
IBM3209K3114
IBM Packet Routing Switch Serial Interface Converter
Advance
Functional Description
Page 28 of 142
prssi.01
July 12, 2000
3.6.4.1 Packets Format
Idle Packets
Idle packets received from EDI have the following format:
16x16 Switch Interface
For idle packets PQ is mapped as follows:
Parity Bit is EVEN parity over 3 bytes PQ, OQG1 and OQG2
32x32 SWITCH Interface
In the packet qualifier the parity bit is EVEN parity over 5 bytes PQ, OQG1, OQG2, OQG3 and OQG4
Note:
The content of PQ byte for yellow packets received from the switch is
’
01001000
’
. It does not contain
flywheel synchronization information because it is generated by the switch control. In the switch, egress yel-
low packets are considered data packets and therefore do not contain link CRC information fields. Yellow
packets are detected and an interruption is reported when the detection function is enabled. When detection
is disabled, the yellow packet is considered a normal time fill packet (idle packet).
Idle Packet CRC Computing
Idle packet CRC detects physical media errors, so the 4x LUs must be covered. The last byte of each LU for
each idle packet carries a CRC byte protecting each LU. The four LU CRC bytes are cumulative between two
idle packets.
The CRC polynom is X8+X4+X3+X2+1. The CRC register is initialized (configuration table address 08 @ 28,
bits 24-31) depending on the LU depth.
Container
Master LU
Slave LU
Slave LU
Slave LU
C00
PQ
x
’
CC
’
x
’
CC
’
x
’
CC
’
C01
OQG1 OQG2
x
’
00
’
x
’
00
’
x
’
00
’
C02
C03
x
’
00
’
x
’
00
’
x
’
00
’
x
’
00
’
C04
x
’
00
’
x
’
00
’
x
’
00
’
x
’
00
’
C05
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
C06
C07
C08
C09
C10
C11
x
’
00
’
x
’
00
’
x
’
00
’
x
’
00
’
C12
x
’
00
’
x
’
00
’
x
’
00
’
x
’
00
’
C13
x
’
00
’
x
’
00
’
x
’
00
’
x
’
00
’
C14
x
’
00
’
x
’
00
’
x
’
00
’
x
’
00
’
C15
CRC
CRC
CRC
CRC
x
’
00
’
x
’
00
’
x
’
00
’
Bit_ 0
Bit_1
Bit_2
Bit_3
Bit_4
Bit_5
Bit_6
Bit_7
0
Header Parity
PQ OQG1
OQG2
0
0
00 (Blue Colored Packet)
01 (Red Colored Packet)
00
01
10
11
Flywheel Counter Synchronization
Highest Priority
Lowest Priority
Master LU
Slave LU
Slave LU
Slave LU
PQ
x
’
CC
’
x
’
CC
’
x
’
CC
’
OQG1 OQG2 OQG3 0QG4 x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
x
’
CC
’
CRC
CRC
CRC
CRC