[ ...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? 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. > 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? Regards, -- -Chuck _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
