[OLSR-users] When does a node use ARP?
Sat Jul 8 22:47:46 CEST 2006
On Sun, 2006-07-09 at 01:16 +1000, Dan Flett wrote:
> I am wondering - can an OLSR node communicate with a one-hop non-OLSR node
> if there is a HNA present with a netmask that overlaps the non-OLSR node?
Yes, and no HNA is needed if communication is needed when the boxes can
I have a WLAN-ip-camera setup with a a.b.c.d/24 address connecting to
one of my nodes at a.b.c.1/16 olsr-network.
If I nedd to be able to contact the camera from elsewhere the camrea
need to be setup with standard gateway to a.b.c.1 _and_ a HNA entry to
a.b.c.d, otherwise the will be do routes to/from the camera.
> Consider this scenario:
> Node A has a wireless interface with the IP address 10.10.0.1/16 and is
> running OLSR
> Node Z is running OLSR and is injecting a HNA of 10.10.0.0/17 onto the
> network and is many hops away from Node A
> Node B is has a wireless interface with the IP address of 10.10.0.2/16 and
> is within radio range (and therefore Ethernet range), of Node A but does not
> run OLSR.
> My question is - If Node A, with an empty ARP cache, attempts to communicate
> with Node B - what happens? Normally Node A would send an ARP broadcast and
> Node B would answer it. But does the /17 HNA from Node Z interfere with
> this? Would Node A consult it's routing table and decide that the traffic
> should go via Node Z, unaware that Node B is within direct Ethernet range?
If there is a route to some IP no arp-request will be sent, as
(logically) the route is already known.
Mixing olsr-nodes and non-olsr-nodes is a real mess.
Especially if the non-olsr-node is expected to do some routing. Again it
can be done by using static routes on (all) the neightbourghs, but it
defeats the automatic route-creation done but olsr.
In my world, I'd only allow end-nodes to be non-olsr, as in my setup
with the camera mentioned above. Under no circumstances would I use
non-olsr-nodes as routers.
I'd doing some experiments with openvpn to connect olsr-islands
together vis open vpn, but all nodes will still be logically routed on
the same 10.128.x.y/16 network. Some WLAN, some ethernet and som
Henning Wangerin <(spam-protected)>
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