[cifs-protocol] [REG: 110121779812865] Requesting clarification of CIFS client timeout behavior

Christopher R. Hertel crh at samba.org
Fri Dec 17 16:07:03 MST 2010


Edgar Olougouna wrote:
> Chris,
> 
> This initialization is a protocol behavior which applies to all Windows versions from Windows 2000 and onward. The Client.SessionTimeoutValue default value is defined in the MS-SMB protocol's main body per the guidelines suggested by the Technical Committee.

The timer is a protocol behavior and it must be initialized.  The value that
is used to initialize the timer is a Windows Behavior.  That is already
established in [MS-CIFS], which has a different initial value (45 seconds).

> I have created a new case 110121779812865 and filed a technical document issue on MS-CIFS and passed on your comments to the product group (PG). The PG will assess whether the [MS-CIFS] Client.SessionTimeoutValue default value definition could be in the protocol main body or should remain in the windows behavior note.
> As noted above, this could move to the main body if all Windows-based CIFS SKUs have 45 seconds default value for the Client.SessionTimeoutValue.

Windows systems prior to W2K used 45 seconds.  We know that.  W2K and above
use 60 seconds.

Since the value changed with the version of Windows, the initialization
value is clearly a behavior specific not only to Windows but also to the
version of Windows in use.

> Please let me know whether you have further questions on this topic, otherwise I will consider this issue as resolved.

I just disagree with you.  ...and the two docs now disagree with one another.

Chris -)-----

> Thanks again for your feedback! 
> Edgar
> 
> -----Original Message-----
> From: Christopher R. Hertel [mailto:crh at samba.org] 
> Sent: Thursday, December 16, 2010 5:51 PM
> To: Edgar Olougouna
> Cc: Jeff Layton; pfif at tridgell.net; cifs-protocol at samba.org; MSSolve Case Email
> Subject: Re: [cifs-protocol] [REG: 110121055487273] Requesting clarification of CIFS client timeout behavior
> 
> That makes sense to me.  My only concern is that the value of 45 seconds is given in [MS-CIFS] as a Windows Behavior Note, and not as part of the protocol.  By including the value in the main part of the document, as shown below, and by using the keyword SHOULD, the value of 60 seconds becomes a protocol recommendation rather than a Windows Behavior.
> 
> Chris -)-----
> 
> Edgar Olougouna wrote:
>> Chris, Jeff,
>>
>> In MS-SMB, the Client.SessionTimeoutValue default value should be initialized as follows. 
>>
>> 3.2.3   Initialization
>> Initialization of the following additional parameters is required beyond that specified in [MS-CIFS].
>> The following values MUST be initialized at system startup:
>> ...
>> Client.SessionTimeoutValue is as defined in [MS-CIFS] section 3.2.1.1, and SHOULD be set to 60 seconds.
>>
>> All other values are initialized as specified in [MS-CIFS] section 3.2.3.
>>
>> Thanks,
>> Edgar
>>
>> -----Original Message-----
>> From: Edgar Olougouna
>> Sent: Friday, December 10, 2010 10:15 AM
>> To: 'Christopher R. Hertel'; Jeff Layton
>> Cc: pfif at tridgell.net; cifs-protocol at samba.org; MSSolve Case Email
>> Subject: RE: [cifs-protocol] [REG: 110121055487273] Requesting 
>> clarification of CIFS client timeout behavior
>>
>> Chris, Jeff,
>>
>> For the record, I have created a new case 110121055487273 and filed a technical document issue on MS-SMB. The product team is looking into the best way to reflect the Client.SessionTimeoutValue behavior in MS-SMB, if needed.
>>
>> Thanks for your feedback,
>> Edgar
>>
>> -----Original Message-----
>> From: Christopher R. Hertel [mailto:crh at samba.org]
>> Sent: Thursday, December 09, 2010 5:39 PM
>> To: Jeff Layton
>> Cc: Edgar Olougouna; pfif at tridgell.net; cifs-protocol at samba.org; 
>> MSSolve Case Email
>> Subject: Re: [cifs-protocol] [REG: 110120160951867] Requesting 
>> clarification of CIFS client timeout behavior
>>
>> Jeff Layton wrote:
>> :
>>> Sounds like a reasonable correction. I will note however that I 
>>> didn't actually test Win98 or NT. It's rather difficult to find 
>>> working media for them nowadays since they're not available on MSDN (hint, hint).
>>>
>>> This capture was done with a win2k8 client. I'll have to take your 
>>> word for it that they behave in the same way.
>> It is easy, in the docs, to document actual protocol changes between 
>> NT and
>> W2K+ systems.  Changes to the protocol can and should be documented in [MS-SMB].
>>
>> Unfortunately, it is not nearly as easy to document changes to non-protocol Windows Behavior.  All WBNs really need a to be referenced from within the specification.
>>
>> You can't, for instance, talk about the change from 45 to 60 seconds 
>> between
>> W-NT4 and W2K in [MS-CIFS] because [MS-CIFS] specifically covers 
>> NT3.51 and
>> NT4 clients/servers, and W98 clients.  You also can't talk about it in [MS-SMB] because there is no actual protocol change.
>>
>> The best I could suggest is to add a line somewhere in section 3 of [MS-SMB] that says:
>>
>> Client.SessionTimeoutValue is as defined in [MS-CIFS], section ??? <WBN>.
>>
>> <WBN>: In Windows 2000, Windows 2003, Windows XP, Windows Vista,
>>        Windows 7, Windows 2008, and Windows 2008 R2 (have I missed
>>        any?), the default Client.SessionTimeoutValue is 60 seconds.
>>
>> ...and then reference both the KB article and the section of [MS-CIFS] that provides the WBN that states that the timeout is 45 seconds.
>>
>> Chris -)-----
>>
>> --
>> "Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
>> Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
>> jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
>> ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
>> OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org
>>
> 
> --
> "Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
> Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
> jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
> ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
> OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org
> 

-- 
"Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
Samba Team -- http://www.samba.org/     -)-----   Christopher R. Hertel
jCIFS Team -- http://jcifs.samba.org/   -)-----   ubiqx development, uninq.
ubiqx Team -- http://www.ubiqx.org/     -)-----   crh at ubiqx.mn.org
OnLineBook -- http://ubiqx.org/cifs/    -)-----   crh at ubiqx.org


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