IBM PowerPRS Q-64G
Packet Routing Switch
Preliminary
Figure 3-7. Egress Service Packet Format
High Channel Packet
Byte 0
H0
Byte 1
H1
Byte 2
H2/D
Byte 3
D
Byte 4
D
Byte 5
D
Byte 6
D
Byte 7
D
Byte 8
D
Byte 9
D
Master LU
D
D
D
D
D
D
D
D
D
D
7 Slave LUs
Low Channel Packet
Byte 0
H0
Byte 1
H1
Byte 2 Byte 3
Byte 4
D
Byte 5
D
Byte 6
D
Byte 7
D
Byte 8
D
Byte 9
D
H2/D
D
Master LU
D
D
D
D
D
D
D
D
D
D
7 Slave LUs
Notes:
1. H0, H1, and H2 are packet header bytes. H2 exists only in the 512-Gbps configuration.
2. For command service packets, D is service data. For event service packets, these bytes are ignored by the
attached device and can be filled with any character.
Table 3-22. Egress Service Packet, Byte H0
Information Carried
Byte
Bit 0
Bit 1
Bits 2:3
Bits 4:6
Bit 7
H0
Grant type
Parity
Protection
Service packet type
Reserved
(high channel)
H0
Memory grant
Parity
Protection
Service packet type
Reserved
(low channel)
Table 3-23. Egress Service Packet, Byte H0 Field Descriptions
Bit(s)
Field Name
Description
Identifies the type of grants carried in bytes H1 and H2 of the packet header:
0
1
Subport grants (default value)
Multicast grants (set to ‘1’ every 61 packet cycles or when the multicast grant status
changes)
Grant Type
(high channel)
These bit settings operate the same as those for egress idle packets (see Table 3-11). Bytes H1
and H2 are also formatted the same as they are for egress idle packets (see Tables 3-12 through
3-16).
0
Memory Grant
(low channel)
Reports the status of the memory grant.
1
Parity
Header parity.
2:3
Protection
Must be set to ‘00’ for service packets.
Specifies the type of service packet:
100
101
110
111
Event-1 service packet
Command service packet
Event-2 service packet
Reserved
4:6
7
Service Packet Type
Reserved
Reserved.
Functional Description
Page 46 of 199
prsq-64g.01.fm
December 20, 2001
IBM [ IBM ]
