Re: [Freeipmi-devel] RMCP ping/pongs figured out, maybe a BMC bug??

[Albert Chu]

Hey AB, Bill,

Sorry for this mass of e-mails.  I re-read the specs *again* and I
mis-interpreted.  But I believe there still may be a bug ... In table
12-6 of the IPMI spec ..

"0-FEh, generated by remote console. This is an RMCP version of a
sequence number. Values 0-254 (0-FEh) are used for RMCP request/response
messages. 255 indicates the message is unidirectional and not part of a
request/response pair."

And in the ASF documentation:

"A value of 255 (FFh) indicates that the associated message is not a
request-response type message."

To me, this suggests that the BMC should not accept any ping messages
with a message tag of 255, because RMCP ASF messges are always
request/response messages.

Anyways, I think some errata in Table 12-6 of the IPMI spec would be
nice.  I'm sure I won't be the only one confused by this in the future ...

Thanks ... Everyone have a great Thanksgiving ...

Al

--
Albert Chu
address@hidden
Lawrence Livermore National Laboratory

----- Original Message -----
From: Albert Chu <address@hidden>
Date: Wednesday, November 26, 2003 4:52 pm
Subject: [Freeipmi-devel] RMCP ping/pongs figured out, maybe a BMC bug??

> Hey AB, Bill ...
> 
> I figured the RMCP problem.  It seems the RMCP ASF Message Tag 
> field (
> IPMI spec section 12.2.3) *MUST* be changed between sending 
> consecutiveRMCP ping messages.
> 
> According to the ASF Specification 
> (http://www.dmtf.org/standards/asf):
> "When a duplicate message is received, i.e. one with the same Message
> Tag, the consumer of the message determines whether the message is
> accepted or rejected."
> 
> It seems the tiger 4 BMCs choose to reject the message.  As far as 
> I can
> tell, this isn't specified in the IPMI spec.  It seems quite 
> important.Perhaps it should be added as an errata Bill??
> 
> As for "maybe a BMC bug", the ASF specification also says:
> 
> "A value of 255 (FFh) indicates that the associated message is not a
> request-response type message."
> 
> I interpret this statement to mean that a client should always respond
> to a message with a tag of 255, irregardless if it is a duplicate.  
> WhenI set consecutive RMCP ping messages to have a message tag of 
> 255, later
> packets with a tag of 255 seem to be ignored.  To me, this sounds like
> improper behavior.  Am I interpreting this statement incorrectly??
> 
> Thanks,
> 
> Al
> 
> --
> Albert Chu
> address@hidden
> Lawrence Livermore National Laboratory
> 
> 
> 
> 
> 
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