ibm3206k0424 ETC-unknow, ibm3206k0424 Datasheet - Page 75

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

Preliminary
ABR Code Variables Definitions
pnr25.chapt03.01
August 14, 2000
head_packet_pointer
max_burst_value #
tail_packet_pointer
transmit_priority #
max_burst_mult #
max_resolution #
transmit_length
queue_on_xmit
alter_sched #
dma_on_xmit
free_on_xmit
Field Name
These encoding bits alter the scheduling of cells on a Virtual Circuit (VC)
000 = Normal Scheduling
001 = VC on VP
010 = MPEG-2 Scheduling
011 = Packet-based scheduling Packets will be scheduled at the average interval and cells within
100 = ABR scheduling
101 = Fair VC on VP
110 = Reserved
111 = Reserved
This field specifies the priority of transmission on this connection: 0=high, 1=medium, 2=low.
If this bit is set, the lower eight bits of the average interval and peak interval parameters contain a
fractional component. This allows a finer resolution for scheduling. For example, for a peak interval
of 1.5 time units, the value written to the peak_interval field should be hex 0180. If this bit is set, the
initial value of timestamp should contain the current timeslot counter shifted 16 bits to the left.
The values in this field and the next field are used to limit the number of cells that can be transferred
at the peak rate. The max_burst_value will be multiplied by four to the power of the value in this field
to yield the maximum credit time. This time is expressed in cell times and represents the time it
would take to acquire the maximum number of cell credits. This maximum credit time should equal
the maximum number of cells that can be transferred at the peak rate (MBS) times the difference
between the average and intervals. Maximum credit time = MBS * (AI-PI) where MBS = maximum
burst size, AI = average interval, and PI = peak interval. MBS must be at least one to transmit at
peak rate. If MBS is not at least one, the peak interval should be set to the average interval.
The value in this field will be multiplied by four to the power of the value in the max_burst_mult field
to yield the maximum credit time.
This field is used to chain buffers to LCDs.
This field is used to chain buffers to LCDs.
This field contains the length of the currently transmitted packet.
This bit is set if the header of the currently transmitted packet has specified that the packet is to be
freed after transmission.
This bit is set if the header of the currently transmitted packet has specified that the packet is to be
queued after transmission.
This bit is set if the header of the currently transmitted packet has specified that a DMA descriptor is
to be queued after transmission.
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Scheduling is not altered.
This VC is contained on a virtual path and will share the VP band-
width after one packet is sent. The scheduling parameters are con-
tained in the descriptor for the virtual path that is pointed to by the
Virtual Path Descriptor Address field in this LCD.
The cells being sent out on this connection are monitored for a
Peak Cell Rate (PCR). If a PCR is found, the AAL5 packet is termi-
nated at the end of the MPEG-2 frame and the last cell is sched-
uled to go out at the time specified in the PCR.
the packet will be scheduled at the peak interval. This is useful for
sending information where variably-sized packets need to be sent
at regular intervals.
This VC will send Resource Management cells and adjust its trans-
mission rate according to the behaviors specified in the ATM
Forum Traffic Management Specification, Version 4.0.
This VC is contained on a virtual path and will share the VP band-
width after one cell is sent. The scheduling parameters are con-
tained in the descriptor for the virtual path which is pointed to by
the Virtual Path Descriptor Address field in this LCD.
For MPEG-2 scheduling.
Field Description
IBM Processor for Network Resources
IBM3206K0424
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Packet Header