Motorola MPC8260 User Manual

29-57

MOTOROLA

29.10.2.3.5  UBR+ Protocol-SpeciÞc TCTE
Figure 29-35 shows the UBR+ protocol-speciÞc TCTE. 

Table 29-26 describes UBR+ protocol-speciÞc TCTE Þelds. 

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 

state.

1 VBR Type 2. CLP=0 cells are rescheduled by PCR or SCR according to the GCRA state. 

CLP=1 cells are rescheduled by PCR.

1Ð15

Ñ

Reserved, should be cleared. 

0x0EÐ
0x1E

Ñ

Ñ

Reserved, should be cleared. 

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Offset + 0x00

MCR

Offset + 0x02

Ñ

MCR Fraction (MCRF)

Offset + 0x04

Maximum Delay Allowed (MDA)

Offset + 0x06Ð0x1E

Ñ

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
15

MCRF Minimum cell rate fraction. Holds the minimum cell rate fraction of this channel in units of 1/

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
0x1E

Ñ

Ñ

Reserved, should be cleared.