Re: [IPFIX] RFC 3550 jitter

Andrew,

This is a great point. It was also raised privately (off list) by one 
other responder.

Cisco already has a large number of jitter metrics which we export in 
enterprise-specific fields. RFC 3550 jitter was the only one we thought 
standardisable. I expect others have similar ES fields for their own 
jitter metrics.

One solution would be to use the same mechanism that I proposed for MIB 
export, ie Extended Field Specifiers.

ie, we'd have a single export ID for "jitter", to which an extension can 
be applied indicating which jitter it is, which implies how it's calculated.

See slide 7 here: 
http://tools.ietf.org/agenda/85/slides/slides-85-ipfix-2.pdf

P.

> Is it necessary to have an IE each possible jitter calculation and the
> document where that calculation is defined?  Seems like we could end up
> with a huge pile of jitter IEs.  Are there other calculated values that
> have need to specify how they were calculated?  PSAMP has
> selectorAlgorithm etc., applicationId has an embedded Classification
> Engine ID, do we need some sort of calculationTypeId for calculated values
> like jitter?
>
> -Andrew
>
> On 11/28/12 12:30 PM, "Paul Aitken" <[email protected]> wrote:
>
>> Dear all,
>>
>> I received feedback that the name should include "mean" and 'rfc3550',
>> since there are other jitter metrics which take into account all samples
>> rather than running average based last 16 samples as done by RFC3550.
>>
>> So the proposed names could be rfc3550JitterMeanMilliseconds,
>> rfc3550JitterMeanMicroseconds, and rfc3550JitterMeanNanoseconds.
>>
>> P.
>>
>>
>> On 28/11/12 15:25, Paul Aitken wrote:
>>> Dear IPFIX experts,
>>>
>>> I'd like to request an IPFIX IE for jitter from IANA. RFC 3550 defines
>>> a suitable "interarrival jitter". Unfortunately it's measured in
>>> "timestamp units":
>>>
>>>        An estimate of the statistical variance of the RTP data packet
>>>        interarrival time, measured in timestamp units and expressed as an
>>>        unsigned integer.
>>>
>>>
>>> Therefore it seems we may need multiple IEs: one for units of
>>> milliseconds, one for microseconds, one for nanoseconds...
>>> Else comparison of two jitter values would be meaningless.
>>>
>>> So I request your feedback on the following:
>>>
>>> Name: interarrivalJitterMilliseconds
>>> Type: unsigned32
>>> Semantic: quantity
>>> Description: interarrival jitter as defined in section 6.4.1 of RFC
>>> 3550, measured in milliseconds.
>>> Units: milliseconds
>>> References: [RFC3550]
>>>
>>> Name: interarrivalJitterMicroseconds
>>> Type: unsigned32
>>> Semantic: quantity
>>> Description: interarrival jitter as defined in section 6.4.1 of RFC
>>> 3550, measured in microseconds.
>>> Units: microseconds
>>> References: [RFC3550]
>>>
>>> Name: interarrivalJitterNanoseconds
>>> Type: unsigned32
>>> Semantic: quantity
>>> Description: interarrival jitter as defined in section 6.4.1 of RFC
>>> 3550, measured in nanoseconds.
>>> Units: nanoseconds
>>> References: [RFC3550]
>>>
>>> Thanks,
>>> P.
>>> _______________________________________________
>>> IPFIX mailing list
>>> [email protected]
>>> https://www.ietf.org/mailman/listinfo/ipfix
>> _______________________________________________
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