[Olsr-users] Routing problems with multiple interfaces

David Murray (spam-protected)
Thu Jan 17 10:31:34 CET 2008


I am getting a few routing problems in my experimental network. I have 
four nodes each equipped with two wireless cards. Each node has two 
links (see diagram). These links are A-C, A-D , B-D and B-C (see 
diagram) and each link is running on a different frequency. The 
frequencies discovered are dynamically found which means that upon boot 
time, there is the potential for ath0 on node D to be initially 
connected to node A but then later switched to connect with node B.

The network appears to work, routing tables get filled and look 
perfectly sane et cetera. However, there is a problem that certain 
nodes cannot ping other nodes. To try to understand the problems I have 
written scripts to take snapshots of the routing table and 
simultaneously record ping results.

- Node A can ping one interface on C and one interface on node D and 
nothing on B
- Node B can ping every interface on node C and D but cannot ping any 
interface on node A
-Node C can ping every interface on A and B but cannot ping any 
interface on  node D
- Node C can ping every interface.


A            B
| \        / |
|   \    /   |
|     \/     |
|    /  \    |
|  /      \  |
|/          \|
C            D

I am a little confused by this problem as the routing tables look fine 
and the routing protocol seems to be exchanging packets fine however 
there are problems with pings. I am thinking that this could be an arp 
issue but when I look at the arp table, each node looks consistently 
the same each with only one arp entry for each wireless interface.

Does anyone have any suggestions at to where the problem might lie or 
how I could further define the problem? has anyone else has much 
experience with olsr and two wireless cards?

Thank you for your time


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