On Dienstag 20 November 2007, rene wrote:
Hi,
Axel Neumann wrote:
There MUST be a different IP address for each BATMAN interface in the network (also if a single BATMAN node has more than one interface).
Is this implemented like this (where?)?
Yes it is implemented/designed like this. It operates on layer three and above. IP addresses are used to differentiate between different links to the same neighbors. For example two nodes A and B, each with two wireless interfaces 1 and 2. All interfaces operating in the same channel, bssid, ... How could node A differentiate between the link A1<->B1 and A1<->B2 if it is not aware of any MAC addresses. But even if it is aware of MAC addresses. How could it set up the routing table to ensure that a packet to a distant node C should be routed via B1 (and NOT via B2)?
just by setting the interface to the way the package has to leave the node? Just the same way olsr does, I'm not a protocol designer but don't see any main reason why Batman shouldn't be possible to do it similar.
IMO that does only work if the interfaces of a node are NOT connected to the same physical/logical link (e.g. B1 and B2 are operating on different channels or with different cell IDs,...). Otherwise specifying the outgoing interface is not enough. Even if node A has only one interface (A1). If there is a link A1<->B1 and a link A1<->B2 the problem remains:
How could it set up the routing table to ensure that a packet to a distant node C should be routed via B1 (and NOT via B2)?
The outgoing interface of node A is A1, for both cases. Setting the outgoing interface to A1 has no effect.
Maybe there is a way to configure the next-hop-mac address instead of the next-hop-ip address. But then you rather have layer 2 routing and not layer 3.
/axel
Actually, I did not even know that this is possible - is such a configuration proposed somewhere. I can imagine that this somehow works but how shure are you that this does not introduce any negative side effects?
We are using this in Rostock since a while (on all WRAPs and on selected APs) and it works very well. Side effects? Maybe, you never know for sure, none recognized and I'm not deep enough into protocol designs to answer this from a theoretical point of view. But it's a great feature which makes Mesh networking much easier and the whole structure much cleaner.
Regards, Rene
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