MC92501 Datasheet, PDF (35/52 Pages) Motorola, Inc – ATM Cell Processor

SECTION 12. EXTERNAL MEMORY DESCRIPTION
The following table has been added.
12.1. Context Parameters Extension Table
Each context Parameters Extension Table record contains one word, the Common Parameters Extension Word.
12.1.1. Common Parameters Extension Word
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
BKPT[21:12]
0
0
CIFS CEFS ECTE CEME
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
PDV
0
0 EREF 0
ISDM
UOM
0
ICTV ICTE CIME
BKPT[21:12]ÑBucket Pointer[21:12]
When VPAP-VP on all connections, this Þeld contains bits 21 to 12 of the bucket point. When VPAP-VP on all connections is
reset, this Þeld is reserved and should be 0.
CIFSÑConnection Ingress Flow Status
The MC92501 copies the IFSÑOverhead Ingress Flow Status bit to this bit. This bit is used by the ingress processing block
for ABR cell marking. This bit is therefore intended for the MC92501Õs internal use. See Section 5.4.1 for details.
CEFSÑConnection Egress Flow Status
The MC92501 copies the EFSÑOverhead Egress Flow Status bit to this bit. This bit is used by the ingress processing block
for ABR cell marking. This bit is therefore intended for the MC92501Õs internal use. See Section 5.4.2 for details.
ECTEÑEgress CLP Transparency Enable
This bit determines whether CLP should be copied from the EOCLPÑEgress Overhead CLP bit in the cellÕs overhead bit to
the cell header. See Section 6 for details.
0 = CLP should not be copied from the switch overhead to the cell header.
1 = CLP should be copied from the switch overhead to the cell header.
CEMEÑConnection Egress Marking Enable
This bit enables marking of cells which are received in the egress. See Section 5.4.2.
0 = Marking of cells which are received in the egress is disabled.
1 = Marking of cells which are received in the egress is enabled.
IPDVÑIngress Packet Discard Variables
This Þeld is accessed only by the MC92501.
EREFÑEgress Reset EFCI
This bit determines if PTI[1] of an egress cell is to be reset.
0 = PTI[1] of an egress cell is not reset.
1 = PTI[1] of an egress cell is to be reset.
ISDMÑIngress Selective Discard Operation Mode
This Þeld determines the selective discard operation mode. See Section 3.
00 = No selective discard.
01 = Reserved.
10 = Selective discard on CLP = 1 ßow.
11 = Selective discard on CLP = 0+1 ßow.
UOMÑUPC Operation Mode
This Þeld determines the UPC operation mode.
00 = Cell-based UPC
01 = Partial Packet Discard (PPD). See Section 3.3 for details.
10 = Early Packet Discard (EPD). See Section 3.4 for details.
11 = Limited EPD. SeeSection 3.5 for details.
MOTOROLA
MC92501
35