ATM AAL1 Circuit Emulation Service
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
31-2 Freescale Semiconductor
Segment PDU directly from external memory
Partially filled cells support (configurable on a per-VC basis)
Sequence number generation
Sequence number protection (CRC-3 and even parity) generation
Pointer generation during segmentation in structure AAL1 cell format
Clock recovery using external SRTS logic during reassembly in unstructured AAL1
Statistics gathering on a per-VC basis:
– AAL1 Tx cell count
– AAL1 Tx buffer underrun
Circuit emulation service (CES)
ATM to TDM
Structured and unstructured data are transferred between the ATM and MCC automatically
without CPU intervention
In case of pre-underrun, the MCC start sending the last frame or the user-defined underrun
template. The MCC and ATM controller automatically perform slip control with no CPU
intervention.
In case of pre-overrun, the ATM receiver discards incoming cells until the MCC transmitter
empties enough buffers for the receiver to restart.
Supports common channel signaling (CCS)
Supports channel associated signaling (CAS)
– Up to 4 (one per trunk) CAS blocks residing in internal RAM when in automatic
CAS mode and up to 8 blocks when in core CAS modify mode
– Supports Nx64 E1/T1 channels
– CAS routing table on per-VC basis
– Automatic un-packing of the CAS information during reassembly and updating
of the internal CAS block
—TDM to ATM
Structured and unstructured data are automatically transferred between the MCC and ATM
controller without CPU intervention
Supports common channel signaling (CCS)
Supports channel associated signaling (CAS)
– Up to 4 (one per trunk) CAS blocks residing in internal RAM when in automatic
CAS mode and up to 8 blocks when in core CAS modify mode
– Support Nx64 E1/T1 channels
– CAS routing table on per-VC basis
– Automatic packing of CAS information from internal RAM to AAL1 Tx cells
– Once per superframe, the CPM fetches the CAS information from an external
framer and updates each internal CAS block.