Subject: [Drip] reqs review: Broadcast & Network RID general architectures

From: "Stuart W. Card" <[email-masked]>
Date: Sun, 4 Oct 2020 06:59:25 -0400

[email-masked] review major issue:

> - The descriptions for BRID and NRID are somehow unclear and seem not fully consistent throughout the document. Figures of their general architecture should be provided, e.g. in the section “overall context”.
> 
> - Reading the document, it seems that NRID and BRID share the same technical requirements / constraints (regarding security, privacy or types of attack) and that one can be derived from the other. Given that they are based on fundamentally different network architectures, this should be clarified. Their common features and differences should be highlighted, as well as the layer at which DRIP applies. In particular, this would help derivate the requirements needed at lower layers. 

Both RID means transfer the same information for the same purposes, but
in very different ways: one runs the application directly over the link
layer, the other uses the Internet; one defines message formats, the
other only a data dictionary of the elements of information, largely
agnostic to how they are transferred.

Should Figure 1 (general architecture) and Figure 2 (Network RID) from
the Architecture draft be replicated in the Requirements draft?

If so, should they be augmented with a figure showing a direct data link
(Broadcast RID over Bluetooth or WiFi, w/o IP, w/o intermediate nodes)
between an UA transmitter and an Observer's receiver?

Would such figures suffice or is something more needed?

It is difficult to say at which layer DRIP applies. The DRIP identifier
can be used at various layers: in Broadcast RID, it would be used by the
application running directly over the data link; in Network RID, it
would be used by the application running over HTTPS; and in RID
initiated V2X applications such as DAA and C2, it could be used between
the network and transport layers (with HIP or DTLS)...

-- 
-----------------------------------------
Stuart W. Card, PhD, Principal Engineer
AX Enterprize, LLC  www.axenterprize.com
4947 Commercial Drive, Yorkville NY 13495

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From: Robert Moskowitz <[email-masked]>
Date: Mon, 5 Oct 2020 09:33:01 -0400

On 10/4/20 6:59 AM, Stuart W. Card wrote:
>> - Reading the document, it seems that NRID and BRID share the same technical requirements / constraints (regarding security, privacy or types of attack) and that one can be derived from the other.

This is basically not true.  Broadcast security is harder than a 
pairwise Network security protocol.  Yes, what is done for broadcast 
DOES work for network but not the other way.

>>   Given that they are based on fundamentally different network architectures, this should be clarified. Their common features and differences should be highlighted, as well as the layer at which DRIP applies. In particular, this would help derivate the requirements needed at lower layers.

The commonality is the same data needs to be provided from the UAS. What 
differs is how and to whom.  Broadcast is to any observer within radio 
range.  Network is strictly between the UAS and USS.

The lower layers for broadcast are already provided by the CAA (well FAA 
and EASA have published expectations on this).  Network will be over the 
Internet.  Somehow.  And ICAO sees this different between UAS that are 
GRAIN members and UAS that are not.

> the network and transport layers (with HIP or DTLS)...
The datagrams for Broadcast RID are defined elsewhere (current CAA 
position is from ASTM).  Further the way these datagrams are transmitted 
over a small set of PHY/MAC are defined by ASTM.  DRIP is working within 
these datagrams.

For Network RID, the methods of communicating the ASTM data models from 
UAS to USS are left open.  We can define this from the IP layer up to 
the application (like we can develop a CoAP/CBOR standard).  I have 
already proposed part of this in my draft, and welcome help:

https://datatracker.ietf.org/doc/draft-moskowitz-drip-secure-nrid-c2/

Bob