Freescale Semiconductor MPC8260 - Manual (Page 949)

ATM Controller and AAL0, AAL1, and AAL5
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 30-29
insert it in an AAL0 TxBD. Finally, issue a ATM TRANSMIT command to send the OAM cell. For multiple
PHYs, use several AAL0 channels—each PHY should have one transmit raw cell queue that is associated
with its scheduling table.
A series of OAM cells can be sent using one ATM TRANSMIT command by creating a table of AAL0
TxBDs. If the channel’s TCT[AVCF] (auto VC off) is set, the transmitter automatically removes it from
the APC (that is, it does not generate periodic transmit requests for this channel after all AAL0 BDs are
processed).
30.6.6 Performance Monitoring
A connection’s performance is monitored by inspecting blocks of cells (delimited by forward monitoring
cells) sent between connection or segment endpoints. Each FMC contains statistics about the immediately
preceding block of cells. When an endpoint receives an FMC, it adds the statistics generated locally across
the same block to produce a backward reporting cell (BRC), which is then returned to the opposite
endpoint.
The PowerQUICC II can run up to 64 bidirectional block tests simultaneously. When a bidirectional test
is run, FMCs are generated for one direction and checked for the opposite.
Figure 30-17 shows the FMC and BRC cell structure.
Figure 30-17. Performance Monitoring Cell Structure (FMCs and BRCs)
Table 30-10 describes performance monitoring cell fields.
Header = 5 bytes Payload = 48 bytes
0010 = Performance Management
OAM
Cell
Type
Function
Type
GFC/ VPI VCI PTI CLP HEC
Function
Specific
Fields
Reserved
VPI
4 4 6 45 x 8 10
CRC-10
Unused
2 octets 4 octets 1 octet 29 octets 2 octets
Time-
Stamp
Total User
Cell 0+1
2 octets
Count
1 octet
0000 = Forward Monitoring (FMC)
0001 = Backward Reporting (BRC)
Monitoring
Sequence
Number Block
Error
Result Total
Received
Cells 0+1
2 octets
Total User
Cell 0
Count
2 octets
Total
Received
Cells 0 Block Error
Detection
Code
(MCSN) (TUC0+1) (BEDC0+1)
1
(TUC0)
(TSTP)
(TRCC0)
2
(BLER)
2
(TRCC0+1)
2
1
BEDC
0+1
appears in FMCs only.
2 TRCC
0
, BLER, and TRCC
0+1
appear in BRCs only.