PXB4340E Datasheet, PDF (39/185 Pages) Infineon Technologies AG – ICs for Communications

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VPCI consistency check is supported by the LB function at the VPC terminating end point. The
loopback function of AOPE (upstream) indicates ’VPCI consistency’ by setting a flag, if an F4
end-to-end LB cell is received and successfully looped back at VPC terminating end point. This
flag is reset by SW. The bit VPCCHK in Dword4 of the external RAM entry is the corresponding
to this flag (see VHFWLRQ  page 105, and VHFWLRQ  page 116).
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To make measurement of connection quality possible, the AOPE provides a number of counters.
The Performance Monitoring (PM) flow allows the use and evaluation of these counters. The
counter values are stored in the internal PM main RAM (see VHFWLRQ  page 121).
The AOPE can process 128 bidirectional PM flows configurable for the upstream or downstream
direction on a connection basis (see VHFWLRQ  page 98). PM flows can be applied to the F4/
F5 layer as a segment flow or end-to-end flow.
In the PM flow, forward error detection information (e.g. the error detection code) is
communicated by the PM end points using Forward Monitoring (FM) cells. The performance
monitoring results are received on the reverse direction using Backward Reporting (BR) cells.
After a block of user cells has been received, the related FM cell can be inserted directly within
the next cell cycle. The blocksize is defined in VHFWLRQ  page 122. The first FM cell sent
from the PM originating point is used to initialize the PM terminating point. After an FM cell has
been received at a PM terminating point, the corresponding BR cell is generated (if enabled) and
sent back via the opposite direction, i.e. if it is received upstream it is sent downstream and if it
is received downstream it is sent upstream.
Data Sheet
2-39
04.2000