Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp-primingexchange-00.txt
Declan Ma <madi@zdns.cn> Fri, 28 November 2014 07:35 UTC
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From: Declan Ma <madi@zdns.cn>
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Date: Fri, 28 Nov 2014 15:35:15 +0800
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To: Paul Vixie <paul@redbarn.org>
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Cc: Davey Song <songlinjian@gmail.com>, dnsop@ietf.org
Subject: Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp-primingexchange-00.txt
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Paul, I go along with the “optimal number of root name servers”. Besides, the distribution of root zone file among the servers with a pleasing latency therefore bears importance. Truly an interesting topic for the testbed by ZDNS and BII. Declan Ma ZDNS Ltd. > 在 2014年11月28日,下午3:21,Paul Vixie <paul@redbarn.org> 写道: > > > > Davey Song wrote: >> I try to express the idea: is there any possibility that if we can >> breaks the rareness of Root servers. The arguments and disputes will >> cease accordingly. Actually this idea is out of the scope of this draft. > > i think there is an interesting research question here: how many root > name servers is too many, and what are the limitations, and what is the > optimal number of root name servers? > > for example, if 13 is good, would 130 (10X) or 1300 (100X) be better? > even with 1300 root name servers, the fallback to TCP after TC=1 in a > priming query (even with EDNS) would only add one extra round trip over > the three that are required to run a TCP query. since priming queries > are uncommon, i still don't see why that first round trip is worth avoiding. > > RDNS servers who perform round trip measurements to each potential name > server for each zone cut would have a lot more state to maintain, but > that state would not be large by today's standards (DNSSEC signatures > have bloated RDNS memory footprints far more, without concern.) > > however, the systemic complexity of all those RDNS servers performing > all those measurements seems like cause for concern. with 1300 root name > servers, it would take 1300 referrals for any given RDNS server to learn > which root name server was closest to it. unless all 1300 of those > servers are widely anycast, then many of those initial 1300 referrals > would have suboptimal round trip times. also with that many servers, > error theory predicts that some number of them will be unreachable, > causing retries that add to the total number of referral events required > to locate the closest (by RTT) root server. > > if 1300 is obviously too many, why? what's the optimal number of root > name servers for an RDNS population estimated to be about 40M? does the > optimal number change when some share of root name servers are widely > anycasted? > > i share these research questions for four reasons. > > first, ZDNS and BII are ideally suited to investigate this matter in > your test bed. > > second, there is no evidence at present that "13" is too many or too few > root servers. > > third, this line of thinking is what led to my ICANN ITI proposal > involving only two root name server identities, each of which being > massively and hierarchically anycasted. > > fourth, because without an answer to these research questions, it's > impossible to evaluate the cost and complexity tradeoff against > increased internet resilience from pursuing your "tcp-primingexchange" > proposal. > > -- > Paul Vixie > > _______________________________________________ > DNSOP mailing list > DNSOP@ietf.org > https://www.ietf.org/mailman/listinfo/dnsop
- [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp-pri… Davey Song
- Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp… Paul Vixie
- Re: [DNSOP] I-D Action: draft-song-dnsop-tcp-prim… Paul Hoffman
- Re: [DNSOP] I-D Action: draft-song-dnsop-tcp-prim… Mark Andrews
- Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp… Davey Song
- Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp… Paul Vixie
- Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp… Declan Ma
- Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp… Davey Song
- Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp… Paul Vixie
- Re: [DNSOP] I-D Action: draft-song-dnsop-tcp-prim… Davey Song
- Re: [DNSOP] I-D Action: draft-song-dnsop-tcp-prim… Davey Song
- Re: [DNSOP] I-D Action: draft-song-dnsop-tcp-prim… Paul Hoffman
- Re: [DNSOP] I-D Action: draft-song-dnsop-tcp-prim… Davey Song
- Re: [DNSOP] I-D Action: draft-song-dnsop-tcp-prim… Davey Song
- Re: [DNSOP] Fwd: I-D Action: draft-song-dnsop-tcp… Guangqing Deng