ibm3206k0424 ETC-unknow, ibm3206k0424 Datasheet - Page 82

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

IBM3206K0424
IBM Processor for Network Resources
Preliminary
Raw Routed Early Drop LCD
Raw Routed Early Drop LCD Packed and Miscellaneous Field Layouts
A raw routed early drop LCD receives data in the same way that a raw LCD does. Once received, the cell
buffer is then routed internally to the scheduler and rescheduled for transmission. Normally when a cell is
received, the receive LCD address is written into the packet header and the buffer is surfaced to the user.
When a cell is routed, the routedLcd field is used to fill in the LCD address in the packet header. This allows
cells to be routed out the transmit interface with the same or different VP/VC.
This mode should only be used when the routed cell stream is actually an AAL5 packet stream. In this mode,
a cell being dropped due to resource causes the LCD to go into error mode until the cell that contains the user
indicate (UIND) bit is received. All cells received in error mode are dropped, except the final cell which is for-
warded. This conserves bandwidth while maintaining the AAL5 integrity. The finalPoolId provides a second
poolid for the final cells to use to be sure that these final cells are always forwarded even when resources are
low. The finalPoolId is only used if no buffers are available in the normal pool.
The low order bits in the routedLcd field should be set correctly to free the buffer on transmit. These bits cor-
respond to the flag bits in the packet header.
This is also called forwarded or fast forward mode.
Packet Header
pnr25.chapt03.01
Page 82 of 676
August 14, 2000