Re: Extending a /64

[Tony Whyman <[e-mail]>]

On 16/11/2020 14:55, Alexandre Petrescu wrote:
>
>
> Le 16/11/2020 à 15:38, Tony Whyman a écrit :
>> This discussion seems to have gone off in the wrong direction. There 
>> are no ICAO applications that foresee aircraft to aircraft 
>> communication using datalink.
>
> Eh?  Maybe with LDACS? draft-ietf-raw-ldacs-05 "5.2.2.  Air-to-Air 
> Extension for LDACS"
>
> Alex

Quoting from the internet draft

"Direct A2A communication between aircrafts in terms of ad-hoc data
    networks is currently considered a research topic since there is no
    immediate operational need for it, although several possible use
    cases are discussed (digital voice, wake vortex warnings, and
    trajectory negotiation) [BEL2019].  It SHOULD also be noted that
   currently deployed analog VHF voice radios support direct voice
    communication between aircraft, making a similar use case for digital
    voice plausible.

    LDACS direct A2A is currently not part of standardization."

The key phrases are "research topic" and "not part of standardization".

My understanding is that this extension is for line of sight 
communication and no internet functionality is required. You are also 
looking at applications that are naturally multicast. For example, 
existing analogue voice is broadcast and A2A LDACS voice would need to 
be similar in characteristic.

>
>  The underlying set of applications is:
>>
>> 1. Controller to Pilot Datalink Communication (CPDLC) - the name says 
>> it all
>>
>> 2. Automatic Dependent Surveillance (ADS) - allows an ATS Provider to 
>> monitor an aircraft's position and intent.
>>
>> 3. Flight Information Services (FIS) - allows a pilot to pull 
>> information (e.g. on runway conditions).
>>
>> TCAS also exists as a collision avoidance system and this does use 
>> air-to-air communication. However, this is a rider on the Mode S 
>> surveillance radar and is not IP based.
>>
>> On 16/11/2020 14:30, Philip Homburg wrote:
>>> However, this seems to be a case of doing things at the wrong level. 
>>> If aircaft
>>> use IPv6 to communicate then obvious they need unique IPv6 
>>> addresses. However,
>>> each plane only needs to know its own address. Any time a plane 
>>> communicates
>>> with an unknown plane, they can exchange higher level identities.
>>
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