IBM3229P2035
Advance
IBM Packet Routing Switch Serial Interface Converter
The EDI GRANT extraction mechanism is synchronized on the incoming idle packet grant flywheel counter.
When a desynchronization problem is detected between the switch counter and the EDI grant flywheel
counter, an error is reported and the EDI flywheel counter is automatically resynchronized. In order to mini-
mize the latency of the switch Grant mechanism, the Grant vector is extracted before the completion of the
packet reception.
The EDI performs switch memory grant synchronization. Memory Grant information and Destination Grant
Vectors are passed to the in band grant generation block for insertion into the egress packets. The EDI is also
the protocol engine interface wrap point.
EDI functions:
• Detect idle packets received from the switch
• Synchronize on switch Output Queue Grant counter
• Output Queue Grant Extraction (one to four priorities traffic)
• Yellow Packet Received Indication (Maskable error Interruption)
• LU CRC checking (Maskable error interruption)
• Header Parity checking (Maskable error interruption) with optional discard
• Data Packet Received Detection
• Wrap Indication Input line (Grant Indication Bypass)
prssi.02.fm
Functional Description
Page 39 of 154
March 1, 2001
IBM [ IBM ]
