ibm3206k0424 ETC-unknow, ibm3206k0424 Datasheet - Page 77

• Manufacturer Part Number: ibm3206k0424
• Description: Ibm Processor For Network Resources
• Manufacturer: ETC-unknow

Preliminary
ABR Code Variables Definitions
pnr25.chapt03.01
August 14, 2000
dma_desc_addr #
timer_period #
bytes_queued
timer_type #
Field Name
pool_id1&2
iMCR
CRM
iCDF
iRDF
PCR
iRIF
ICR
These fields are used to change the POOL ID when a threshold is crossed.
This field is used to keep track of the number of bytes queued for transmission on this LCD.
These encoded bits determine the time of timer:
00 = Relative non-periodic timer The expiration time will be in one timer period. The timer will not
01 = Relative periodic timer
10 = Absolute non-periodic timer The timer will expire at the time specified by the timestamp field.
11 = Absolute periodic timer
This field specifies the number of timeslots before the timer expires.
The DMA descriptor pointed to by this field will be queued for execution when the timer expires.
Missing RM cell count. CRM limits the number of forward RM cells that may be sent in the absence
of received backward RM cells. CDF is written to the NCRM field whenever a backward RM cell is
detected.
Cutoff Decrease Factor (CDF) controls the decrease in ACR associated with CRM. CDF is zero or a
power of 2 value in the range of 1/64 to 1. iCDF represents the power of 2 that is in the denominator
of CDF. CDF = 1/(2**iCDF) so iCDF = log (base 2) of 1/CDF. Range = 1 to 6. A zero value for CDF
should be represented as 0xFF for iCDF.
This is the reciprocal of the Minimum Cell Rate (MCR). MCR is represented in the ABR Rate format.
iMCR needs to be an integer representing the interval between cells, in units of timeslots per cell.
The following formula illustrates the conversion from MCR to iMCR.
iMCR = 1/(MCR) * 53 * 8 * (TSP/CI*(2**23)). The Timeslot Prescalar (TSP) is defined by the CSKED
Timeslot Prescalar Register. The clock interval (CI) is determined by the CRSET Clock Control Reg-
ister. With the TSP set to one timeslot per cell transmission time, iMCR =1 for a full bandwidth, 2 for
a half bandwidth, etc.
The Peak Cell Rate (PCR) is the cell rate that the source may never exceed. PCR should be in the
ABR Rate format.
Rate Decrease Factor (RDF) controls the decrease in the cell transmission rate. RDF is a power of 2
value in the range of 1/32,768 to 1. iRDF represents the power of 2 that is in the denominator of
RDF. RDF = 1/(2**iRDF) so iRDF = log (base 2) of 1/RDF. Range = 1 to 15.
Rate Increase Factor (RIF) controls the increase in the cell transmission rate. RIF is a power of 2
value in the range of 1/32,768 to 1. iRIF represents the power of 2 that is in the denominator of RIF.
RIF = 1/(2**iRIF) so iRIF = log (base 2) of 1/RIF. Range = 1 to 15.
The Initial Cell Rate is the rate at which a source should send initially and after an idle period. ICR
should be in the ABR Rate format.
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be scheduled again automatically.
The expiration time will be in one timer period. The timer will be
automatically scheduled again.
The timer will not be automatically scheduled again.
The timer will expire at the time specified by the timestamp field.
The timer will be scheduled again, automatically, using the time
specified in the timer_period field.
Field Description
IBM Processor for Network Resources
IBM3206K0424
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