Reject it? Why would I do that? I'm just makeing sure of stuff before I decide what to do. Besides, sometimes it is better to learn a little bit before I just blindly follow the advice of the old school ;^)
> I would have guessed even 802.11a or g AP would be able to reach a couple thousand packets per second, which could result in sub-millisecond packet timing, and 802.11n AP perhaps few hundred thousand packets per second resulting in a few microseconds packet timing? Soooo, at 54Mbps sending a 1500 byte packet would take 1500 * 8 / 54M which gives me 0.2222 milliseconds per packet. Hmmmm, perhaps there is an argument for a PPS source here. If we are off by 1 ms then we could lose 4 or 5 packets to clock skew. > ...but latency? On my control plane? No way ;^) That lan is soooo > lightly loaded that any packet can get sent anywhere it wants at any > time on Gigabit ethernet. > With Gigabit you may get erratic latency due to buffering and interrupt > coalescing. Just what do you mean by erratic? This is a modern networking device, it's going send the packet right away. Sure a few interrupts will coalese but it's not gonna get recieve livelock or anything like that. The GigE card is gonna get the packet out the door right away, I think any jitter will be small. --- On Fri, 9/17/10, John Hasler <[email protected]> wrote: > From: John Hasler <[email protected]> > Subject: Re: [ntp:questions] Why does ntp keep changing my conf file? > To: [email protected] > Date: Friday, September 17, 2010, 5:33 PM > Daniel Havey writes: > > ...but latency? On my control plane? No > way ;^) That lan is soooo > > lightly loaded that any packet can get sent anywhere > it wants at any > > time on Gigabit ethernet. > > With Gigabit you may get erratic latency due to buffering > and interrupt > coalescing. > > > That might be a little extreme, we don't have a PPS > source, or roof > > access for a GPS receiver. > > Since all you want is synchronization among your machines > your PPS could > free run. You should be able to build one. It's > trivial: just a stable > one Hertz pulse generator. > > > If we can get down to a millisecond then we are > golden. > > Then you don't need a PPS source. > -- > John Hasler > [email protected] > Dancing Horse Hill > Elmwood, WI USA > > _______________________________________________ > questions mailing list > [email protected] > http://lists.ntp.org/listinfo/questions > _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
