pxb4340e Infineon Technologies Corporation, pxb4340e Datasheet - Page 23

• Manufacturer Part Number: pxb4340e
• Description: Atm Oam Processor Aop
• Manufacturer: Infineon Technologies Corporation

Each cell entering the PXB 4340 AOP via the upstream/downstream receive UTOPIA interface
is identified either as user cell or as OAM cell. The chip recognizes all standardized OAM cells
and has two programmable comparators for possible new OAM cell types. Data stored on a
connection basis in the external RAMs determines if a connection is enabled and which layer
point is configured (see
function is performed.
• For example a VP-AIS cell would be ignored at a VP segment endpoint.
• As an other example a user cell belonging to a VPC for which end-to-end performance
In the respective OAM processing block new status information is calculated, for example alarm
indication bits, BIP-16 checksums, cell counts etc.
Whereas user cells are never modified and are always forwarded, OAM cells can be
• generated and inserted into the cell stream in up- or downstream direction
• extracted from the cell stream and discarded or dropped to the receive cell buffer of the µP
• forwarded with or without modification
• looped back with modification.
For OAM cell generation the PXB 4340 AOP uses the configuration bits of the respective
connection to determine the OAM cell type. Therefore it distinguishes between F4 and F5 flow
and between segment and end-to-end flow.
When detecting OAM cells the PXB 4340 AOP recognizes F4 or F5 OAM cells for end-to-end or
segment. According to the configuration the required actions are performed.
The PXB 4340 AOP has four cell buffers located close to the two UTOPIA interfaces in each
direction (
• UTOPIA upstream receive interface: 32 cells, single queue
• UTOPIA upstream transmit interface: 4 cells, single queue
• UTOPIA downstream receive interface: 4 cells, single queue
• UTOPIA downstream transmit interface: 96 cells, shared buffer with 24 queues.
The 4-cell buffers satisfy the needs of the UTOPIA slave handshake at the upstream transmit
and downstream receive interface.
The 32 cells wide upstream receive buffer stores incoming user cells during the insertion of OAM
cells. OAM cells can be generated or looped from the opposite direction. The PXB 4340 AOP
uses forced insertion for all OAM cells. Forced insertion is disabled beyond a buffer filling level
which is programmable for upstream direction via register OAMTHRU (see
90 and
illustration of the cell handling at the UTPOIA upstream receive interface. When the receive
buffer filling level is lower then the threshold the OAM and user cells are processed with the
shown priority.
Data Sheet
monitoring is enabled is counted and its checksum (BIP-16) is added to the checksum in the
AOP located at the VP endpoint.
, part a). The OAM cells to be inserted are lost in this case. Also see
):
for all possible configurations). Accordingly the respective
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