[XCON] Proposed small fixes to BFCP

[Gonzalo Camarillo <Gonzalo.Camarillo at ericsson.com>]

Folks,

while implementing our BFCP stack (the 'running code' part of the 
protocol), we have discovered a couple of relatively minor bugs in the 
BFCP spec that need to be fixed. They are probably too big to be fixed 
thru RFC editor notes. My suggestion would be to remove the draft from 
the queue, perform the changes I propose below, and send it back to the 
queue. Opinions?


Section 5.3.9 defines the ChairAction message. That message can contain 
several floors (which belong to the same floor request operation) but 
can only provide a single queue position (within the REQUEST-STATUS 
attribute) for all of them. We need to be able to provide different 
queue positions for different floors (e.g., second for floor 1 and third 
for floor 2). In order to do this, we need to define a new grouped 
attribute called FLOOR-REQUEST-STATUS whose definition would be the 
following:

Attribute header:

     0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |x x x x x x x|M|    Length     |           Floor ID            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Attribute ABNF:

 FLOOR-REQUEST-STATUS =   (FLOOR-REQUEST-STATUS-HEADER)
                          (REQUEST-STATUS)
                          [STATUS-INFO]
                         *[EXTENSION-ATTRIBUTE]

Now, the already existing FLOOR-REQUEST-INFORMATION grouped attribute 
would carry '1*(FLOOR-REQUEST-STATUS)' instead of '1*(FLOOR-ID)'

The same for the already existing ChairAction message.


Additionally, we would define a new grouped attribute called 
OVERALL-REQUEST-STATUS, whose definition would be almost identical to 
the FLOOR-REQUEST-STATUS attribute. The only difference is that this one 
would carry a Floor Request ID instead of a Floor ID. This attribute 
would be used within the FLOOR-REQUEST-INFORMATION attribute, whose ABNF 
would become:

OLD:

   FLOOR-REQUEST-INFORMATION =   (FLOOR-REQUEST-INFORMATION-HEADER)
                                 (REQUEST-STATUS)              <--
                               1*(FLOOR-ID)                    <--
                                 [BENEFICIARY-INFORMATION]
                                 [REQUESTED-BY-INFORMATION]
                                 [PRIORITY]
                                 [PARTICIPANT-PROVIDED-INFO]
                                 [STATUS-INFO]                 <--
                                *[EXTENSION-ATTRIBUTE]

NEW:

   FLOOR-REQUEST-INFORMATION =   (FLOOR-REQUEST-INFORMATION-HEADER)
                                 (OVERALL-REQUEST-STATUS)
                               1*(FLOOR-REQUEST-STATUS)
                                 [BENEFICIARY-INFORMATION]
                                 [REQUESTED-BY-INFORMATION]
                                 [PRIORITY]
                                 [PARTICIPANT-PROVIDED-INFO]
                                *[EXTENSION-ATTRIBUTE]



Then, we would need to add a brief discussion on queues, indicating that 
the queue positions in the OVERALL-REQUEST-STATUS attribute refer to 
positions in a global queue for floor requests and that queue positions 
in the FLOOR-REQUEST-STATUS attribute refer to positions in a queue for 
floor requests for a particular floor. Of course, implementations are 
free to implement (or provide information about) one, both, or none of 
these queue types.

The ChairAction message would become:

OLD:

   ChairAction  =   (COMMON-HEADER)
                  1*(FLOOR-ID)             <--
                    (FLOOR-REQUEST-ID)
                    (REQUEST-STATUS)       <--
                    [STATUS-INFO]
                   *[EXTENSION-ATTRIBUTE]

NEW:

   ChairAction  =   (COMMON-HEADER)
                  1*(FLOOR-REQUEST-STATUS)
                    (FLOOR-REQUEST-ID)
                    [STATUS-INFO]
                   *[EXTENSION-ATTRIBUTE]


A different issue (more easily fixable than the issue above) is that the 
FloorRequest and the FloorQuery messages should carry 1*(FLOOR-ID) 
instead of *(FLOOR-ID).

Cheers,

Gonzalo

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