[Olsr-users] What is the difference between dyn_gw and dyn_gw_plain

Eric Malkowski (spam-protected)
Mon Apr 7 15:27:11 CEST 2014

I have always liked dyn_gw_plain because it allows me to choose whatever 
method I want to decide if the local gateway in a node is "good" or not.
I setup 2 routing tables (main + table 100 or something) in the linux 
kernel on my setup and then direct my ping requests to multiple internet 
sites I know should be working if the local internet link is good.  The 
pings use a source IP such that they go out the 2nd routing table so 
they will hit the local internet connection whether there is a default 
route in the main table or not -- i.e. the extra table 100 has a default 
route always pointing to the local internet connection gateway. 

If I get a response from any of the 5 internet sites I ping, I assume 
the link is good and install a default route in the main linux routing 
table.  OLSR will notice this and then advertise the local default route 
to nodes in the mesh.  If all 5 sites I ping fail to respond (I have a 
script that does this in about 15 seconds or so) I remove the default 
route from the main table and it allows the node to have it's normal 
traffic go out some other gateway from some other node in the network 
that has an internet connection.

Allows for many internet connections.  Only problem is if an active 
connection through NAT on the local node goes down and node switches 
gateways, session will have to restart.  I don't find that a big deal.

I like being able to choose multiple things to ping and possible look at 
local link hardware status to decide if a local internet connection is 
good or not.  Just being able to ping next hop gateway on your ISP 
connection doesn't imply the internet is working !!!

I haven't messed with some of the newer features like smart gateway -- 
not sure I totally understand it, but one of these days I will update 
and try some of the new stuff the latest OLSR provides.  Not sure if the 
latest version of OLSR with dyn_gw_plain will still work the way I 
describe above... but it probably does.

Best of luck

-Eric Malkowski

> Message: 4
> Date: Mon, 7 Apr 2014 09:24:21 +0200
> From: Saverio Proto <(spam-protected)>
> To: ANDERSON JUNIOR GADO DA SILVA <(spam-protected)>
> Cc: olsr ysers mailing list <(spam-protected)>
> Subject: Re: [Olsr-users] What is the difference between dyn_gw and
> 	dyn_gw_plain?
> Message-ID:
> 	<(spam-protected)>
> Content-Type: text/plain; charset=UTF-8
> use dyn_gw
> I think the plain plugin was implemented because in the past
> libpthread had some issue with OpenWrt on the broadcom target.
> so a libpthread free Olsrd was needed.
> Saverio

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