[Battlemesh] Session about multi-homed IPv6 mesh networks and auto-configuration

[Dave Taht]

On Tue, Apr 19, 2016 at 9:40 AM, Ferry Huberts <mailings at hupie.com> wrote:
>
>
> On 19/04/16 18:23, Juliusz Chroboczek wrote:
>>>
>>> We need metrics in the homenet protocols to be able to handle this.
>>
>>
>> Homenet uses Babel for announcing reachability, which has metrics.
>
>
> Yes, but AFAIK there are no provisions for announcing exit link bandwidth.
>
> We really need something like that to be able to choose the best gateway to
> use. This becomes especially relevant in mesh scenarios where nodes might be
> multiple hops away.
>
> As an example: a mesh node is 1 hop away from an exit link with very little
> bandwidth, and several hops away from an exit link with a very high
> bandwidth. Depending on conditions it might be advantageous to pick either
> one or the other. This is only possible when we know BOTH the exit link
> bandwidth and the mesh metrics.

I prefer to think about it as a congestion problem. If that local link
is entirely unused, and that gigE link saturated, which would you
chose?

> This becomes somewhat less relevant when using MP-TCP. Not very much however
> when there are many exit links since you generally don't want to use many
> many exit links in a MP-TCP session, especially on a mesh.

Source specific routing pushes the choice of exit link to the
application, which I like a lot. http://arxiv.org/pdf/1502.02402.pdf
for mosh was quite lovely (did it ever make mainline?), and mp-tcp is
not required - IF we could push source address selection into the
application for regular tcp (or quic), in a browser, something much
like happy eyeballs would suffice.

>
>
>>
>> Where Homenet is different from what you're used to is that it announces
>> all available gateways using source-specific routes, and hosts are
>> supposed to choose the gateway they use (by picking a given source
>> address).  See
>>
>>    http://arxiv.org/pdf/1403.0445.pdf
>>
>> Unless they snoop on Babel traffic, however, hosts have no information
>> about the metrics associated to individual prefixes.  Snooping on Babel
>> traffic is not difficult, but it is not defined by the Homenet
>> architecture,
>> since Homenet requires no host changes.
>>
>> -- Juliusz
>> _______________________________________________
>> Battlemesh mailing list
>> Battlemesh at ml.ninux.org
>> http://ml.ninux.org/mailman/listinfo/battlemesh
>>
>
> --
> Ferry Huberts
>
> _______________________________________________
> Battlemesh mailing list
> Battlemesh at ml.ninux.org
> http://ml.ninux.org/mailman/listinfo/battlemesh



-- 
Dave Täht
Let's go make home routers and wifi faster! With better software!
http://blog.cerowrt.org