[metrics-team] How to establish identity on converted descriptors

[Karsten Loesing]

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Hi Thomas,

using "type + published + fingerprint" for those four descriptor types
sounds reasonable.  There will be edge cases of relays or bridges
publishing more than one descriptor in a given second, but those cases
are likely caused by a bug and those descriptors are probably not as
useful for statistical analysis anyway.  So, while digest may be the
best unique identifier you could find, a combination of existing
identifiers should be sufficient in practice.

Rest looks good.

All the best,
Karsten


On 21/06/16 12:38, tl wrote:
> Hi,
> 
> turns out the easiest way to distinguish relays, bridges and the
> respective extra descriptors from each other is the "digest" value
> (that so far we haven’t included in the conversion). After our
> conversation I realized that I’m not sure if "type + published +
> fingerprint" can't differentiate between descriptors just as good
> as "digest"? Problem is I’m not so fond of the idea of integrating
> the digest value just for the purpose of disambiguation. Since the
> other descriptors will have to rely on combinations of fields for
> disambiguation anyway couldn’t we go the same route with relays,
> bridges and extra descriptors?
> 
> There were other changes as well. For relay vote a combination of
> "type", "identity" and "valid after" guarentees uniqueness. For
> relay consensus and bridge status "type" and "valid after" is
> sufficient. Tordnsel/ExitLists can be identified by "type" and
> "downloaded", Torperf need a combination of "type", "source", "file
> size" and "start".
> 
> So the current state is:
> 
> relay         digest  (or type + published + fingerprint ?) 
> bridgeExtra   digest  (or type + published + fingerprint ?) 
> relayExtra    digest  (or type + published + fingerprint ?) bridge
> digest  (or type + published + fingerprint ?) relayConsens  type +
> valid-after bridgeStatus  type + valid-after relayVote     type +
> valid-after + identity tordnsel      type + downloaded torperf
> type + source + filesize + start
> 
> 
> Cheers, oma
> 
> 
> 
>> On 21.06.2016, at 08:06, Karsten Loesing <karsten at torproject.org>
>> wrote:
>> 
>> Signed PGP part Hi Thomas,
>> 
>> we briefly talked about identifiers yesterday.  Mind posting the
>> result?
>> 
>> All the best, Karsten
>> 
>> 
>> On 19/06/16 23:01, tl wrote:
>>> 
>>>> On 19.06.2016, at 19:30, tl <tl at rat.io> wrote:
>>>> 
>>>> We were discussing handling of duplicate descriptors during
>>>> the last metrics-team IRC chat. Thinking about it I became
>>>> aware that I’m not always sure how to establish the identity
>>>> of a descriptor in the first place. It’s easy for descriptors
>>>> that contain fingerprints (relay, relayExtra, bridge,
>>>> bridgeExtra). For the other descriptors I could imagine that
>>>> certain timesamps can serve as identifiers. I guess the type
>>>> information is always needed as a second part to guarentee
>>>> uniqueness of the identifier.
>>>> 
>>>> relay         type + fingerprint relayExtra    type + 
>>>> fingerprint relayVote     type + published (or valid-after?) 
>>>> relayCons     type + valid-after bridge        type + 
>>>> fingerprint bridgeExtra   type + fingerprint bridgeStatus
>>>> type + published torperf       type + start tordnsel
>>>> type + downloaded
>>>> 
>>>> Can soemone please comment if this makes sense?
>>> 
>>> 
>>> Okay, I can see for myself that it doesn’t. Relays and bridge 
>>> descriptors additionally need a timestamp to be unique since
>>> the fingerprint identifies only the router itself, at any point
>>> in time. OTOH vote  descriptors need an authority identifier.
>>> 
>>> relay         type + fingerprint + published relayExtra    type
>>> + fingerprint + published relayVote     type + identity +
>>> published relayConsens  type + valid-after bridge        type +
>>> fingerprint + published bridgeExtra   type + fingerprint +
>>> published bridgeStatus type + published torperf       type +
>>> start tordnsel      type + downloaded
>>> 
>>> That’s better but is it good enough? BridgeStatus, Torperf and 
>>> Tordnsel still seem underspecified to me.
>>> 
>>> 
>>> oma _______________________________________________
>>> metrics-team mailing list metrics-team at lists.torproject.org 
>>> https://lists.torproject.org/cgi-bin/mailman/listinfo/metrics-team
>>>
>>
>
>>> 
> 
> 
> 
> 
> 
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