PXB4340E Datasheet, PDF (34/185 Pages) Infineon Technologies AG – ICs for Communications

3;%  (
)XQFWLRQDO 'HVFULSWLRQ
To further limit the load for the microprocessor the DMA function is provided which transfers
relevant status bits for all connections to the control processor memory in the background (see
FKDSWHU ).
The insertion of AIS cells occurs as in the AIS state (FKDSWHU ), i.e. with periodic insertion
of VP-AIS or VC-AIS cells and VP-RDI cells in backward direction. No additional AIS cells are
inserted if AIS and LOC state are declared simultaneously.
Additionally to the standardized CC an Internal Continuity Check ICC is provided as proprietary
function. It uses CC cells with a specially marked header (see VHFWLRQ ) between incoming
and outgoing port. If no AOPE Continuity Check is active a network element ICC can be
activated in order to check the connectivity across the switching network between AOPE
upstream and AOPE downstream. The functionality of ICC does not differ from the AOPE CC
since a received ICC cell is treated like a CC cell, i.e. the same checkers/generators which
otherwise do CC processing are used for ICC with the following consequences :
• insertion of ICC cells in the upstream direction of the AOPE (originating point) if no valid user
cell has been received for a specified time interval of one second.
• supervision of arrived user cells or ICC cells at downstream direction of the AOPE (terminating
point) within a specific time interval of 3.5 +/- 0.5 seconds.
• Loss of ICC cells in downstream direction of the AOPE will result in AIS/RDI generation as
described in VHFWLRQ . The AIS/RDI generation is adjustable via VPC/VCC.
ICC can be activated by software for each valid VPC/VCC.
ICC cells are distinguished from CC cells by the HK bits (HK=100) in the UTOPIA cell header
(UDF1 field). For ICC segment CC cell format is used. If evaluation of the UDF1 field is not
enabled, ICC is not supported.
For ICC the VP/VC segment configuration flags are not relevant. Therefore 3 ATM layer
configuration cases for upstream cell generation are remaining :
• generation of VP ICC cells at VP intermediate points
• geneartion of VC ICC cells at VC originating end points
• generation of VC ICC cells at VC intermediate points
For downstream evaluation are remaining :
• evaluation of VP ICC cells at VP intermediate points
• evaluation of VC ICC cells at VC terminating end points
• evaluation of VC ICC cells at VC intermediate points
ICC cells never leave a switch while ICC is intended for connection supervision within a switch.
 1HWZRUN &RQQHFWLYLW\ &KHFN /%
 *HQHUDO
The loopback (LB) OAM function is intended for checking the connectivity of a virtual connection
by sending a single LB cell along the connection. The LB cell is extracted at well defined points
of the network and sent back to the source via the backward connection. Note that each ATM
connection has an associated connection in backward direction with the same connection
identifiers.
Data Sheet
2-34
04.2000