Page 1003 - 5G Basics - Core Network Aspects

Transport aspects 2

The control parameter L2.2_ETR_min is derived by the DRA from the DPU-MIB minimum expected
throughput in the L2.2 link state (L2.2-MINETR) configuration parameter.

The parameter value is identical for upstream and downstream.
13.4.2.5.2 Maximum Net Data Rate in L2.2 (L2.2_NDR_max)

L2.2_NDR_max is a control parameter that specifies the maximum allowed value for the net data rate at
L2.2 entry and during the L2.2 link state, L2.2_NDR (see clause 13.4.4.2).

It is used in the L2.2 entry policy.
The field shall be formatted as a 16-bit unsigned integer with LSB weight of 16 kbit/s and has a valid range
of values from 4 × L2.2_ETR_min kbit/s to 4 096 kbit/s, further limited to the possible values based on valid
values of framing parameters.

The control parameter L2.2_NDR_max is derived by the DRA from the DPU-MIB maximum net data rate in
the L2.2 link state (L2.2-MAXNDR) configuration parameters.

The parameter value is identical for upstream and downstream.

13.4.3 Transition between L2.1N and L2.1B
The procedure defined in this clause shall be used to transition from L2.1N into L2.1B and from L2.1B into
L2.1N. The transition shall be initiated by the FTU-O. Upon reception of a LinkState.request primitive across
the γ-O interface (see Table 8-3), the FTU-O shall complete or terminate all OLR procedures and send to the
FTU-R an L2.1-Transition-Request eoc command, which indicates the requested transition (see clause
11.2.2.16). Upon reception of an L2.1-Transition-Request eoc command, the FTU-R shall respond within a
time consistent with the timeout value in Table 11-2 by sending an L2.1-Transition-Confirm eoc response
(see clause 11.2.2.16). The FTU-R shall not reject the L2.1-Transition-Request eoc command.

The FTU-O shall not initiate an L2.1 transition procedure before all running OLR procedures have been
completed (i.e., either rejected or accomplished). After sending an L2.1-Transition-Request eoc command,
the FTU-O shall reject all Type 1 and Type 2 OLR requests from the FTU-R, until the reception of an L2.1-
Transition-Confirm eoc response using the corresponding reject OLR request response with reason code
"wait". After reception of an L2.1-Transition-Request, the FTU-R shall not send any Type 1 or Type 2 OLR
requests until it sends an L2.1-Transition-Confirm eoc response.
After reception of an L2.1-Transition-Confirm eoc response, the FTU-O shall confirm to the DRA using the
LinkState.confirm (LinkStateResult) primitive.

The L2.1 parameters and transmission format shall remain unchanged in this transition.
In the case that an L2.1-Transition-Request eoc command times out (see Table 11-2), the FTU-O shall send a
new L2.1-Transition-Request with the same requested transition. The FTU-O shall repeat this until a valid
L2.1-Transition-Confirm eoc response is received from the FTU-R. The FTU-O shall continue repeating the
request, until a fast retrain condition is reached according to the L2.1-FRpolicy = 0 (see clause 12.1.4.2).
Upon reception of an L2.1-Transition-Request with the same requested transition as a previous
L2.1-Transition-Request, the FTU-R shall respond by sending an L2.1-Transition-Confirm eoc response.
NOTE 1 – An FTU-O may send multiple L2.1-Transition-Requests with the same requested transition, for example in
the case when the L2.1-Transition-Confirm was not received due to impulse noise.
NOTE 2 – The L2.1 transmission schedule may be adapted using a subsequent L2TSA procedure, for example, for more
power savings in L2.1B state.

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