[OLSR-users] Default routing question

[John Gorkos]

Replies inline, thanks for the quick response.

On Friday 26 March 2004 23:18, Andreas Tønnesen wrote:
> Hi,
>
> A most interesting project! My comments inline.
>
> John Gorkos wrote:
> > I have a project involving a large number of WRT54G routers running linux
> > w/ OLSR.  Perhaps 1 in 10 of the routers will have a backhaul to the
> > internet, the rest will use these internet connected routers as gateways.
> >  The kicker is this:  I want to have a single configuration that works on
> > all routers, regardless of whether they are internet-connected or not. 
> > Is this possible with the current OLSR imlpementation?  From what I've
> > been able to decipher, the OLSR daemon finds out from the configuration
> > file whether or not it is a "default" router.  I need to determine this
> > dynamically, because I don't know yet which routers get an internet
> > connection and which ones don't.
>
> IMO you should create a startupscript that checks wether the node has a
> internet route avalible. This check could easily be done inside the olsr
> daemon - but IMO this is not olsrs job. Modularity! :)
But what if a route becomes available while olsrd is running.  For example, I 
plug a DSL modem into the WAN jack of my WRT54G.  It detects the insertion as 
a hotplug event, runs the DHCP client and receives an IP address and a 
default route.  In my perfect world, olsr would "see" this and reconfigure 
itself as a gateway node.  Am I pipe-dreaming?
>
> > All told, the mesh will contain 50 routers initially, with about 50 more
> > in six months.  Is OLSR the right tool for the job?
>
> What kind of mobillity do you expect to see? And what kind of density?
> Anyways - to me this souds like a job for olsr. Olsr is very well suited
> for dense ad-hoc networks.
I expect to see little mobility in the network.  The project is to provide 
WISP access to an apartment complex.  For a variety of reasons, I have 
rejected the traditional hub-spoke network in favor of the mesh.  I will be 
adding/removing/moving nodes at a rate of less than 1/week after roll-out.
The radios will be mounted in the attics of each building, and each building 
has either 2 or 4 tenants.  Because of the ability to split out each of the 
LAN ports on a WRT54g into individual VLANs, I can use one radio on up to 4 
tenants.  This drives the cost/user down, and allows me to splurge by putting 
radios in buildings where there are no tenants today, but may be in six 
months.  Obviously, this strengthens the mesh.  The entire complex occupies 
approximately 2 square KM.
>
> Remember that you can tune the message-emission intervals to suit your
> mobillity-degree. If mobillity is high the HELLO(and other) intervals
> should be small.
So in a fairly static network, is the converse true?
>
> I intend to implement a plugin that allows one to update theese values
> at runtime.
I would be happy to test, especially if it includes the ability to default 
rotue out of the mesh (is that the proper terminology?)
>
> Again - this will be a _very_ interesting real-life experiment! Keep us
> updated on your work!! When do you expect to do this?
We have 20 WRT54Gs delivered, with 20 more on order.  We have the backbone and 
all server equipment in place, and a tower with carrier-grade backhaul gear 
on order, with a installation date of 10 days from now.  I intend to start 
installing radios NLT 15 April, 2004.  the only piece of the puzzle not 
completely shaped is the final firmware image.
  I noticed that g/w address is one of the few parameters that MUST be set in 
the configuration file vs on the command line.  Is there a reason for that?

Thanks again,
John