Re: [Int-area] Meaning of Identifier, Locator, and Address (was Continuing the addressing discussion: what is an address anyway?)

"Joel M. Halpern" <> Fri, 04 March 2022 19:39 UTC

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To: Toerless Eckert <>, Dino Farinacci <>
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Subject: Re: [Int-area] Meaning of Identifier, Locator, and Address (was Continuing the addressing discussion: what is an address anyway?)
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I do not believe the community has an agreed definition of identifier or 
locator.  We do have some relatively common usage for locator.  As far 
as I know there is no fully acurate and written down definition even for 

Note also that while Dino likes LISP for lots of things (for good 
reason), the LISP working group has been working to move the LISP RFCs 
to Proposed Standard with descriptions of usage that are for particular 
use case (not limited domains, but specific uses).  While originally 
developed to address Internet-Wide scaling problems, that is NOT what 
the PS documents cover.


On 3/4/2022 6:39 AM, Toerless Eckert wrote:
> On Thu, Mar 03, 2022 at 09:28:23AM -0800, Dino Farinacci wrote:
>>> of its address structure helps the underlay to locate the entity (xTR) that the
>>> address is assigned to (xTR). So the name 'locator' is 'just' a good
>>> name for what LISP calls/uses the address for, not for how the under
>>> itself would maybe call the address or use the address for.
>> Well the locator you put in an outer header destination address is called/used/assign to whatever the rules of the underlay are. If the underlay is ethernet, then its a 6-byte address where the high-order 3 bytes is an organizational ID, just to cite an example.
> Indeed.
> I have not seen an answer to the question i posed earlier in the thread:
>   whether and if so what general (not technology specific) definition of locator
> and identifier the IETF may have. But i have seen a lot of confusion about
> it and people shying away from using these terms.
> If (as i think) we do not have a commonly applicable definition of locator/identifier
> (beyond its use in indivdual technologies like LISP), then i think this is because
> folks who tried to apply these terms (incorrectly) may have failed to
> see the difference between what an address is and what someone (like an
> application) calls it (/uses it for). In that respect the reference to
> the White Knight in IEN19 is very helpful to remember.
> Cheers
>      Toerless
>> Dino