On Mon, Nov 26, 2012 at 5:46 PM, Harald Koch <chk@pobox.com> wrote:
On 26 November 2012 17:36, William Herrin <bill@herrin.us> wrote:
Suppose you have a large single-owner mesh network, such as a folks walking around with cell phones. If you want them to have a stable layer 3 address (and you do) then you're handling what amounts to /128 routes for tens of millions of devices. If you can guarantee that any packet *to* that address also contains a rough geographic location then you can discard any routes internally once they're more than a short geographic distance from the origin and route on the geography until you're close enough to find a specific /128 route. Tens of millions of routes is no problem if no single router needs to know more than a few thousand of them.
By putting geographic location at layer 3, you're also handling it end to end which means you don't need a stateful border device to track the current location of all of those /128 routes. The device itself doesn't need to add location if it doesn't have the data; it's good enough for the receiving tower to attach a rough location.
This also naively assumes that wireless network topology correlates with geographic location. Any radio engineer (or cell phone user) can explain why that doesn't work.
No. It assumes that the /128 route propagates far enough that every router (read: radio tower) operated by the service provider within the rough geographic locality has that route so that wherever the packet lands in the general area, it can make its way to the origin router currently talking to the device. It makes no assumptions about the particular path or paths between those two routers which could be terrestrial radio, satellite, wired or even a VPN across who knows what Internet path. It does set a requirement on the network architecture that at least one such path must exist: network partitions appear deadly to this architecture. I'm not saying this is a good idea. I'm just saying it's a legitimate topic for research and investigation which, if it shows any promise, would support the addition of a geolocation option header to IPv6's layer 3. By contrast, Ammar's other rationale for why to put it there (common interest at layer 7) aren't legitimate reasons for adding data to layer 3. Regards, Bill Herrin -- William D. Herrin ................ herrin@dirtside.com bill@herrin.us 3005 Crane Dr. ...................... Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004