Subject: [AAA-WG]: meaning of PXY in the ABNF (P-bit)

From: [email-masked]
Date: Tue, 20 Apr 2004 12:27:02 +0200

Most Diameter commands contain the PXY-keyword in the ABNF spec, meaning 
"if present, the 'P' bit in the Command Flags is set, indicating that 
the message is proxiable".

But does this mean that the P-bit is required in every occurence of this 
command-code ? What if we take a command that is normally proxiable, but 
doesn't carries the P-bit. I guess that most Diameter implementations 
will try to process it locally (if it succeeds depends on the 
Destination-Realm and/or Destination-Host ofcourse). But if a Diameter 
implementation is particular pedantic, and knows from the ABNF (or the 
XML-definition) that the P-bit should be present, it might send an error 
back with the DIAMETER_INVALID_HDR_BITS result-code.

Which would be correct ? In my opinion, we should be able to clear out 
out the P-bit from a command that is normally proxiable, when we want to 
insist that a request should stay local. Ofcourse, the sender would 
still be responsible for correct Destination-Realm and/or 
Destination-Host values, to be sure that it would be really possible to 
process it locally, otherwise it would get a DIAMETER_UNABLE_TO_DELIVER 
back.

-- 
Jo Hermans

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From: <[email-masked]>
Date: Tue, 27 Apr 2004 13:40:30 +0300

Hi Johan,

> back with the DIAMETER_INVALID_HDR_BITS result-code.

The P-bit should be per message.  So a specific message without the p-bit
set would not be proxiable.  An implementation that was pendatntic about 
requiring the p-bit to be set would be, imo, incorrect.

John