critical applications, Excellent effort}
2 {Voice, Video}
3 {Network control, Internetwork control}
NOTE 2 – As another example, IETF has defined Diffserv forwarding per-hop behaviours (PHBs): best effort (BE) or
default, expedited forwarding (EF), and assured forwarding (AF). If there are three queues (i.e., NQ=3), then these
PHBs will be mapped to queues (priorities) as follows:
Queue number PHB
0 BE
1 AF
2 EF

1042