Re: [PATCH] bonding: send IPv6 neighbor advertisement on failover

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From: Vlad Yasevich
Date: Wednesday, October 8, 2008 - 12:53 pm

David Stevens wrote:

Nope, DAD doesn't trigger a cache update.


Well, the mac address is not new since the same address is replicated
across all slaves.  Also, unsolicited NAs are not permitted to change
the neighbor cache entries other then state.  An unsolicited NA will
cause an existing entry to go from REACHABLE to STALE, and nothing else.
So, it use in bonding is really the same as gratuitous ARP.


Yes, a dad counter could be re-used for this, but in some scenarios
it's overkill.  Frankly, NA itself is an overkill.  There may be
some unintentional consequences to using it that I am looking at now.


The problem is MLDs are only triggered when you are adding a new IPv6
multicast address.  However, in the bond failover case, we are simply
moving a hardware multicast address from one slave interface to
another while leaving the IPv6 multicast address on the master bond interface.
Thus there is not trigger to fire off an MLD report.

-vlad
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Re: [PATCH] bonding: send IPv6 neighbor advertisement on f ..., Vlad Yasevich, (Wed Oct 8, 12:53 pm)