Paul Jakma wrote:
Just not sending RAs (or not including the affected prefix in RAs) would achieve same effect though wouldn't it?
I'm just curious what would be wrong with a setup like:
- valid lifetime: very high (say weeks) - preferred: low, eg 10s or 15s - RA interval: very low, 5s or so.
If link goes down, just stop sending RAs/including prefix in RAs. In 15s hosts start preferring other prefixes. For datagramme protocols with no kernel flow state (eg, potentially, shim6), the next packet after preferred times out would use a new source address.
The behavior we'd want in multihoming is instead The address prefix has failed (at least for external communication). If there is a mechanism (like shim6) which can be used to quickly failover to some other address, then it makes sense to invoke it. Also, new communication which picks a source address should avoid using the failed prefix. But for existing communication when there isn't an easy way to switch to another address, it isn't clear what to do. (In some cases it might make sense to reset the ULP connection and recreating it, which will make it get a non-failed source address, but in other cases it would be better to wait for the failed address to start working again.)
Erik