Clarify Node definition for microscopic context

[renghardt]

From Jake's review, related to the "Node" definition in Section 2:

Just to clarify: is for example a DSCP-selected queue in a switch a Node under this definition? I think so, as it may have some specific relevant properties that are different from other queues, such as latency targets and capacity limits.

But as written the answer seems unclear to me, and I feel like it might cause confusion if used that way. Would it be helpful to include something this as an example too? I think the AS example shows some helpful scope in the sense that this aggregates to a macroscopic context, but if I'm understanding correctly that it's intended to be generalizable like this, I think it might be helpful to clarify that depending on the properties and dynamics under discussion, it can also be useful to slice to a more microscopic context than a whole device or virtual device.

Yes, a DSCP-selected queue in a switch can be a Node.

To illustrate that a Node is not necessarily a physical or virtual machine, but can be defined in a more microscopic context, we have already included a service function as an example. To make it clearer, we can also add "a single queue" as another example for a (virtual) Node.

[renghardt]

Comment from Med:

[Med] Another example we can add is the VRF or the more general concept of "VPN Node" defined in:

draft-ietf-opsawg-l3sm-l3nm-07:

VPN node: An abstraction that represents a set of policies applied on a PE and that belong to a single VPN service. A VPN service involves one or more VPN nodes. As it is an abstraction, the network controller will take on how to implement a VPN node. For example, typically, in a BGP-based VPN, a VPN node could be mapped into a Virtual Routing and Forwarding (VRF).