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Re: draft PSAMP minutes
At 02:46 PM 4/8/2003 -0500, Alex Audu wrote:
>No one is proposing a hack configuration protocol. It has to be done right.
>Simply because
>it is non-trivial work doesn't mean it shouldn't be done. There are many people
>willing to do the
>work.
Here is item 6 from the charter, which is the only mention of
configuration:
6. Configuration and Management. Define a packet sampler MIB to reside
at the network element, including parameters for packet selection,
packet report and stream format, and export. Select or define a
communication protocol to configure/read this MIB.
I don't agree that there are many people in the PSAMP WG
willing to define a new protocol to configure/read MIBs.
From the mailing list and I-D activity, it does not seem
that the WG is ready to take on a big increase in work.
>Regards,
>Alex.
Andy
>Andy Bierman wrote:
>
>---X-----------------------------
>
>>
>> >Besides, why have two messaging paths, one for
>> >configuration
>> >and the other for data collection when you can have one do both functions?
>>
>> This is not a compelling reason either. Inventing a new
>> protocol requires new work to support it. Replicating all
>> the functions of configuration (e.g., security, access control,
>> data naming) is non-trivial. A hack configuration protocol
>> without any security is not a valid option.
>>
>> >Regards,
>> >Alex.
>>
>> Andy
>>
>> >Juergen Quittek wrote:
>> >
>> >> Dear all,
>> >>
>> >> Below please find a draft of the minutes of the PSAMP session
>> >> in San Francisco.
>> >>
>> >> Comments, corrections and extensions are very welcome!
>> >> If I do not get any feedback, I will submit them as they
>> >> are by the end of the week.
>> >>
>> >> Cheers,
>> >>
>> >> Juergen
>> >> --
>> >> Juergen Quittek quittek@ccrle.nec.de Tel: +49 6221 90511-15
>> >> NEC Europe Ltd., Network Laboratories Fax: +49 6221 90511-55
>> >> Kurfuersten-Anlage 36, 69115 Heidelberg, Germany http://www.ccrle.nec.de
>> >>
>> >> ==========================================================================
>> >>
>> >> PSAMP meeting on March 21, 2003
>> >> reported by Juergen Quittek
>> >>
>> >> The meeting had about 45 attendees.
>> >>
>> >> =====================================
>> >> Any Bierman on WG and document status
>> >> =====================================
>> >>
>> >> Andy gave an overview of the session: three documents are to be
>> >> discussed covering framework, packet selection and harmonization
>> >> with the IPFIX WG. For the first two documents he hopes they can
>> >> be delivered in May as planned. Between these two documents,
>> >> minor issues need to be clarified including terminology.
>> >> Working group last call is planned for end of April.
>> >>
>> >> The PSAMP MIB document was not on the agenda. Work on it will
>> >> start in April. Volunteers for writing the PSAMP MIB are still
>> >> welcome. Please contact the chairs.
>> >>
>> >> Conformance issues for PSAMP systems are to be discussed today.
>> >> Minimum requirements include a single observation point, a single
>> >> standard sampling algorithm and export using PSAMP format and
>> >> protocol.
>> >>
>> >> ====================================
>> >> Nich Duffield on the PSAMP framework
>> >> ====================================
>> >>
>> >> Nick reported on the changes in the PSAMP framework document
>> >> <draft-ietf-psamp-framework-02.txt> since the last meeting.
>> >>
>> >> The selection operation was just a binary decision, now it is
>> >> the selected packet. This simplifies expressing ordered composite
>> >> selection operations.
>> >>
>> >> Now, each selector keeps the number of input packets and reports
>> >> it as sequence number.
>> >>
>> >> Basic packet selection can be count-based or timer-based. Past
>> >> studies showed that count-based selection is more accurate.
>> >> Still both will be supported by PSAMP. Further supported selection
>> >> methods include random sampling, 1 in N sampling and hash based
>> >> sampling. There are more candidates, but it is an open question,
>> >> how much of them can be specified.
>> >>
>> >> Filtering is the selection based on packet fields and packet
>> >> treatment. Filtering will not be a mandatory feature of PSAMP
>> >> devices. Routers already do filtering with ACLs, but filtering
>> >> for PSAMP can be easier than filtering with ACLs.
>> >>
>> >> Composite selection operations are nice to have, but it is not yet
>> >> clear if we need complex composition capabilities. The current
>> >> proposal is to just offer either (1) first sampling, then
>> >> filtering or (2) first filtering, then sampling.
>> >>
>> >> It was under discussion whether there shall be a set of mandatory
>> >> packet selection methods or whether just a single arbitrary one
>> >> MUST be supported by a PSAMP device. But according to the
>> >> discussion during Andy's presentation the group agreed on a
>> >> single arbitrary one.
>> >>
>> >> Reporting MUST support the following reports:
>> >> - first N bytes of packet
>> >> - sequence numbers
>> >> - device interface serving as observation point
>> >> - attributes calculated during sampling: hash, timestamp, ...
>> >>
>> >> There were no changes in the export process, but there are some
>> >> expected depending on our evaluation of DCP and PR-SCTP, and on
>> >> the IPFIX protocol choice.
>> >>
>> >> Question by unknown person: How will the observation point be
>> >> specified? By logical or physical interface ID?
>> >>
>> >> Juergen, Andy: the physical seems to be always required, the
>> >> logical one can be optional. Anyway, the observation point need
>> >> to be clearly identified.
>> >>
>> >> ===============================
>> >> Tanja Szeby on Packet Selection
>> >> ===============================
>> >>
>> >> Tanja reported on progress with the document on packet selection
>> >> <draft-ietf-psamp-sample-tech-01.txt>.
>> >>
>> >> In conformance with Andy and Nick, Tanja stated that there are no
>> >> MANDATORY sampling schemes but if one is supported, than this
>> >> scheme need to be precisely defined by the standard and the
>> >> implementation MUST comply to this.
>> >>
>> >> Nick: We need to clarify if hash-based sampling is a kind of
>> >> content-based sampling?
>> >>
>> >> Is content-based sampling other than hash-based required at al?
>> >>
>> >> Andy: Does anyone have a strong feeling on whether to have no particular
>> >> scheme mandatory, but just the support of at least one of them? Please
>> >> send comments to the list.
>> >>
>> >> ==================================
>> >> Benoit Claise on relation to IPFIX
>> >> ==================================
>> >>
>> >> Benoit explained the similarities and differences in
>> >> architecture and terminology of IPFIX and PSAMP. Terminology
>> >> should be consistent between the two groups.
>> >>
>> >> Also mutual re-use of technologies is possible. The IPFIX WG
>> >> has chosen NetFlow version 9 as starting point for protocol
>> >> development. NetFlow v9 is template-based.
>> >>
>> >> Andy: at least one reporting template per observation point need
>> >> to be available in order to differentiate observation point.
>> >>
>> >> Juergen: There should be one report configuration per
>> >> observation point.
>> >>
>> >> Peter Phaal: There might be a problem with using templates
>> >> for PSAMP.
>> >>
>> >> Benoit: There should be no problem with templates.
>> >>
>> >> Andy: There is a problem with template-based reporting, because
>> >> variable length fields are not yet supported.
>> >>
>> >> Benoit: This was also discussed in IPFIX the day before and it
>> >> is identified as a shortcoming to be fixed.
>> >>
>> >> Unknown person: It looks like the group focuses on routers
>> >> and switches. Are workstations also in the scope?
>> >>
>> >> Andy: Yes.
>> >>
>> >> Unknown person: Why would the readable MIB be a MUST
>> >>
>> >> After a short discussion, read-only support of the
>> >> PSAMP MIB was not considered as mandatory. For small sampling
>> >> devices, supporting the MIB could be a too strong requirement.
>> >>
>> >> Nick pointed out some terms that need alignment between
>> >> PSAMP and IPFIX: field <-> attribute,
>> >> PSAMP device interface <-> observation point
>> >>
>> >> Nick: We should use SNMP for configuration
>> >>
>> >> Andy: How does the WG feel about using the IPFIX protocol for exporting?
>> >>
>> >> Unknown person: we have a measurement tool running that uses TCP-based
>> >> proprietary communication.
>> >>
>> >> It was agreed to continue this discussion on the mailing list.
>> >>
>> >> --
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>> >> archive: <http://ops.ietf.org/lists/psamp/>
>> >
>> >
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>
>
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