RELEASED
PM7351 S/UNI-VORTEX
DATA SHEET
PMC-1980582
ISSUE 5
OCTAL SERIAL LINK MULTIPLEXER
Registers 0x089, 0x0A9, 0x0C9, 0x0E9, 0x109, 0x129, 0x149, 0x169:
Upstream Round Robin Weight
Bit
Type
Function
Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Unused
Unused
Unused
Unused
Unused
Unused
RRW[1]
RRW[0]
X
X
X
X
X
X
0
R/W
R/W
0
These registers differentiate the access to the RDAT[15:0] bandwidth for each
serial link. The number of opportunities queued cells have of being transferred
over RDAT[15:0] is proportional to the programmed weight. Under uncongested
conditions, a higher weight will result in a slightly lower cell delay variation (CDV).
Under congested situations (i.e. the instantaneous offered load exceeds the
RDAT[15:0] bandwidth), the ultimate maximum throughput of a link before cell
loss (at the cell buffers on the line card) is proportional to the weighting.
Note that if several S/UNI-VORTEX devices reside on a RDAT[7:0] bus, the
allocation of bandwidth between the S/UNI-VORTEX devices is dependant on
the polling algorithm employed by the bus master.
RRW[1:0]
The Round Robin Weight (RRW(1:0]) selects one of four possible polling
weights for the associated serial link.
RRW[1:0]
Weight
01
10
11
00
1
2
3
4
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
98
PMC [ PMC-SIERRA, INC ]
