[Int-area] question about xping (draft-bonica-intarea-eping)

[Sowmini Varadhan <[e-mail]>]

Hi,

The draft says 
   ".. the destination and probed
   interfaces must be local to one another (i.e., both interfaces must
   belong to the same node)."

However, virtualization raises some questions about how this should work,
and maybe the draft should nail down some of the details with more 
clarity.

What if the probed interface is assigned to a different VRF than the
destination interface? e.g, What is the expected xping response
if I receive 
     # xping-I red0/0/0.0 10.10.10.1
on interface blue0 in the "blue" vrf, and red0 is in "red" VRF?
Does the answer change if the destination interface is on the
management VRF?

similar question for other forms of virtualization, e.g,,
What if the probed interface is assigned to a different 
network-namespace than the destination interface of an xping req?
Does it matter if the above xping is received on the default 
network namespace vs some other network namespace? 

One could argue that all the physical intefaces are owned by the "node"
(the management VRF? default netns?) but virtual interfaces like
tunnels and macvlans are a grayer area (unlike physical interfaces,
the latter do not default back to the mgmt VRF or default netns when
the virtual object is destroyed, so their ownership is unclear).

How should xping work in the face of virtual interfaces, e.g.,
the linux macvlan? How does it work when an interface is renamed?
Will xping allow me to probe for "tun0" or "Portchannel1"?

--Sowmini