Motorola MPC8260 - Manual (Page 809)

29-29 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part IV. Communications Processor Module
29.6.5 Transmitting OAM F4 or F5 Cells
OAM F4/F5 ßow cells are sent using the usual AAL0 transmit ßow. For OAM F4/F5 cell
transmission, program channel one in the TCT to operate in AAL0 mode. Enable the CR10
(CRC-10 insertion) mode as described in Section 29.10.2.3.3, ÒAAL0 Protocol-SpeciÞc
TCT.Ó Prepare the OAM F4/F5 ßow cell and insert it in an AAL0 TxBD. Finally, issue a
ATM TRANSMIT command to send the OAM cell. For multiple PHYs, use several AAL0
channelsÑeach 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 channelÕs 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).
29.6.6 Performance Monitoring
A connectionÕs 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 MPC8260 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 29-17 shows the FMC and BRC cell structure.
Figure 29-17. Performance Monitoring Cell Structure (FMCs and BRCs)
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
0001 = Backward Reporting
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) (TUC
0+1
) (BEDC
0+1
) 1 (TUC
0
)
(TSTP)
(TRCC
0
) 2 (BLER) 2 (TRCC
0+1
) 2
1. BEDC
0+1
appears in FMCs only.
2. TRCC
0
, BLER, and TRCC
0+1
appear in BRCs only.