Re: Help explaining the (apparent) extra index seen in atPhysAddress?

Dave Shield <[email protected]>
Newsgroups gmane.network.net-snmp.user
Message-ID <[email protected]>
2009/4/8 Fulko Hew <[email protected]>:
> RFC1213-MIB::atPhysAddress.2.1.10.23.0.1 = Hex-STRING: 00 13 C3 9A 0E E0
>
> Decoding the response I see 3 (?) elements of indexing:

No - that table has two indexes - atIfIndex and atNetAddress
(See the RFC1213-MIB for the definitions).


> atPhysAddress.2.1.10.23.0.1

'2' is the interface index - atIfIndex
"1.10.23.0.1" is the atNetAddress value


> a) I don't understand why the 'extra' element is in the indexing, and what
>    is in the MIB definition for this index variable that tells me to expect it?

"10.23.0.1" is the IP(v4) address, as you've spotted.
the extra element is actually a consequence of how the "NetworkAddress"
syntax type is defined.   From RFC1155

       NetworkAddress ::=
           CHOICE {
               internet
                   IpAddress
           }

It's actually that CHOICE that introduces the .1 subidentifier.


> b) Are there any other situations where this occurs?

No.
The atTable is the only place where NetworkAddress is used.
Note that this table is a hangover from the original MIB-I, and was
deprecated in MIB-II (RFC1213), being effectively replaced by
ipNetToMediaTable (which doesn't use the NetworkAddress
type, and hence omits this .1 subidentifier).

It's obsolete - don't worry about it.

Dave

------------------------------------------------------------------------------
This SF.net email is sponsored by:
High Quality Requirements in a Collaborative Environment.
Download a free trial of Rational Requirements Composer Now!
http://p.sf.net/sfu/www-ibm-com
_______________________________________________
Net-snmp-users mailing list
[email protected]
Please see the following page to unsubscribe or change other options:
https://lists.sourceforge.net/lists/listinfo/net-snmp-users
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.