----- Forwarded message from Jeremy Lakeman <jeremy@servalproject.org> ----- From: Jeremy Lakeman <jeremy@servalproject.org> Date: Tue, 27 Nov 2012 11:10:26 +1030 To: serval-project-developers@googlegroups.com Subject: Re: [serval-project-dev] Re: Adding GPS location to IPv6 header Reply-To: serval-project-developers@googlegroups.com Allocate an IPv6 private network range using a scheme like this; http://tools.ietf.org/html/draft-hain-ipv6-geo-addr-01 Probably with around 36 bits (100m) of precision, leaving the rest of the /64 to flag that it's private and geographically based. Internet gateways have their own "real" /64. Internet traffic would be routed to the correct gateway based on the network of the source address. If each device uses the same 64bit host id on each network. Local mesh route calculations can be based on a single main address per device, with an additional routing entry added for each network we believe that host should have. A protocol like SCTP will also allow both parties to change networks without needing to re-establish links. Then the biggest scalability problem for routing packets world-wide to an individual is a directory service for publishing and resolving current network locations. On Tue, Nov 27, 2012 at 9:40 AM, Eugen Leitl <eugen@leitl.org> wrote:

----- Forwarded message from George Herbert <george.herbert@gmail.com> -----

From: George Herbert <george.herbert@gmail.com> Date: Mon, 26 Nov 2012 14:51:57 -0800 To: William Herrin <bill@herrin.us> Cc: Eugen Leitl <eugen@leitl.org>, nanog@nanog.org Subject: Re: Adding GPS location to IPv6 header

The utility of this is somewhat moderated by limited geographical mobility while a phone's active in a single session. One rarely drives from San Francisco to LA typing all the way on their smartphone data connection, for example.

To the extent that you may apply IP ranges to wider geographical areas, and limit the search space to a few % of the total, beyond which devices get a new address pushed as they travel, this is entirely manageable without the new header.

Some services dislike the endpoint renumbering like that, and some connections go kerfluey, but most web based activities handle the endpoint getting a new IP just fine; this is what cookies are for. Your SSH connections will remind you that you should be using screen, or not type and drive. But the CHP and road hazards will already do that.

Eventually being allowed to use air-to-ground cell data on airliners will be slightly worse, but again, most protocols shrug at this problem.

-george

On Mon, Nov 26, 2012 at 2:36 PM, William Herrin <bill@herrin.us> wrote:

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On Mon, Nov 26, 2012 at 10:20 AM, Eugen Leitl <eugen@leitl.org> wrote:

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On Mon, Nov 26, 2012 at 12:56:52PM -0200, Carlos M. Martinez wrote:

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Just for redundancy's sake: No, L3 is **not** the place for this kind of information. L3 is supposed to be simple, easy to implement, fast to

I agree. You need to put it into L2, and the core usage would be for wireless meshes. Consider cases like Serval or cjdns, which run on Android headsets and equivalent embeddeds. Technically you wouldn't need GPS everywhere if you could do ~m scale time domain reflectometry in free space. It is possible to build a local contiguous map via mutual time of flight triangulation (actually, just visibility gives you a very good hint).

Actually, I think you just articulated the first use for Ammar's idea that's not either wrong, absurd on its face or obviously better handled at a different location within the protocol stack.

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.

There are some assumptions in this model which are problematic. Key ones are:

1. Only valid as an interior gateway protocol (IGP). Geographic routing has been proven false for an EGP because it induces traffic to cross links for which neither source nor destination has permitted access.

2. Requires the application at the landed end to copy the IP option information into the outbound packets as well. This behavior is not presently guaranteed.

3. Assumes that the device will originate communication, receiving only replies from the landed end, or will use some intermediary to communicate current geographic information if inbound origination is required.

At any rate, I think that discussion of adding a geographic option header to IPv6 should be tied up in the discussion of a routing protocol which critically depends on its presence and can't reasonably be built another way. Otherwise when a needful use case finally comes along, you'll discover that the option's rules of operation don't adequately enable it.

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

-- -george william herbert george.herbert@gmail.com

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