PMP> Re: How to hande mgmt of shared devices in prtStorage, etc.

PMP> Re: How to hande mgmt of shared devices in prtStorage, etc.

Matt King emking at lexmark.com
Wed Mar 12 16:01:54 EST 1997


Eugene,


Sorry for taking so long to respond, but have been too busy -- some how
I guess you can understand.


On March 6, Eugene Chen wrote:
> Hi, All :
> 
> I have two questions about the meaning of the prtStorageRefTable and
> prtDeviceRefTable in RFC1759.
> 
> 1. Question for prtStorageRefTable :
> 
> I have the following hypothetical situation in which one disk is shared
> between 2 printers.
> 
> The prtStorageRefTable is described as having an entry for each storage device
> in the
> hrStorage table.
> In my example, I have a hrStorageTable with 4 entries (4 harddisks : A, B, C
> and D), and Disk A and B belongs to printer 1, Disk C belongs to printer 2,
> and Disk D belongs to both printers.
> And suppose printer 1 has a deviceIndex of 3 and printer 2 has a
> deviceIndex of 7.
> 
> hrStorageTable :
> hrStorageIndex
>     1               disk A    (printer1 : deviceIndex=3)
>     2               disk B    (printer1 : deviceIndex=3)
>     3               disk C    (printer2 : deviceIndex=7)
>     4               disk D    (printer1 & 2 : deviceIndex=3 & 7)
> 
> So I will have 5 (?) entries in prtStorageRefTable.
> Then my prtStorageRefTable will be :
> 
> prtStorageRefTable :
> hrStorageIndex  prtStorageRefSeqNumber  prtStorageRefIndex
>     1                1                        3
>     2                1                        3
>     3                1                        7
>     4                1                        3     (?)
>     4                2                        7     (?)


I believe you are correct!


> 
> Is the above implementation correct ? Then it violates the description
> under prtStorageRefEntry :
>         "This table will have an entry for each entry in
>         the host MIB storage table that represents storage associated
>         with a printer managed by this agent."
> Because we have 2 entries under one hrStorageTable entry (disk D).


That is not all that is wrong.  Do all hrStorageTable entries have to
belong
to a printer?  As the HR MIB is for a generic host, it hould have
storage that
no printer has access to (e.g. a stand alone print server).


I believe that the description should be updated to be more
clear/correct.


Possibly:
"This table will have an entry for each printer reference
 to an entry in the host MIB storage table that represents
 storage associated with a printer managed by this agent."


> 
> I looked at the Interop mib walk test results.  Vendor 2 has 2 storage devices
> and they use prtStorageRefIndex.1.1 and prtStorageIndex.2.2.  Vendor 4 has 4
> devices,
> with prtStorageRefIndex.1.1, .2.1, .3.1 and .4.1.  Which of these is more
> correct?
> 


I believe that neither is explicitly wrong, however, vendor 2's
implementation
is somewhat odd as the prtStorageRefSeqNumber is incremented for no real
reason.


> 2. Question for prtDeviceRefTable :
> 
> This case is almost exactly the same as the previous example, the parallel
> port, and the processor are shared between two printers.
> 
> This table will have an entry for each hrDeviceTable entry in the hrDevice
> table,
> for example, I have a hrDeviceTable with 7 entries :
> 
> hrDeviceTable :
> hrDeviceIndex
>     1               disk A    (printer1 : deviceIndex=3)
>     2               disk B    (printer2 : deviceIndex=7)
>     3               printer1
>     4               disk C    (printer2 : deviceIndex=7)
>     5               Processor (printer1 & 2 : deviceIndex=3 & 7)
>     6               parallel port (printer1 & 2 : deviceIndex=3 & 7)
>     7               printer2
> 
> So I will have 9 (?) entries in prtDeviceRefTable.
> Then my prtStorageRefTable will be :
> 
> prtDeviceRefTable :
> hrDeviceIndex  prtDeviceRefSeqNumber  prtDeviceRefIndex
>     1                1                        3
>     2                1                        7
>     3                1                        3 (point to printer1 itself ?)
>     4                1                        7
>     5                1                        3 (?)
>     5                2                        7 (?)
>     6                1                        3 (?)
>     6                2                        7 (?)
>     7                1                        7 (point to printer2 itself ?)


Again, I believe you are correct.


> 
> Is the above implementation correct ? Then it violates the description
> under prtDeviceRefEntry :
> Because we have 2 entries under one hrDeviceTable entry (Processor and
> parallel port).


Again I feel that the discription is bad and should be made more
clear/correct.


Possibly:
"This table will have an entry for each printer reference
 to an entry in the host MIB device table that represents
 a device associated with a printer managed by this agent."


> 
> All responses are appreciated. Thank you.
> 
> Eugene Chen
> 
> 
> 


Eugene: Hope I have been of some help.


PWG: Do we want to potentially make these changes to the MIB?


Matt



-- 
Matt King                                     Opinions are my own and
Staff Engineer                                    are not necessarily
Lexmark International, Inc.                          those of Lexmark
emking at lexmark.com




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