Subject: [IPFIX] IPFIX-MIB Selection Process changes

From: "Thomas Dietz" <[email-masked]>
Date: Thu, 9 Jul 2009 14:50:28 +0200

Dear all,

we are in the course to really finish the IPFIX MIB now. Gerhard identified
a last issue while aligning the IPFIX MIB with the Configuration Model. The
Configuration Model has the following premises:

1) The Metering Process processes only packets from a single Observation
Domain

2) A Selection Process (SP) can be composed of a sequence of multiple
Selectors building a Composite Selector/Selection Sequence

And allows to do the following selections from a observed packet stream:

3) 
          +- SP1 -+
  Stream -+       +- Cache
          +- SP2 -+

4)
               +- Cache1
  Stream - SP -+
               +- Cache2

Premises 1 and 2 were fulfilled with the current version of the MIB but 3
and for 4 were not. To fulfill premise 3 was easy:

To align terminology and fulfill premise 3 we renamed the ipfixSelectorTable
to ipfixSelectionProcessTable and added another index the
ipfixSelectionProcessIndex. So we get the following structure:

+--ipfixSelectionProcessTable(8)
   |
   +--ipfixSelectionProcessEntry(1)
[ipfixMeteringProcessCacheId,ipfixSelectionProcessIndex,ipfixSelectionProces
sSelectorIndex]
      |
      +-- --- Unsigned32       ipfixSelectionProcessIndex(1)
      +-- --- Unsigned32       ipfixSelectionProcessSelectorIndex(2)
      +-- r-n ObjectIdentifier ipfixSelectionProcessSelectorFunction(3)

This allows us to build more than one Selection Process per Metering Process
Cache.

The remaining issue is premise 4. To fulfill this premise we would need to
introduce another table that allows binding Selection Process and Metering
Process Cache but define the Selection Process without actually binding it
to the Metering Process Cache.

I am not sure which relevance this case has in practice. So if you have a
strong opinion have an opinion on the issue please comment.

On the other hand we may live with a workaround as follows:

          +- SP1 - Cache1
  Stream -+
          +- SP2 - Cache2

Where SP1 and SP2 are defined the same, i.e. pointing to the same Selector
Functions. This implies a little loss of information because this
description does not imply that the outputs of SP1 and SP2 are exactly the
same.

I'll publish a new version of the draft on Monday and would appreciate your
feedback until then.

Best Regards,

Thomas

-- 
Thomas Dietz                 E-mail: [email-masked]
NEC Europe Ltd.              Phone:  +49 6221 4342-128
NEC Laboratories Europe      Fax:    +49 6221 4342-155
Network Research Division
Kurfuersten-Anlage 36
69115 Heidelberg, Germany    http://www.nw.neclab.eu

NEC Europe Limited           Registered in England 2832014
Registered Office: NEC House, 1 Victoria Road, London W3 6BL

---

From: Gerhard Muenz <[email-masked]>
Date: Thu, 09 Jul 2009 15:05:00 +0200

Thank you, Thomas.
I support the proposed changes.

Regards,
Gerhard

-- 
Dipl.-Ing. Gerhard Münz
Chair for Network Architectures and Services (I8)
Department of Informatics
Technische Universität München
Boltzmannstr. 3, 85748 Garching bei München, Germany
Phone:  +49 89 289-18008       Fax: +49 89 289-18033
E-mail: [email-masked]    WWW: http://www.net.in.tum.de/~muenz