
IBM3206K0424
IBM Processor for Network Resources
Preliminary
Packet Header
Page 92 of 676
pnr25.chapt03.01
August 14, 2000
Packet/AAL5 Field Definitions 
Field Name
Field Description
Note
rtoTest
This is the reassembly timeout processing test-and-set bit. It is used by the IBM3206K0424 but should 
be initialized to 
‘
0
’
.
1
rtoEnable
If set, reassembly processing is enabled for this LC, if the LC is running AAL5.
1
tmpCLP
Used by the IBM3206K0424 to track the current state of the ORed CLP bit for the current AAL5 
packet. This field should be set to 
‘
0
’
 at initialization. After initialization, the IBM3206K0424 maintains 
this field.
1
tmpCongestion
Used by the IBM3206K0424 to track the current state of the ORed congestion bit for the current AAL5 
packet. This field should be set to 
‘
0
’
 at initialization time.
1
headerThresh
Specifies how much data should be received before poping a packet start event. If it is set to 
‘
0
’
, only 
complete packet events will be popped.
1
buffPtr
This field is used by the IBM3206K0424, but should be initialized to zero by software. This field is used 
to track the current packet under reassembly.
1
crcState
This field is used by the IBM3206K0424 to maintain the CRC residue as the current packet is reas-
sembled. It should be initialized to 
‘
0
’
.
routedLcd
When routing cells, this field is used to fill in the LCD field of the packet header. This allows the user to 
dynamically route cells back out the interface using a different LCD. The user should be sure to set the 
free on transmit bit in this field as if it were in a packet header.
1
cutThruThresh
Used to determine how much cut-through data is DMAed.
1
dmaedHeader
This is used by the IBM3206K0424 for cut-through Mode 7 processing. This should be initialized to 
‘
0
’
.
1
numDesc
This is used by theIBM3206K0424 for scatter processing, and should be initialized to 
‘
0
’
.
1
packHeadSel
Specifies which packet header should be used for this connection. See 
RXAAL Packet Header Config-
uration
 on page 352 for more information.
1
oamMask
Specifies how OAM traffic should be filtered. See 
ATM OAM Cell Processing
 on page 322 for more 
information.
useCrcNumHead
When set, specifies that receive CRC will determine how many bytes to use for numHeadBytes. This 
is useful when a connection is carrying IP traffic, and the TCP/IP header lengths can be determined.
1
numHeadBytes
Specifies how many bytes of data should be kept with the packet header when DMAing the final DMA 
list for a completed scatter packet. Must be less than the page size.
1
dropNBytes
Allows 0 - 31 bytes of packet data to be dropped from the beginning of the packet on POS-PHY net-
works.
1
1. Software should set up this field.