Re: [Int-area] Some thoughts on draft-yong-intarea-inter-sites-over-tunnels

[Joe Touch <[e-mail]>]

Hi, Fred (et al.),


On 11/30/2016 12:51 PM, Templin, Fred L wrote:
> Hi Joe,
> ...
> I didn't mention route optimization. With AERO, route optimization is what happens
> when the tunnel ingress switches from an egress that is on a suboptimal path to a
> different egress that is on a better path. 
That's internal to the tunnel itself, related to the fact that your
tunnel is multipoint and treats all egresses as valid.

That's another feature, but again it's hard to see where that would be
discussed. It's closest in spirit to egress determination in BGP or
LISP, and has no clear relation (AFAICT) to INTAREA (expertise or
purview). However...

> Due to the link nature of the NBMA overlay,
> that switching is accomplished through the use of IPv6 ND Redirect messages the
> same as would occur on a physical link (and in the same spirit as published in RFC6706).
I don't think I would call that routing either when it happens in a
regular network or inside an NMBA tunnel.

> That is why I ended up agreeing with you that fully embracing fragmentation is the
> only way to truly handle tunnel MTU, because without fragmentation an MTU that
> worked over the suboptimal path might fail over the new path once route
> optimization is employed.
>> And traffic engineering is easy
>> in a tunnel *if* it's supported in the base network over which the
>> tunnel operates, and impossible otherwise.
> Traffic engineering as in allowing the Client to select both the outbound underlying
> interface for outbound traffic and the inbound underlying interface for inbound
> traffic. 
A tunnel ends at interfaces. Client determination of interfaces happens
separate from a tunnel, IMO.

> So, a device that has both cellular and WiFi can send and receive packets
> with different TOS markings over both interfaces simultaneously (e.g., TOS '1' goes
> out over cellular, TOS '2' goes out over WiFI, etc.) and respectively for the
> inbound direction.

That's the job of interface selection in the host, which is already
specified in RFC1122 and extensions. Are you suggesting a change to
that? If so, it seems like it's completely orthogonal to the use of
tunnels as interfaces.

>
>> I'm not claiming this wouldn't be useful.  I'm saying that we need to
>> know what problem it solves to know where to home it.
> I have identified two very important use cases relating to aviation. 
You've defined a customer, IMO - which is great, but short of taking
this to an aerospace forum, it doesn't really help me understand where
in the IETF it should be discussed.

> So, the fortuitous
> selection of the AERO acronym now seems quite appropriate. We are also using it for
> mobile VPN management for corporate enterprise mobile device users (cellphones
> and tablets), and we are planning to release source code soon.

That's all good news, but I'm still left not quite understanding where
in the IETF this should (or could) be handled. We don't really have a WG
for creating tunnels and I'm not sure INTAREA should serve as  a default.

Joe