[Commotion-dev] Commotion IP ranges for multiple mesh interfaces?

[Dan Staples]

On 05/29/2014 04:01 AM, miles wrote:
> I may just be confusing myself about how to best use OLSR. 
> 
> I ran into the problem while setting up a dual band router.  If I use the standard commotion setup, each radio thinks they are attached to the same 100.64 subnet, but they can't view the same hosts.  Olsr will eventually make this work. If I want to force traffic over the backbone, I need set the per interface weight accordingly. 
> Right?  
> I think this makes serval dependent on the olsrd routing table, which is unfortunate/redundant. 

For running multiple instances of olsrd, one for each separate network
you're setting up, that will have to be done manually as the Commotion
web interface doesn't support that. I haven't run multiple olsrd
instances on a node before so I'm not sure how they will handle both
updating the routing table. I imagine if each instance doesn't have
overlapping HNA networks, and perhaps doesn't receive routes to the same
subnets elsewhere, they won't clobber each other when updating the
routing table. But again, I don't know as I haven't tried.

As far as Serval relying on the olsrd routes, that's just a thing we
have to live with for now. We've been talking with the Serval folks
about a way to decouple serval-dna's built-in routing from the MDP
overlay network, but as of now there is no solution. They might be able
to shed more light on that matter.

> How do you handle mixed 5ghz and 2 ghz devices today when bridged over Ethernet?  

How do you mean? Right now, using the OpenWRT built-in menus (under the
Advanced tab in the new Commotion interface), you can use both radios
and set up virtual interfaces on each as you need. And you could add an
interface on the 2.4ghz radio and an interface on the 5ghz radio into a
bridge with the ethernet interface if you like.

> I was also thinking about segmenting the backbone for security reasons - an open 2.4 ghz mesh, and a  signed & encrypted OLSR mesh for the backbone. That would allow for trusted services like NTP and "secure" routing among backbone nodes. 
> So far, I haven't figured out how to partition olsr without quagga and a lot of pain in the middle.   
> 
> If splitting the IP space does make sense, how about. 
> 100.64.0/11 for stock commotion (32 Class Bs = thousands of nodes before collisions are likely. ) 
> 100.96.0/11 for "backbone" with either a different frequency or different security zone. 
> 100.127.127.0/17  broken into 8 /23s for point to point  links or very sparse networks (like long haul WAN repeaters). That's only  ~ 7 nodes before there is  a 1% chance of collisions, but 1/2048 is fair odds for an auto discovered private link. It may be  more efficient to require manual IP addressing .  Or even set aside one 10.x space ?

I suppose that could work, but again you'd need a new algorithm for
auto-generating IPs in each of those ranges if you didn't want to set
the IPs manually.

-- 
Dan Staples

Open Technology Institute
https://commotionwireless.net
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