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EOS: Time-based Aggregate MIB proposal
- To: "firstname.lastname@example.org" <email@example.com>
- Subject: EOS: Time-based Aggregate MIB proposal
- From: Glenn Mansfield Keeni <firstname.lastname@example.org>
- Date: Mon, 09 Sep 2002 18:21:30 +0900
- Organization: Cyber Solutions Inc.
- User-agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.0.0) Gecko/20020530
(BAs an extension to the MO aggregation approach proposed in a
(Bcompanion document (draft-glenn-mo-aggr-mo-02.txt) we are
(Bproposing time-based aggregation of MOs.
(BThe idea is simple - it uses a MIB-based approach to define a
(Btime based aggregation object (TAgMO).
(BA user defines a TAgMO instance by specifying the MO instance
(Bthat needs to be sampled, the sampling interval and the desired
(Bnumber of samples that will be included in one TAgMO instance.
(BThe value of a TAgMO instance will include the timestamp
(B(sysuptime) at which the first sample was taken. With the
(Bdefinitions done the user can do an SNMP 'get' on an instance
(Bof the TAgMO to fetch the values of the constituent MO instance
(Bsampled at the specified intervals.
(BThe document - draft-glenn-mo-taggr-mib-00.txt has been posted
(Bon 7th September, 2002, and should be in the archives shortly.
(BIt deals with aggregation of several samples of the same MO
(Binstance sampled at user-defined intervals a user-defined
(Bnumber of times. [The document is also available
(BThe changes since the presentation at the last Yokohama-IETF
(Bare - a 'tAggrErrorRec' object is added. This takes care of
(Bmissing data and errors. It contains a list of <moIndex, moError>
(Btuples to indicate the exceptions that occured in fetching
(Bthe aggregated data. The moIndex represents the position of
(Bthe MO instance in the aggregated-MO value and moError
(Brepresents the error encountered.
(B [Note: only exceptions are represented in tAggrErrorRec]
(BThis tAggrMIB is most useful in getting information at regular
(Bintervals (secs, decisecs, centisecs, millesecs.. ) albeit at
(Bdelay which is the lower bounded by the product of the sampling
(Binterval and the number of samples in a TAgMO.
(BThe advantage of the TAggrMIB approach is that it provides maximal
(Bcompression. A single OID of the aggregate MO instance suffices
(Binstead of the OIDs of the constituent MO instances.
(BSo, how does this relate to and compare with other proposals ?
(BThe RMON-HistoryTable does record the time development of an
(BMO instance. But
(B o for fetching the data one has to go through the standard
(B laborious practice of using SNMP 'get's (or one of its variations)
(B involving the OID and value of every instance of the object.
(B (That is what we are complaining about!)
(B There is NO savings on Bandwidth, no compression.
(B o the smallest interval is limited to 1 sec .
(BLet me have your comments.