[Ndn-interest] Freshness & Latest Content

[Junxiao Shi]

Hi Urs

I have some conceptual questions about freshness and how to ask for latest
> content.
>
>
>
> Imagine 2 properly versioned versions of /nytimes/frontpage (properly in
> the sense of “larger” version = “newer” version, according to [1]):
>
> format : contentName | freshnessPeriod
>
> /nytimes/frontpage/v100 | 100ms [stored at cache X somewhere between
> requester and producer]
>
> /nytimes/frontpage/v105 | 300ms [stored at producer]
>
>
>
> I assume that if a user does only know about the contentName (prefix), but
> not about the latest versionNumber, he/she asks for
>
> Interest: /nytimes/frontpage | CanBePrefix=true | MustBeFresh=true
>

Yes, that's what consumer should ask for.


> Question 1:
>
> Is it correct that this Interest is satisfied by cache X because there is
> a prefix match on the contentName and a freshnessPeriod > 0?
>

Yes, X will return /nytimes/frontpage/v100 until it becomes non-fresh.


> Question 2:
>
> Assuming the answer to Q1 is ‘yes’ and that the reuqester does NOT know
> the latest versionNumber, is there really no possibility for the requester
> to get the globally latest version v105 directly from the producer?
>

It is possible but requires changes on producer. See https://redmine.named-
data.net/issues/4396#note-1


>
>
> Question 3:
>
> Assuming that the requester KNOWS the latest versionNumber (from some
> miraculous oracle), I guess she/he can simply ask for (/nytimes/frontpage/v105
> | CanBePrefix=false | MustBeFresh=true). Correct?
>

Yes, the Interest should have version number if the consumer knows it.


Yours, Junxiao
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