Released
Datasheet
PM73487 QRT
PMC-Sierra, Inc.
PMC-980618
Issue 3
622 Mbps ATM Traffic Management Device
Field (Bits)
Description
TX_ALTERNATE_ENCODE
(18)
1
Enable TX, SCG, SC and SCQ alternate congestion encoding. This set
of values of the TX_xxx_EXP_MAX_QD and
TX_xxx_EXP_CONG_QD defines many of the codepoints with higher
values. This increases the resolution of the congestion limits where they
are used most of the time. The coding is:
1111- 31K+1 (31745)
1110 - 24K+1
1101 - 16K+1
1100 - 12K+1
1011 - 8K+1
1010 - 6K+1
1001 - 4K+1
1000 - 3K+1
0111 - 2K+1
0110 - 1.5K+1
0101 - 1K+1
0100 - 769
0011 - 513
0010 - 257
0001 - 9
0000 - 0
0
Disable the TX, SC, SCG, and SCQ alternate encoding. This setting uses
the original set of values which are approximately 2**N.
The coding is:
1111- 31K+1 (31745)
1110 - 16K+1
1101 - 8K+1
1100 - 4K+1
1011 - 2K+1
1010 - 1K+1
1001 - 513
1000 - 257
0111 - 129
0110 - 65
0101 - 33
0100 - 15
0011 - 9
0010 - 5
0001 - 3
0000 - 0
TX_CH_HYSTERESIS_DISABLE
(17)
1
0
Disable TX_CH congestion hyteresis. This setting declares that conges-
tion is relieved when the queue depth drops below the queue depth
defined by the appropriate TX_xxx_EXP_CONG_QD. This setting
might achieve higher throughput in cases where the incoming traffic
characteristics are less bursty.
Enable TX_CH congestion hysteresis. This setting declares that conges-
tion is relieved when the queue depth drops below the queue depth
defined by the appropriate the codepoint one below that defined in
TX_xxx_EXP_CONG_QD. This is a more robust setting which forces
the switch to make the most of each dropping event at the expense of
access to cell buffers in the steady state.
129
PMC [ PMC-SIERRA, INC ]
