[OLSR-users] OLSR Linux Network newbie questions

Benjamin Watson (spam-protected)
Thu Oct 26 03:51:20 CEST 2006


Hello List,

I'm a first time poster and, quite frankly, new to OLSR and Linux
networking, please forgive my long-winded post!!

I'm working on a wireless mesh networking project and have run into
some road blocks.
I'm sure I'm "almost there" and overlooking something trivial, so I
thought I'd get some insight from the list.

What I'm attempting to do is set up the following scenario:

Laptop 1 <--link A--> MeshRouterA <--OLSR link B--> MeshRouterB
<--Link C--> Laptop 2

The Mesh routers are Metrix Mark II kits with 2 wireless radios and an
ethernet port running Pyramid Linux with olsrd available.

Link A is an 802.11b link where Laptop 1 is in client mode and one of
MeshRouterA's radios is an access point serving DHCP.
Link B is an 802.11a link where one radio on each MeshRouter has the
same channel, essid, and is set to ad-hoc mode.
Link C is similar to link A, only between MeshRouterB and Laptop 2.

I've decided to use the 10.0.0.0/8 ip range for expandibility and
flexibility down the road for more nodes.

I've assigned the LinkA radio on MeshRouterA (wlan0) the following:
IP: 10.128.1.2
Mask: 255.255.255.0
Broadcast: 10.128.1.255

Laptop1 connects to MeshRouterA and is assigned:
IP: 10.128.1.79
Mask: 255.255.255.0
Gateway: 10.128.1.2

Similarly, for the LinkC radio on MeshRouterB (wlan0) the following:
IP: 10.128.2.2
Mask: 255.255.255.0
Broadcast: 10.128.2.255

Laptop2 conneect to MeshRouterB and is assigned:
IP: 10.128.2.175
Mask: 255.255.255.0
Gateway: 10.128.2.2

This is all wonderful, the laptops can connect to the APs, can SSH
into them, etc.

For Link B, the MeshRouterA radio (ath0) gets:
IP: 10.128.1.1
Mask: 255.255.0.0
Broadcast: 10.128.255.255

And the MeshRouterB radio (ath0) gets:
IP: 10.128.2.1
Mask: 255.255.0.0
Broadcast: 10.128.255.255

The MeshRouters are successfully exchanging OLSR messages and I can
see the nodes "linked" in a visualization graph.

Furthermore, MeshRouterA can ping Laptop 1, and all of the interfaces
on MeshRouterB, but cannot reach Laptop 2.
Likewise, MeshRouterA can ping Laptop 2, and all of the interfaces on
MeshRouterA., but cannot reach Laptop 1.

The Laptops can obviously ping the MeshRouters they're connected to,
but not the "other" MeshRouter or the "other" laptop.

I enabled OLSR on all interfaces for both MeshRouters and let
MeshRouterA do an HNA announcement of 0.0.0.0 0.0.0.0 as it is
connected to "the Internet" on eth0.

The routing table on MeshRouterA looks like:
Destination  Gateway     Mask                   Iface
10.128.2.1       *            255.255.255.255   ath0
10.128.2.2   10.128.2.1  255.255.255.255   ath0
10.128.1.0       *            255.255.255.0       wlan0
192.168.0.0     *            255.255.255.0       eth0
10.128.0.0       *            255.255.0.0          ath0
default        192.168.0.1 0.0.0.0                 eth0

The routing table on MeshRouterB is "similar".

I know OLSR doesn't actually route packets, but aids in setting up the
routing tables and so long as port forwarding is enabled (and it is),
packets should be routed according to the table.

However, I'm not getting the Laptop-to-Laptop communication I desire.

Any suggestions?

Thanks for tolerating my long post!!

Ben




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