Ubr+ Protocol-Specific Tcte - Motorola MPC8260 PowerQUICC II User Manual

Part IV. Communications Processor Module
Table 29-25. VBR-Specific TCTE Field Descriptions (Continued)
Offset Bits Name
0x06 0Ð7 SRR Sustain rate remainder. Holds the sustain rate remainder after adding the pace fraction Þeld
to the additive channel sustain rate. Used by the APC to calculate the channel GCRA (leaky
bucket) state. Initialized to 0.
8Ð15 SCRF Holds the sustain cell rate fraction of this channel in units of 1/256 slot.
0x08 Ñ SR Sustain rate. Used by the APC to hold the sustain rate after adding the pace Þeld to the
additive channel sustain rate. Used by the APC to calculate the channel GCRA (leaky
bucket) state.
0x0C 0 VBR2 VBR type
0 Regular VBR. CLP=0+1 cells are rescheduled by PCR or SCR according to the GCRA
1 VBR Type 2. CLP=0 cells are rescheduled by PCR or SCR according to the GCRA state.
1Ð15 Ñ Reserved, should be cleared.
0x0EÐ Ñ Ñ Reserved, should be cleared.
0x1E
29.10.2.3.5 UBR+ Protocol-SpeciÞc TCTE
Figure 29-35 shows the UBR+ protocol-speciÞc TCTE.
0
Offset + 0x00
Offset + 0x02
Offset + 0x04
Offset + 0x06Ð0x1E
Table 29-26 describes UBR+ protocol-speciÞc TCTE Þelds.
Table 29-26. UBR+ Protocol-Specific TCTE Field Descriptions
Offset Bits Name
0x00 Ñ MCR Minimum cell rate for this channel. MCR is in units of APC time slots.
0x02 0Ð7 Ñ Reserved, should be cleared.
8Ð MCRF Minimum cell rate fraction. Holds the minimum cell rate fraction of this channel in units of 1/
15 256 slot.
0x04 Ñ MDA Maximum delay allowed. The maximum time-slot service delay allowed for this priority level
before the APC reduces the scheduling rate from PCR to MCR.
0x06Ð Ñ Ñ Reserved, should be cleared.
0x1E
29-57
state.
CLP=1 cells are rescheduled by PCR.
1 2 3 4
Ñ
Figure 29-35. UBR+ Protocol-Specific TCTE
MPC8260 PowerQUICC II UserÕs Manual
Description
5 6 7 8 9
MCR
Maximum Delay Allowed (MDA)
Ñ
Description
10 11 12 13 14
MCR Fraction (MCRF)
MOTOROLA
15