[Olsr-dev] Announce HNA 0.0.0.0/0, but also receive next 0.0.0.0/0

[Clemens Hopfer]

On Friday 29 October 2010 08:51:04 Bastian Bittorf wrote:
> [...]
> We want to announce 0/0 on every node, that is connected
> to the backbone. (but has no own internet-connectivity,
> only through OLSR/mesh)

Hi,

be careful with setups like this, it is extremely easy to create persistent 
routing loops.

For example:
You got 3 backbone nodes in the following topology:
A-B-C
Only A has got internet connection, but every node announces 0/0.
For node B there is no way to know if A or C got internet connection, if it 
selects C as gateway, you got a persistent loop between B and C.

If you want to do things like this, there is almost no other way than running 
another routing protocol (OSPF, OLSR or whatever..) on the backbone nodes.

If you don't want to do this another approach would be to write a plugin, that 
floods the "real" HNA connectivity across the network and every backbone node 
calculates the path to the nearest gateway based on this information.
But if you got a node on your path to 0/0, that selects you as Gateway 
(because of your HNA) you got a loop again...


Regards,
Clemens
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.olsr.org/pipermail/olsr-dev/attachments/20101029/c1fc8421/attachment.sig>