RE: Minutes from the sming wg interim meeting, June6-8,2002 in W ashington DC

"Harrington, David" <[email protected]> Fri, 6 Sep 2002 06:03:39 -0400
Newsgroups gmane.ietf.sming
Message-ID <6D745637A7E0F94DA070743C55CDA9BA075E97@NHROCMBX1.ets.enterasys.com>
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Hi,

As SNMP is being more widely accepted, other standards bodies are creating
their own mibs, and are not always following all the crappy little rules we
define. I have recently run into mibs from other organizations with 0
sub-ids, so we need to be careful about relying on good OID-assignment
behavior, and make sure the rationale behind any crappy little rules that
would affect this are clearly and prominently documented.

dbh

> -----Original Message-----
> From: Steve Waldbusser [mailto:[email protected]]
> Sent: Tuesday, July 23, 2002 9:01 PM
> To: David T. Perkins
> Cc: [email protected]
> Subject: Re: Minutes from the sming wg interim meeting, 
> June6-8,2002 in
> Washington DC
> 
> 
> 
> David,
> 
>   You're right. I think it really reflects an error in the discussion
> and/or minutes rather than an error in the solution.
> 
>   You'll be able to skip any zeros in the base during your 
> traversal to
> the top-level table node. For example, if fooTable is { 0 1 0 1 0 1 },
> then you'll skip the zeros as you parse down to figure out 
> that it's in
> the fooTable. At that point the next node cannot be zero 
> (fooEntry) nor
> can nodes below that.
> 
> Another way to put it is that the zero 'separator' must be after the
> fooTable node. You shouldn't be looking for the separator until after
> you've found the top-level table.
> 
> But we'd better be sure we outlaw zeros in the hierarchy in 
> SMI-DS just
> as we have in 2578 (I think Andy has already done this).
> 
> 
> Steve
> 
> 
> "David T. Perkins" wrote:
> 
> > HI,
> >
> > Note guys that there is a technical assumption in the following that
> > is not correct. That is that a zero valued sub-identifier cannot
> > occur in the OID for an object type. The only restriction that the
> > SMI has it that the last sub-id cannot have a value of zero. Thus,
> > any sub-id from the root (and even the root) can have a value of
> > zero.  For example, it would be valid to have the following
> > definition for an object type:
> >
> >    foo OBJEC-TYPE
> >        ...
> >        ::= { 0 1 0 1 0 1 }
> >
> > The rules are in RFC 2578, section 7.10 (last paragraph).
> >
> > More comments later...
> >
> > Regards,
> > /david t. perkins
> 
> 

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<P><FONT SIZE=3D2>Hi,</FONT>
</P>

<P><FONT SIZE=3D2>As SNMP is being more widely accepted, other =
standards bodies are creating their own mibs, and are not always =
following all the crappy little rules we define. I have recently run =
into mibs from other organizations with 0 sub-ids, so we need to be =
careful about relying on good OID-assignment behavior, and make sure =
the rationale behind any crappy little rules that would affect this are =
clearly and prominently documented.</FONT></P>

<P><FONT SIZE=3D2>dbh</FONT>
</P>

<P><FONT SIZE=3D2>&gt; -----Original Message-----</FONT>
<BR><FONT SIZE=3D2>&gt; From: Steve Waldbusser [<A =
HREF=3D"mailto:[email protected]">mailto:[email protected]=
om</A>]</FONT>
<BR><FONT SIZE=3D2>&gt; Sent: Tuesday, July 23, 2002 9:01 PM</FONT>
<BR><FONT SIZE=3D2>&gt; To: David T. Perkins</FONT>
<BR><FONT SIZE=3D2>&gt; Cc: [email protected]</FONT>
<BR><FONT SIZE=3D2>&gt; Subject: Re: Minutes from the sming wg interim =
meeting, </FONT>
<BR><FONT SIZE=3D2>&gt; June6-8,2002 in</FONT>
<BR><FONT SIZE=3D2>&gt; Washington DC</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; David,</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt;&nbsp;&nbsp; You're right. I think it really =
reflects an error in the discussion</FONT>
<BR><FONT SIZE=3D2>&gt; and/or minutes rather than an error in the =
solution.</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt;&nbsp;&nbsp; You'll be able to skip any zeros in =
the base during your </FONT>
<BR><FONT SIZE=3D2>&gt; traversal to</FONT>
<BR><FONT SIZE=3D2>&gt; the top-level table node. For example, if =
fooTable is { 0 1 0 1 0 1 },</FONT>
<BR><FONT SIZE=3D2>&gt; then you'll skip the zeros as you parse down to =
figure out </FONT>
<BR><FONT SIZE=3D2>&gt; that it's in</FONT>
<BR><FONT SIZE=3D2>&gt; the fooTable. At that point the next node =
cannot be zero </FONT>
<BR><FONT SIZE=3D2>&gt; (fooEntry) nor</FONT>
<BR><FONT SIZE=3D2>&gt; can nodes below that.</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; Another way to put it is that the zero =
'separator' must be after the</FONT>
<BR><FONT SIZE=3D2>&gt; fooTable node. You shouldn't be looking for the =
separator until after</FONT>
<BR><FONT SIZE=3D2>&gt; you've found the top-level table.</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; But we'd better be sure we outlaw zeros in the =
hierarchy in </FONT>
<BR><FONT SIZE=3D2>&gt; SMI-DS just</FONT>
<BR><FONT SIZE=3D2>&gt; as we have in 2578 (I think Andy has already =
done this).</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; Steve</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; &quot;David T. Perkins&quot; wrote:</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; &gt; HI,</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; Note guys that there is a technical =
assumption in the following that</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; is not correct. That is that a zero valued =
sub-identifier cannot</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; occur in the OID for an object type. The =
only restriction that the</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; SMI has it that the last sub-id cannot =
have a value of zero. Thus,</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; any sub-id from the root (and even the =
root) can have a value of</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; zero.&nbsp; For example, it would be valid =
to have the following</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; definition for an object type:</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;&nbsp;&nbsp;&nbsp; foo OBJEC-TYPE</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
...</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
::=3D { 0 1 0 1 0 1 }</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; The rules are in RFC 2578, section 7.10 =
(last paragraph).</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; More comments later...</FONT>
<BR><FONT SIZE=3D2>&gt; &gt;</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; Regards,</FONT>
<BR><FONT SIZE=3D2>&gt; &gt; /david t. perkins</FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
<BR><FONT SIZE=3D2>&gt; </FONT>
</P>

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