ibm3206k0424 ETC-unknow, ibm3206k0424 Datasheet - Page 322

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

IBM3206K0424
IBM Processor for Network Resources
Miscellaneous Reassembly Functions
ATM OAM Cell Processing
When processing an ATM data stream, OAM cell processing may be necessary. This function needs to be
enabled in the REASM Reassembly Modes Register. REASM performs OAM discrimination when enabled.
This function can be enabled on a per port basis. As cells arrive for processing, the nano-code works together
with some dedicated logic to discriminate between different types of OAM cell traffic. Each type that is
discriminated produces a different event when traffic is surfaced to a receive queue. The different types that
are discriminated are:
Segment
End to End
Segment
End To End
Forward Cell
Backward Cell
Reserved Cell
End to End Alarm
Segment Alarm
End to End Loopback
Segment Loopback
End to End Pm Cell
Segment Pm Cell
End to End
Activate/Deactivate Cell
Segment Activate/
Deactivate Cell
Both the RXCRC and RXAAL nano-code understand and process OAM traffic differently when enabled. In
the receive LCD there are control bits that allow the user to specify on a per connection basis how the OAM
traffic should be handled. There are two types of flows when processing OAM traffic. A connection can be
either "routed" or "terminated." A terminated connection is any connection that terminates either cells or
packets. AAL5 and packet LCDs that are fast forwarded are considered "terminated" because the packet is
terminated before the packet is fast forwarded. A "routed" connection is a raw LCD that is fast forwarded
including raw mode with early packet discard. When OAM traffic is processed on a "terminated" connection,
the OAM traffic can be terminated or dropped based on the discrimination configuration bits in the receive
LCD. A mask value of ’0’ specifies to terminate the cell, and a mask value of ’1’ specifies to drop the cell.
When OAM traffic is processed on a "routed" connection, the OAM traffic can be fast forwarded or dropped
based on the discrimination configuration bits in the receive LCD. A mask value of ’0’ specifies to fast forward
the cell, and a mask value of ’1’ specifies to drop the cell. This allows the user to filter the OAM traffic based
on the type of OAM traffic on a per connection basis.
The mask bit is determined by using the sub-type mask bit if pertinent. For example, an F5 Segment Pm Cell
will use the "Segment Pm Cell" mask bit. If one of the sub-types does not match, then the basic types are
Cell/Packet Re-assembly (REASM)
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VCI = 0003
VCI=0004
Not F4 and PTI field = "100"
Not F4 and PTI field = "100"
PTI = "110" and DIR=0
PTI = "110" and DIR=1
PTI field = "111"
End to End and OAM type=0001 and func=0000 or 0001
Segment and OAM type=0001 and func=0000 or 0001
End to End and OAM type=0001 and func=1000
Segment and OAM type=0001 and func=1000
End to End and OAM type=0010
Segment and OAM type=0010
End to End and OAM type=1000
Segment and OAM type=1000
pnr25.chapt05.01
August 14, 2000
Preliminary