Re: OID value for columnar objects in a table, order of objects

[Frank Strauss <strauss@ibr.cs.tu-bs.de>]

Hi!

chintan> Is it true that the value of the last component for
chintan> the OID values assigned to the set of columnar objects
chintan> for a table start at one, and are consecutively
chintan> numbered? 

Yes, this is common practice and a SHOULD in SMI.

chintan> Also is it mandatory that table, row,
chintan> sequence and columnar objects are followed immediately
chintan> one after another. as per rfc2578 i guess the ordering
chintan> is correct.

The ordering is correct and common practice but not mandatory.  I
don't know any reason or MIB example for an exception from this rule.

chintan> eg. xyzTable OBJECT-TYPE
chintan>              ....
chintan>              ....
chintan>              ::= { mib-2 1}

Correct. Tables can be registered at arbitrary not yet allocated OIDs
within your OID namespace.  Hence, mib-2.1 would not be valid. Note
that the SYNTAX of a table node must be `SEQUENCE OF xxxEntry'. This
is what makes it a table and expresses the relation to the xxxEntry
row (not the ordering!).

chintan>     xyzEntry OBJECT-TYPE
chintan>              ....
chintan>              ....
chintan>              ::= { xyzTable 1}

Correct. The sub-id MUST be 1. The SYNTAX must specifiy the SEQUENCE type,
which should be named xxxEntry und usually immediately follows.

chintan>     XyzEntry ::= SEQUENCE {
chintan>         xyzobj1 Integer32,
chintan>         xyzobj2 Integer32,
chintan>         xyzobj3 Integer32
chintan>     }

Correct.

chintan>     xyzobj1 OBJECT-TYPE
chintan>             ....
chintan>             ....
chintan>             ::= { xyzEntry 1}

chintan>     xyzobj2 OBJECT-TYPE
chintan>             ....
chintan>             ....
chintan>             ::= { xyzEntry 2}

chintan>     xyzobj3 OBJECT-TYPE
chintan>             ....
chintan>             ....
chintan>             ::= { xyzEntry 3}

Correct. Again, it's not a MUST that the columnar object types
immediately follow the three definitions above. The columnar sub-ids
are usually numbered by small integers starting at 1.

 -frank