IBM3229P2035
IBM Packet Routing Switch Serial Interface Converter
Advance
Figure 14: IBM 28.4 Packet Routing Switch (switch) Packet Qualifier Bits Reshuffling
Switch Notation
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Switch
Packet
Priority
Packet
Priority
Packet
Qualifier
Protocol
Engine
Packet
SM
Priority
SM
Priority
Priority of
OQG
Priority of
OQG
Packet
Priority
Packet
Priority
SM Grant
Bit 5
Data / Idle
Bit 2
UTOPIA-3 Notation
Bit 7
Bit 6
Bit 4
Bit 3
Bit 1
Bit 0
Qualifier
• Output Queue Grant Bytes Description
- The IBM Packet Routing Switch Serial Interface Converter egress block provides the OQG values.
There are 16 or 32 bits for each priority.
- For the IBM 28.4 Packet Routing Switch, the first OQG sent is an idle packet’s priority level 00. The
OQG mechanism gives the priority level in the idle packet’s qualifier byte. The other OQGs are sent in
data packets (or idle packets) and the process is looped. In every idle packet sent, the flywheel mech-
anism gives the priority level to check the position in the loop.
- The latest refreshed OQG bits are inserted into the packet header to be sent to the protocol engine.
Table 9: Packet Qualifier for Egress Data Packet
Data Packet
Bit Meaning
Bit 31
0
Bit 30
Bit 29
Bit 28
Bit 27
0
Bit 26
0
Bit 25
Bit 24
Header
Parity
Color/Type Color/Type
Packet Priority Bits
Color/Type
Red Complemented
Red
0
1
1
1
0
1
Blue
Packet Priority
Highest
0
0
1
1
0
1
0
1
Medium High
Medium Low
Lowest
Functional Description
Page 34 of 154
prssi.02.fm
March 1, 2001
IBM [ IBM ]
