Hi Joe, I am looking at multilink nodes like manned aircraft and unmanned aerial vehicles that may have many active aviation data links, e.g., SATCOM, LDACS, 4G, AeroMACS etc. The links will be either available or unavailable at various phases of flight. But, AERO lays down a single IP layer interface (the aero0 interface) so that the aviation data links are seen as underlying interfaces each having one or more addresses. These underlying addresses are then seen as the L2 addresses for the AERO interface.
Underlying interfaces may come up and go down dynamically during a flight, and their addresses may change dynamically, e.g., if they hand over from cell tower A to cell tower B. It is AERO's job to take care of any mobility related links and always keep neighbors informed of the current L2 addresses and availability. But, it all still looks like a single interface (aero0) to the IP layer. Thanks - Fred From: Joe Touch [mailto:[email protected]] Sent: Tuesday, December 06, 2016 1:59 PM To: Templin, Fred L <[email protected]>; Lucy yong <[email protected]>; Brian E Carpenter <[email protected]>; [email protected] Subject: Re: [Int-area] Some thoughts on draft-yong-intarea-inter-sites-over-tunnels On 12/6/2016 1:46 PM, Templin, Fred L wrote: If there are multiple interfaces, why would it pick aero0? And what would its QoS be? It can't have a single value, so the main IP forwarding code can't decide between aero0 and other interfaces. The IP forwarding table has an entry such as: 2001:db8::/32 -> aero0 Meaning that any IPv6 packet with a destination that matches 2001:db8::/32 *and for which no more-specific route exists* goes out interface aero0 unconditionally. The packet will have a TOS value, and it is that TOS that guides the aero0 interface on how to portion traffic over the underlying interfaces. The problem is that this makes it impossible for the IP forwarding table to control which aero0 encaps is used, thus which QoS it gets. I.e., the main IP forwarding can't take QoS into account. I understand that Aero can do the right thing, but only with the packets it already has. It can't say "oh, I don't have a QOS for that, let me give it back to the main IP forwarding for another interface". If you have only one link, sure - there's no problem. But if you have more than one (which is much more typical, even for hosts), then you do. Joe
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