[Olsr-dev] Seeking comments: OLSR+ETX v/s DSR+ETX

Juliusz Chroboczek (spam-protected)
Mon Dec 24 00:09:42 CET 2007


> start olsrd.  That's fine. It still takes about ~40 seconds until the gateway 
> has a route back to me (4 hops).
>
> We use a Hello interval of 5 seconds here, so if X>6 this would be an 
> additional delay of >30 secs. 

Hmm... in Babel, I use triggered updates to avoid this delay: when
a new route appears, it is immediately advertised to all neighbours,
even if the periodic update is not scheduled yet.

As far as I can tell, there's nothing preventing scheduled link
database updates from being used in a link-state protocol -- in fact,
OSPF does incremental updates that way.

I haven't looked at the OLSR spec recently, so I'm not quite sure if
it is possible to send a partial link database update -- just add
a new link to the database.  If it isn't, there's nothing preventing
the -NG project from defining a new « TC-delta » packet.

(In Babel, I also use irregular hello intervals to speed-up the link
quality convergence when a new neighbour appears, but I believe that's
not applicable to OLSR without some pretty heavy surgery to the protocol.)

Regards,

                                        Juliusz




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