Re: [Drip] HHIT field order

[Alexandre Petrescu <[e-mail]>]

Le 05/10/2020 à 14:56, Robert Moskowitz a écrit :
> This note is going to ask for thoughts on the order of the fields in a 
> HHIT.  Either
> 
> Prefix | Suite ID | RAA | HDA | HI Hash
> 
> or
> 
> Prefix | RAA | HDA | Suite ID | HI Hash
> 
> =================
> 
> In drip-uas-rid, I define the HHIT fields, as I did in 
> draft-moskowitz-hip-arch-02 in '01, as follows:
> 
>     A HHIT is built from the following fields:
> 
>     *  28 bit IANA prefix
> 
>     *  4 bit HIT Suite ID
> 
>     *  16 bit Registered Assigning Authority (RAA)
> 
>     *  16 bit Hierarchical HIT Domain Authority (HDA)
> 
>     *  64 bit ORCHID hash

I do not understand why we need to fix in stones these limits.

In particular, the 64bit ORCHID hash could be as well 66 or 63.

A more flexible stone-setting would be:

- 3 bits from IANA
- m bits for prefix
- n bits for interface ID
- 3+m+n must equal 128; m and n at the discretion of deployer.

Alex

Alex

> 
> 
> But I am proposing a different arrangement in the ICAO/GRAIN IPv6 
> scheme.  First a bit about GRAIN.
> 
> The GRAIN network is for Commercial-Civil aviation:
> 
> "1.2    The network enabling the IATF, the Global Resilient Aviation 
> Interoperable Network"
> (GRAIN), is envisioned as an aviation only (dedicated) IPv6 overlay 
> network on a series of underlying
> networks and supporting network services."
> 
> In some doc that I can't find right now this is limited to 
> commercial/civil aviation.  Further we have:
> 
> "[Please note that all recreational drone operation within Line Of Sight 
> (LOS), Class G airspace are not included in this schema. Recreational 
> drones using point-to-point LOS Command and Control (C2) are outside the 
> scope]"
> 
> So there is a potential and almost for sure bifurcating split in UAS 
> networking.  This does not impact Broadcast Remote ID, but it does 
> impact Network Remote ID.  The actual Remote ID SHOULD be the same for 
> each mode.  (Stu does the reqs say this?)
> 
> The regulators are going to have to figure out the demark.  Are 
> Police/Fire and Small Business like photographers and realtors in GRAIN 
> or out of GRAIN.  It will be interesting, as I suspect it will be a 
> higher cost to be in GRAIN, but there are some advantages to participants.
> 
> I should provide an aside here that the GRAIN prefix plus "platform 
> type" could be /20 so the following reflects this.
> 
> I added HHITs into the GRAIN addressing scheme, minimally for 
> commercial/civil UAS usage.  It could be used for more than UAS within 
> GRAIN.  In doing this I came to thinking two reasons for altering the 
> field order.
> 
> I put the Suite ID after the HID:
> 
> "ICAO DELEGATED NETWORKS /16 FOR PLATFORM TYPE 13 – Hierarchical Host 
> Identifier Tags (HHITs)
> /16 IANA Prefix Addressing Scheme
> 
> Bit #        Field Length        Purpose
> 1 – 16        16            ICAO IPv6 prefix
> 17 – 20        4            Platform type = 13
> 21 – 36       16            GRAIN HHIT RAA
> 37 – 52       16            GRAIN HHIT HDA
> 53 – 56        4            HHIT Crypto Suite
> 57 – 128      72            HHIT HI Hash
> 
> A HHIT Registered Assigning Authority (RAA) will apply for GRAIN 
> membership and be allocated a /36 prefix from this type with their RAA 
> GRAIN number being used in the 16 bits after the platform type. The RAAs 
> will then accept HHIT Hierarchical HIT Domain Authorities (HDA) as 
> sub-members and allocate to them /52 prefixes.
> 
> These HDAs will accept registration from UAS of HHIT Crypto Suite/HI 
> Hash per the IETF DRIP UAS-RID documents using a 72 bit hash. GRAIN HHIT 
> addresses may be for the life of the UAS or may be registered for only 
> some operational period."
> 
> Note, I do NOT envision different Crypto Suites by HDA.  And:
> 
> "A .01% hash collision probability occurs after ~1 Billion HHITs 
> registered (based on the 72 bit hash size) with an HDA. This increases 
> to 1% with ~10 Billion HHITs registered. If an HDA’s business model is 
> to provide a per operation HHIT for delivery UA, and supports a 
> clientele of 1 Million UA making 10 deliveries per day, then the HDA 
> will reach the .01% level in 100 days of operation.  Thus an HDA 
> provider in this type of business may request a block of 128 HDAs from 
> its RAA."
> 
> ========================
> 
> The importance here is putting the Crypto Suite and HI Hash together and 
> the Prefix and aggregation information at the front.  This is good for 
> filtering policy.  It also makes sense in grouping the HIT specific 
> parts and the prefix parts.
> 
> But does it cause any coding or other challenges.  Adam seems to think 
> so and so far he is the only coder active...
> 
> I look forward to a lively debate on this!
> 
> Bob
>