Emerson ATCA-9305 User Manual
System Management:
IPMB Protocol
7-5
IPMB PROTOCOL
The IPMB message protocol is designed to be robust and support many different physical
interfaces. The IPMC supports messages over the IPMB interface. Messages are defined as
either a request or a response, as indicated by the least significant bit in the Network Func-
tion Code of the message.
interfaces. The IPMC supports messages over the IPMB interface. Messages are defined as
either a request or a response, as indicated by the least significant bit in the Network Func-
tion Code of the message.
Table 7-3:
Format for IPMI Request Message
• The first byte contains the responder’s Slave Address, rsSA.
• The second byte contains the Network Function Code, netFn, and the responder’s
Logical Unit Number, rsLUN.
• The third byte contains the two’s-complement checksum for the first two bytes.
• The fourth byte contains the requester’s Slave Address, rqSA.
• The fifth byte contains the requester’s Sequence Number, rqSeq, and requester’s Logical
Unit Number, rqLUN. The Sequence number may be used to associate a specific response
to a specific request.
to a specific request.
• The sixth byte contains the Command Number.
Device-Specific (OEM) Codes 01-7E
01-7E
01-7E
Device specific (OEM) completion codes–command-specific codes (also specific for a
particular device and version). Interpretation of these codes requires prior knowledge of
the device command set.
particular device and version). Interpretation of these codes requires prior knowledge of
the device command set.
Command-Specific Codes 80-BE
80-BE
80-BE
Standard command-specific codes–reserved for command-specific completion codes
(described in this chapter)
(described in this chapter)
Byte:
Bits:
7
7
6
5
4
3
2
1
0
1
rsSA
2
Network Function (netFn)
rsLUN
3
Checksum
4
rqSA
5
rqSeq
rqLUN
6
Command
7:N
Data
N+1
Checksum
Code:
Description:
(continued)