Page 1332 - 5G Basics - Core Network Aspects

2 Transport aspects

Figure 9-6  FlexO PHY MAP field
9.2.5 Status (STAT)

An 8-bit (1 byte) field is provided for general purpose status indication.
– Remote PHY Fault
– Reserved

Figure 9-7  FlexO OH STAT field

The STAT field is located in all frames, in overhead byte 2.

9.2.5.1 Remote PHY fault (RPF)
For section monitoring, a single bit remote PHY fault (RPF) indication to convey the signal fail status
detected at the remote FlexO sink function in the upstream direction.

RPF is set to ''1'' to indicate a remote PHY defect indication; otherwise, it is set to ''0''.
The RPF field is located in bit 1 of the STAT field as shown in Figure 9-7.
9.2.5.2 Reserved (RES)

Seven bits of the STAT byte are reserved for future international standardization as shown in Figure 9-7.
These bits are set to "0".

9.2.6 OTUC availability (AVAIL)
An 8-bit (1 byte) OTUC availability field is provided to indicate the number of valid and available OTUC slices
mapped to the FlexO frame. A 100G FlexO frame has a valid count of 0 or 1. This functionality is further
specified in clause 10.1.
The AVAIL field is located in frame 2, in overhead byte 3.

9.2.7 Cyclic redundancy check (CRC)
The CRC-16 (2 bytes) is located in overhead bytes 11 and 12 of each FlexO frame. The CRC protects the
integrity of the OH fields in bytes 2 to 10 and excludes the MFAS, OSMC and FCC fields. The CRC-16 uses the
5
3
6
16
G(x) = x + x + x + x + 1 generator polynomial, and is calculated as follows:
1) The overhead bytes 2 to 10 of the OH frame are taken in network byte order, most significant bit
first, to form a 72-bit pattern representing the coefficients of a polynomial M(x) of degree 71.
16
2) M(x) is multiplied by x and divided (modulo 2) by G(x), producing a remainder R(x) of degree 15
or less.

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