PXB4340E Datasheet, PDF (26/185 Pages) Infineon Technologies AG – ICs for Communications

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The external RAMs for the storage of connection related OAM data are symmetrical in up- and
downstream direction. Also the addressing is symmetrical as the LCI values for forward and
backward connection are identical. Note that according to the standards each ATM connection
is set-up bi-directional, but not necessarily with the same bit rate in both directions.
Both external RAMs are divided into an F4 and an F5 OAM table. Each connection entry has 4
dwords. With the LCI of the cell first the VC-specific table is addressed. Therein an F4 pointer is
contained pointing to a VP-specific entry. There are two cases, both depicted in the circle of
ILJXUH .
.
Connections:
VPCt
VPCi
VCCa
VCCb
16383
16382
16381
:
LCI (VCCa)

F5 entry
16383
16382
16381
:
LCI (VCCb)



F5 entry
F4 pointer:
LCI2(VPCt)
LCI (VPCi)


F4 pointer:
don’t care ^LCI2=LCI
:
F4 entry
:
:
:
:
:
F4 entry

:

2
1
0
:
:
:
2
1
0
F5 OAM table
F4 OAM table
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1. A VPC intermediate point
In this case the F5 entry is "don’t care", except some common fields. See e.g. VPC_i in
ILJXUH . The VP-specific entry contains the OAM data for the VPC.
2. A terminated VPC decomposed into VCCs
In this case each VCC has an F5 entry with identical F4 pointers pointing all to the same
F4 entry. See e.g. VCC_a and VCC_b of VPC_t in ILJXUH .
Data Sheet
2-26
04.2000