[Babel-users] cornercase issue (link sensing)

Juliusz Chroboczek Juliusz.Chroboczek at pps.jussieu.fr
Wed Apr 29 16:44:15 UTC 2009

Hi Harald,

> I believe I found an issue that might lead to unstable links in the
> corner case of two interfaces sharing the same broadcast domain:
> Since hellos on different interfaces are sent with different
> sequence numbers peer nodes might get very confused.

Babel version 1 had this problem, which is the main reason for the
incompatible version 2 protocol.  In version 2, the neighbour is
identified with the link-local IPv6 address, so multiple adjacencies
between the same two nodes are okay.

> - Especially vlan setups often use the same mac address on many
> interfaces.

If there's a MAC address collision in a single broadcast domain,
duplicate address detection at the IPv6 layer should disable one of the
two interfaces.  (Or both, if there's a race condition.)

> BTW: Just noticed, that the config file parser is very unhappy about
> lines with trailing white space.

Thanks for the report, I'll look into it.


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