PXB4219E Datasheet, PDF (50/290 Pages) Infineon Technologies AG – Interworking Element for 8 E1/T1 Lines

IWE8, V3.4
PXB 4219E, PXB 4220E, PXB 4221E
Operational Description
Idle cell identification (Notes
1 and 2)
Physical OAM cell
identification (Note 2) layer
Reserved for use of the
physical layer (Notes 1, 2
and 3)
Octet 1
0000/0000
0000/0000
PPPP/0000
Octet 2
0000/0000
0000/0000
0000/0000
Octet 3
0000/0000
0000/0000
0000/0000
Octet 4
0000/0001
0000/1001
0000/PPP1
P: Indicates the bit is available for use by the physical layer
Values assigned to these but have no meaning with respect to the fields occupying the corresponding bit
positions at the ATM layer
Notes:
1 In the case of physical layer cells, the bit in the location of the CLP indication is not used for the CLP
mechanism as specified in 3.4.2.3.2/I.150.
2 Cells having header values which are identified as idle, physical layer OAM, and reserved for use by the
physical layer are not passed to the ATM layer from the physical layer.
3 Specific pre-assigned physical layer cell header values are given in Recommendation I.432
Figure 11 Pre-assigned cell header values at the UNI (Table 1/I.361)
In contrast to this the ATM-Forum recommends in the User-network interface
specification that the receiving ATM entity is responsible for extraction and discarding of
unassigned and idle cells.
Use
invalid
unassigned
Octet 1
XXXX/0000
0000/0000
Octet 2
0000/0000
0000/0000
Octet 3
0000/0000
0000/0000
Octet 4
0000/XXX1
0000/XXX0
X: Indicates “don’t care” bits
Figure 12 Pre-defined header field values [11]
The RX Idle/Unassigned Cell Control Register (rxid, see Chapter 7.9) can be used in
order to achieve ITU-T or ATM-Forum compliance.
The 4 MSBs of header octet 1 and the 4 LSBs of header octet 4 of the received cells to
be discarded are programmable in bits “prg_rx_hd”. All other header bits must be 0. On
top the “msk_rx_hd” field of “rxid” allows to mask all or some of these bits. The masked
bits are considered as “don’t care”.
• If ITU-T I.361 compliance is desired, the “prg_rx_hd” field should be set to 0000 0001.
If only idle cells should be deleted, the “msk_rx_hd” should be set to 0000 0000.
If all physical layer cells should be deleted, the “msk_rx_hd” should be set to 1111
1110.
Data Sheet
50
2003-01-20