On Thu, Jun 30, 2016 at 5:17 AM, Charles Swiger <[email protected]> wrote:
> [ ...top-posting reformated; please respect the mailing list > conventions... ] > > On Jun 29, 2016, at 3:20 PM, Franck Martin <[email protected]> wrote: > > On Jun 29, 2016, at 10:39, Charles Swiger <[email protected]> wrote: > >> Hi, Dan-- > >> > >> On Jun 28, 2016, at 8:52 PM, Dan Geist <[email protected]> wrote: > >>> Chuck, I don't disagree that overall experience may be better for > people with networks that don't have robust IPv6 capability, but there's > nothing magical about v4 (or v6 either) that makes it "perform better" at > layer 3. > >> > >> If you'd like to consider things at layer 3, note that IPv4 normally > has a 20-byte header size, and IPv6 has a 40-byte header. For large > packets, the difference in protocol overhead is not very significant-- > about 1%-- but for a 56-byte NTPv4 packet, using IPv6 means sending about > 125% as many bits over the wire as sending the same payload via IPv4. > >> > >> If other factors are held equal, IPv4 is always going to perform better > than IPv6 for NTP because smaller packets mean shorter transmit/receive > times and thus reduced latency for NTP polls. > >> > >> (There's nothing magical about protocol overhead, except perhaps > pretending that there isn't a difference. :-) > > > > Really? > > Yes, really. > > > http://ipv6bingo.com/ > https://blogs.akamai.com/2016/06/preparing-for-ipv6-only-mobile-networks-why-and-how.html > > > > The IPv6 packet header is fixed size, does not have checksum, the > routers do not fragment and ECN is more deployed on IPv6 than IPv4 and > there is not NAT,.. > > And what, pray tell, does any of that have to do with processing ~56 byte > UDP packets used by NTP? > If the only traffic is NTP, not much... > > For example, please collect some data about how often one sees IPv4 > packets with other than a 20-byte header size. People routinely use TCP > options, but IP protocol options are rarely used. > > > All that contributes to faster routing processing with less errors. > > I'd love to see you substantiate this claim. For example, show me max PPS > measurements and effective BER from a commercially available router > handling minimum size IPv4 versus IPv6 packets where IPv6 actually is > faster. > The Internet is a bit more complex than that, with congestion, weird links and paths, old hardware, etc... See the Akamai blog link above that reference several studies, where granted, many are for the moment observations. > > > Toute connaissance est une réponse à une question. > > While I am conversationally fluent in French, I don't think it would be > useful to the majority of the list readers to persue a multilingual > dialogue, n'est pas? > > Caught by my signature... _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
