What about multi-segment devices with no UND connections?

[BenGardiner]

from @jmaag15 in #36

consider: can an intentional gateway move information from a TND to another TND (while not attached to an UND )? Have we covered that use case in these requirements?

[BenGardiner]

Discussed at the 20220601 VCRWG meeting:

@jmaag15 you are correct: the definitions of 'gateway' -- both intended & unintended -- here make no account of multi-segment devices that have no UND connections.

When we move to assigning requirements to the device classes of https://github.com/nmfta-repo/nmfta-vehicle_cybersecurity_requirements we will need UND-connected gateway requirements (for classes 1 and 2) and no-UND multi-segment devices (class 3). We're starting to rub up against the friction between this experiment of a small set of security requirements and the whole elephant we need to eat for the truck matrix.

We could do a pass of the security requirements here and partition them into the requirements that apply to no-UND multi-segment device plus those additional requirements on UND-connected devices.

When we do the larger truck matrix work, we will need to do that excersize. Captured there as nmfta-repo/nmfta-vehicle_cybersecurity_requirements#24