Re: [IPFIX] Initial review of draft-ietf-ipfix-mib-variable-export-03

On Sun, Nov 03, 2013 at 04:14:53PM -0800, Andrew Feren wrote:
> On 11/03/2013 11:05 AM, Juergen Schoenwaelder wrote:
> > On Fri, Nov 01, 2013 at 04:47:05AM +0100, Brian Trammell wrote:
> >> (3) Clarifying and SNMP-naif question on 11.2.2 mibObjectIdentifier: it
> >> seems from the examples that the intention is that the OID will be
> >> encoded in the document as a Unicode string of digits and "."
> >> characters? Is this the way OIDs are encoded in SNMP? The encoding of
> >> fundamentally binary data in strings is not very IPFIXish (7013 section
> >> 4.2 para 6), and I kind of expected these to be encoded as octetarrays
> >> of unsigned integers of a specified size, or something similar. However,
> >> if encoding-as-string is how things are done on the wire in SNMP, it's
> >> the right thing to do here too (7013 section 4.5). The same comment
> >> applies to 11.2.4.
> >>
> > SNMP uses ASN.1/BER and this gives you are much more compact encoding
> > of OIDs (but this is of course a much less human/programmer friendly
> > representation).
> 
> So, would a simple octetArray like Brian asked about make sense?  I'm
> still not sure.

Not sure exactly what Brian proposed but a sub-identifier can be up to
32-bit long.
 
> >> IpAddress -> ipv4Address (side question: how do you do V6 with SNMP?)
> > The IPv6 address types are an OCTET STRING on the wire (not a tagged
> > type anymore).
> 
> I've occasionally wondered if an ipAddress type (varlen 4 or 16 octets)
> would be useful in IPFIX.

Maybe it is but surely this is not how SNMP represents data; the
InetAddress textual convention actually can carry zone indexes and
hence the assumption 4 or 16 octets may not hold true in general.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1, 28759 Bremen, Germany
Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>
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