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PSAMP WG meeting minutes for IETF #57



Hi,

Attached are the meeting minutes for the PSAMP meeting in Vienna.

Andy
OPS Area
PSAMP WG Meeting Minutes
IETF #57
July 17, 2003
Minutes by Andy Bierman

Review Material
---------------

  A) draft-ietf-psamp-framework-03.txt
  B) draft-ietf-psamp-sample-tech-02.txt
  C) draft-ietf-psamp-mib-00.txt

Agenda
------

  1) WG Status
  2) Sampling Framework Issues
  3) Packet Selection Issues
  4) Report Format and Export Protocol
  5) PSAMP MIB

Minutes
-------

1) WG status

The milestones for the working group were presented and briefly
discussed:

Initial   Final
Draft     Draft        Description
----------------------------------------------------------------------
Done      May 03       PSAMP Framework
Done      May 03       Packet Selector and Packet Information
Feb 03    Sep 03       Report Format and Report Stream Format
Mar 03    Oct 03       Export Protocol and Requirements for Collectors
Done      Nov 03       PSAMP MIB

The report format and export protocol documents are behind
schedule because the working group decided to use the
mechanisms developed by the IPFIX WG for these purposes.
The IPFIX WG is not scheduled to complete these documents
until the end of the year.

2) Sampling Framework Issues

The Framework draft (A) was discussed by the group.

2.1) Terminology

Some clarifications are needed in PSAMP terminology:
  - PSAMP device is not a precise enough term
  - need clarification between filtering and sampling.
    Distinction is not always clear (e.g., hashing)

2.2) Conformance

It is not clear where specific conformance requirements
should be specified.  It is likely that requirements
related to a portion of PSAMP covered by another document,
such as packet selection or report export, should be moved
to that document.

Some packet report requirements were discussed, such as
  - packet reports must contain:
      - first N bytes
      - report sequence number
      - administrative details (selector ID)

The congestion avoidance requirement for the export process
was discussed briefly.  There is a desire to meet this
requirement in a way that is not too burdensome on PSAMP
devices.

The requirements for the PSAMP MIB were briefly discussed.
These include some mandatory configuration objects and
some optional (additional) complex configuration objects,
for such features as multiple selectors and filtering.

Security requirements were also discussed.  There is
a need for secure export, which includes:
   - confidentiality
   - integrity
   - authentication of sender
   - secure configuration

2.3) Open Issues

There may be a need to make adjustments to the document
for better alignment with IPFIX terminology.  There are
some minor sections (such as an overview of configuration)
that need to be completed.  The group agreed that the current 
draft is ready for WG Last Call.

3) Packet Selection

The Packet Selection draft (B) was discussed by the group.
Updates since the last draft were presented.  Refer to
the slides for the details of that presentation.  The
significant changes made since the last draft include:
  - better alignment with the framework draft
  - description of packet selection schemes updated
  - conformance changed so that one scheme must be supported
    but which one is up to the implementor
  - concepts of filtering and sampling aligned with framework
  - listed sampling techniques and parameters

The group was asked if the current list of packet selection
schemes is sufficient and there was agreement it is sufficient.

3.1) Open Issues

There are some details that need to be added to the document,
such as a description of hash-based sampling.  The information
model details will be moved to the report format document.
Details about which hash functions also needs to be resolved.
A mechanism for defining high level filter specifications is
needed.  There is some terminology that could be better aligned
related to the IPFIX metering process.  It is expected that
the next draft will be ready for WG Last Call.

4) Report Format and Export Protocol

A presentation on the IPFIX Report and Export protocol
was given.  Refer to the slides for details.  The IPFIX
Information Model and IPFIX Protocol documents are relevant
to the PSAMP report format and export protocol, and should
be read by the working group.

4.1) Open Issues

Separate documents are needed for the PSAMP Information
Model and PSAMP usage of the IPFIX protocol.  These
documents will rely on the IPFIX documents, and only add
enough details to support unambiguous conformance for
PSAMP purposes.  These documents are expected to be started
before the next IETF meeting in November 2003.

5) PSAMP MIB

A presentation on the PSAMP MIB was given.  Refer to the slides
for details.  The MIB structure follows the structure of the
framework and packet selection mechanisms.  There is a group
describing packet selection methods.  For each method, there
are objects which report the type, capabilities, and configured
parameters.  

There is a reporting group used to configure the addresses
of the report collectors.  There is an instance group, which
identifies the specific active sampling/reporting processes
that are active on the PSAMP device.  There is a group that
identifies the sampling methods supported by the device.
This needs to better align with the framework and packet 
selection terminology and selection methods.

5.1) Open Issues

The following open issues were identified:

  - Information about Filtering and Sampling Reports is 
    currently not included
  - Several sampling methods are not yet defined
  - Packet filtering needs to be added to sampling methods
  - The parameter set definition of sampling methods needs to 
    be checked carefully, some capability definitions are not
    yet complete.
  - Conformance statement and security considerations needed
  - Row status objects in writable tables needed 
  - Support for reporting to multiple collectors needed
  - Some descriptor name lengths exceed SMI recommendations

Two issues were resolved at the meeting:
  - Should there be support for more than two sampling parameter 
    sets per instance?   The group decided two sets is
    sufficient.
  - Should there be a single object for capabilities, using
    BITS syntax, or should there be multiple boolean objects,
    as in the current draft?  The group decided one BITS object
    would be better.

A new draft of the PSAMP MIB is expected about six weeks after
the IETF meeting.

6) Proposal on per-packet record export 

There was some time left at the end of the meeting, so a
presentation was added which proposes to add per-packet
fields to the IPFIX (or PSAMP) information model.  Some
new features, such as additional filtering of reports
based on packet contents and a global packet ID were
requested.

There was some objection to addressing this work in the
PSAMP WG and concern about the significant resources that
would be required on a PSAMP device to support these
features.

Note that packet selection is not affected, just the report 
process is impacted by this proposal.  Instead of the first N 
bytes, an export process would have to extract named fields
and maybe apply filters against the payload, to determine
which fields to include in the report.

Nobody in the group said they needed these reporting features.
It was suggested that RMON filtering should be used for
packet content filtering.  This proposal may be discussed
further on the WG mailing list.  It is possible that the
information model additions can be done independently of
the current PSAMP effort.