On Thu, 2007-01-11 at 12:25 -0800, Rajesh Narayanan wrote:
> :-)
> 
> This is precisely the question that I have been myself thinking since
> yesterday. I thought of going back to routing fundamentals to see if
> there is a good answer. So far I have not been able to think of

Actually Andreas delivered the two possibilities in his answer. One is
below and the other is: Take dedicated nodes for this.

>  anything except a 'not so clean hack' that would sound soemthing like
> this: 
> 
> 1. Write a script to ping (dyn-gw already does this) on the default
> WAN interface.
> 2. If Pings succeed dont do anything
> 3. If ping fails then delete the default route.
>     - This is the part you were talking about. HOW DO I RECOVER?? 
>     - Since if I delete the route then the pings are not going out of
> this interface anyways.

The other solution (see Andreas email) is to add (low priority) host
routes to known-outside ping targets - the ones which are used to decide
if we have an uplink or not.

> 4. The hack is as follows:
>     - every 5 mins add the default route.
>     - test ping through that interface
>     - if successful then leave it 
>     - else, delete the default route again.
>
> I know this is BAAAAAAAAAAAD, but all I want is that I should use the

I (also) have some bad feelings about this:
IMHO this is not very robust (e.g. what happens if olsrd exits somewhere
in between - it could be a `kill -9` from the outside). Since OLSRD runs
on embedded hardware, no user action can be expected (let alone
enforced) so it must work fully automatically (at least in theory we
have o bugs in implementations;-).

And I assume that OLSRD doesn't announce that link during the test.

>  OLSR link only as a redundancy mechanism. Whereing if my DSL/Cable
> connection dies then I use my neighbors (who would be running olsr too
> of course) to reach the internet. 

	Bernd
-- 
Firmix Software GmbH                   http://www.firmix.at/
mobil: +43 664 4416156                 fax: +43 1 7890849-55
          Embedded Linux Development and Services



