MPC8280 datasheet(991/1386 Pages) FREESCALE

991 / 1386 page

ATM Controller and AAL0, AAL1, and AAL5

MPC8280 PowerQUICC II Family Reference Manual, Rev. 1

Freescale Semiconductor

31-31

Before the BRC is transferred to the transmit raw cell queue, the PM function type should be changed to

backward reporting and additional checking should be done regarding the BLER field. If the sequence

numbers (MCSN) of the last two FMCs are not sequential or the differences between the last two TUCs

and the last two TRCCs are not equal, BLER should be set to all ones (see the ITU I.610 recommendation).

NOTE

TRCCs are free-running counters (modulo 65,536) that count user cells

received. The total received cells of a particular block is the difference

between TRCC values of two consecutive BRC cells. TRCC values are

taken from a VC’s performance monitoring table.

31.6.6.3

PM Block Generation

The transmitter generates the PM block. Each time the transmitted cell count parameter (TCC) in the

performance monitoring table reaches zero, the CP inserts an FMC into the user cell stream. The CP copies

the FMC header, SN-FMC, TUC

0+1, TUC0, BEDC0+1-Tx from the performance monitoring table and

inserts them into the FMC payload. The TSTP value (FMC time stamp field) is taken from the MPC8280

time stamp timer; see Section 14.3.8, “RISC Time-Stamp Control Register (RTSCR).”

The TUCs are free-running counters (modulo 65,536) that count transmitted user cells. The total

transmitted cells of a particular block is the difference between TUC values of two consecutive FMCs. The

BEDC (BIP-16, bit interleaved parity) calculation is done on the payload of all user cells of the current

tested block. The performance monitoring block can range from 1 to 2K cells, as specified in the

BLCKSIZE parameter in the performance monitoring table; see Section 31.10.3, “OAM Performance

Monitoring Tables.”

In Figure 31-18, the performance monitoring block size is 512 cells. For every 512 user cells sent, the ATM

controller automatically inserts an FMC into the regular cell stream as defined in ITU I.610. When an FMC

is received, the ATM controller adds the BRC fields to the cell payload and sends the cell to the raw cell

queue. The user can monitor the BRC cell results and transfer the cell to the transmit raw cell queue.

Figure 31-18. FMC, BRC Insertion

FMC Cell

Data Cell

FMC Cell

Data Cell

FMC Cell

512 User Cells

TUC0

Source Cells

Stream

TSTP

BEDC

TUC0+1

TUC0

TSTP

BEDC

TUC0+1

TUC0

TSTP

BEDC

TUC0+1

BRC Cell

TUC0

Destination BRC’s

Transmit Stream

TUC0+1

TSTP

BLER

TRCC0

TRCC0+1

BRC Cell

TUC0

TUC0+1

TSTP

BLER

TRCC0

TRCC0+1

BRC Cell

TUC0

TUC0+1

TSTP

BLER

TRCC0

TRCC0+1

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