> On 7 Nov 2018, at 04:10, Michael Rogers <michael@xxxxxxxxxxxxxxxx> wrote: > > On 06/11/2018 01:58, Roger Dingledine wrote: >> On Tue, Nov 06, 2018 at 11:38:33AM +1000, teor wrote: >>>> so if we could ask the guard for >>>> regular keepalives, we might be able to promise that the CPU will wake >>>> once every keepalive interval, unless the guard connection's lost, in >>>> which case it will wake once every 15 minutes. But keepalives from the >>>> guard would require a protocol change, which would take time to roll >>>> out, and would let the guard know (if it doesn't already) that the >>>> client's running on Android. >>> >>> Tor implemented netflow padding in 0.3.1.1-alpha (May 2017): >>> https://gitweb.torproject.org/torspec.git/tree/padding-spec.txt >>> >>> Connection padding may act like a keepalive, we should consider this >>> use case as we improve our padding designs. >> >> Relays already send a keepalive (padding) cell every 5 minutes: see >> the KeepalivePeriod config option. That's separate from any of the new >> netflow padding. Clients send them too. > > Ah, thanks! I didn't realise keepalives were sent from relays to clients > as well as vice versa. > > That gives us a max sleep of 5 minutes when a guard connection's open > and 15 minutes when it's not, which is a great improvement. > > Would it have much impact on the network to reduce the default keepalive > interval to, say, one minute? It's doable, but it would take a while to roll out to all relays. And it seems like a strange solution to a platform-specific problem. We might also have to be careful, because a multiple of the keepalive interval is used to close connections without any circuits. >> The netflow padding is more interesting for the Briar case, since it >> comes way way more often than keepalives: so if you're trying for deep >> sleep but you wake up for network activity every several seconds, you'll >> probably end up sad. > > Unfortunately we've disabled netflow padding due to bandwidth and > battery usage. Even with ReducedConnectionPadding? T
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