[Commotion-dev] Throughput advantage to 802.11s support

[Dan Staples]

On 02/08/2013 07:40 PM, L. Aaron Kaplan wrote:
> There are advantages to having a layer 2 mesh: 
>  * zeroconf works out of the box
>  * your windows shares will appear everywhere (is that good or bad? ;-) 
>  * the whole thing is essentially one big LAN -> this reduces complexity
>
> Of course, you have the disadvantage of potentially lower scalability.
The one thing I worry about with a layer 2 mesh, like you describe, is a
lack of control over how far you want certain traffic to go. For
instance, I recently wrote a service advertisement system for Commotion
that uses Avahi/mDNS. Since certain services won't work well over
several hops (like streaming media, perhaps), I'm writing a OLSRd plugin
that sets the OLSR packet's TTL value to be the max number of hops the
service wants to be seen. In other words, an application that only wants
to be seen a maximum of 3 hops away will have its mDNS advertisement
sent in an OLSR packet with TTL=3. That way the service advertisement
won't be seen by any and all nodes that the host node can make a route
to, rather only the ones within a specific radius. (For reference, we
currently use the p2pd plugin to propagate multicast traffic, which has
a hardcoded TTL value of 5, I think).

Would a layer 2 mesh, with everyone on "one big LAN", be able to control
traffic propagation in this way?

And having your windows shares available everywhere on the mesh sounds
like a ne'er-do-well's dream ;)

Dan

-- 
Dan Staples

Open Technology Institute
https://commotionwireless.net