4 receive raw cell queue, Receive raw cell queue -19, Atm address recognition flowchart -19 – Motorola MPC8260 User Manual

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MPC8260 PowerQUICC II UserÕs Manual

MOTOROLA

Part IV. Communications Processor Module

29.4.4 Receive Raw Cell Queue

Channel one in the RCT is reserved as a raw cell queue. The user should program channel
one to operate in AAL0 protocol. The receive raw cell queue is used for removing
management cells from the regular cell ßow to the host. When a management cell is sent to
the receive raw cell queue, the CP sets RxBD[OAM]. The ALL0 BD speciÞes the channel
code associated with the current OAM cell.

The following are optionally removed from the regular ßow and sent to the raw cell queue:

Segment F5 OAM (PTI = 0b100). To enable F5 segment Þltering, set RCT[SEGF].

End-to-end F5 OAM (PTI = 0b101). To enable F5 end-to-end Þltering, set
RCT[ENDF].

RM cells (PTI = 0b110). When ABR ßow is enabled the cells are terminated
internally; otherwise, they are sent to the raw cell queue.

Reserved PTI value (PTI = 0b111). Always sent to the raw cell queue.

VCI value: 3, 4, 6, 7Ð15. To enable VCI Þltering set the associated bit in the VCIF
entry in the parameter RAM.

Figure 29-9 shows a ßowchart of the ATM cell ßow.

Figure 29-9. ATM Address Recognition Flowchart

Note that even reserved VCI channels should appear in the CAM or address compression
tables; otherwise, a cell on a reserved channel will be considered misinserted.

PTI=1xx or

VCI=3,4,6,7-15

and filter enable

Yes

Check

address

Match

Yes

Discard

cell

Send cell to VC

queue

Send cell to raw

cell queue