IPv6 Path MTU in the World and Japan

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͖͔͚ͬ͸ JANOG33.5

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*1W1BUI.56  ʹ͍ͭͯܰ͘

.56 1500 Host ϗετ͕ૹग़Ͱ͖Δ  ύέοτͷ࠷େ௕ (Maximum Transfer Unit)

.56஋͸ճઢ࣍ୈ 1500 H Ethernet 1500 H WiFi 1454 H NGN 
PPPoE 1500 H NGN  IPoE 1280 H 6to4 1436 H IPsec  VPN 1500 H LTE 1420 H ?

1BUI.56 ௨৴૬खͱͷؒͷ .56ͷ࠷খ஋ R R R 1500 1454 1280 1436
C S S C 1280 1280 1280 1280 R R R

1BUI.56%JTDPWFSZ 1BUI.56Λ  ݟ͚ͭΔಈ࡞ R R R 1500 1454 1280 1436
C S

3way handshake data (size=100) data (size=200) (size=1436) data x data
(size=1280) data (size=216) R R R 1500 1454 1280 1436 C S ICMPv6 Packet Too Big $ͷ1.56 ͸Ͷ

1BUI.56#MBDL)PMF 1BUI.56%JTDPWFSZʹࣦഊ͠ɺ 1BUI.56ΑΓେ͖ͳύέοτΛ  ૹΔ͜ͱͰύέϩε͕ൃੜ͢Δݱ৅ R R R 1500 ??? ???
1436 C S ?

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C S 3way handshake Maximum Segment Size .44͸  Ͱ .44͸  Ͱ Clamp! $΁͸  Ͱ

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ճઢछྨ .56ͷࣾ಺-"/ .56ͷ/55ޫωΫετ111P&઀ଓ .56ͷ1BUI.56#MBDL)PMF͖ͭ *1*1τϯωϧ઀ଓ

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World IPv6 Launch

ੈքͷαΠτ Top 100

೔ຊͷαΠτ 94

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World 72 / 72 .56؀ڥͰ͸੒ޭ Japan 72 / 72

World Japan 72 / 72 ※ؾʹͳΔ1ͭ͸ϩγΞͷಈըڞ༗αΠτ .56؀ڥͰ΋੒ޭ 71 / 72
1

World 63 9 յ໓ɻɻɻ Japan 61 11 #MBDL)PMF؀ڥͰ͸

5$1.44 $MBNQJOH  ౤ೖʂ

World 72 / 72 #MBDL)PMF؀ڥ͕ʹʂ Japan 72 / 72

World 72 / 72 .56؀ڥ΋΋ͪΖΜ Japan 72 / 72

ίϯςϯπऔಘ੒ޭ World Japan MTU1500 72 72 MTU1454 71 72 MTU1454
/ TCPMSS 72 72 MTU1400  PMTU black hole 9 11 MTU1400 / TCPMSS  PMTU black hole 72 72

ৄ͘͠ݟΔ ͦͷ5$1σʔλ௕ ϖΠϩʔυ௕

5$1σʔλ௕ͷ෼෍.56 Sites 0 25 50 75 100 TCP Segment Size
(Max) 11721208122012281340134813541360136213681380138213881394140814281440 World Japan 9+10 PMTU black  hole ରԠ? ࠷େαΠζ 52+56

(Max) 11721208122012281340134813541360136213681380138213881394140814281440 World Japan 52+56 9+10

(Max) 11721208122012281340134813541360136213681380138213881394140814281440 World Japan 41+52 9+10

5$1σʔλ௕ͷ෼෍5$1.44 Sites 0 25 50 75 100 TCP Segment Size
(Max) 11721208122012281340134813541360136213681380138213881394140814281440 World Japan 51+57 9+11

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ৄ͘͠ݟΔ ͦͷ5$1ͷ࠶ૹൃੜ ͷՄೳੑ

5$1࠶ૹͷ༗ແ ࠶ૹ͋Γ ࠶ૹͳ͠ MTU1500 World 0 72 Japan 2 70
MTU1454 World 25 47 Japan 37 35 MTU1454 TCPMSS World 0 72 Japan 2 70

w .56͕ΑΓখ͍͞ͱ࠶ૹ͕ൃੜ͢ΔՄೳੑ ͕͋Δ 1BUI.56%JTDPWFSZͷͨΊ w 5$1.44$MBNQJOHΛೖΕΔͱ࠶ૹ͕ແ͘ͳΓ  εϧʔϓοτͷ޲্͕๬ΊΔ 5$1࠶ૹͷ༗ແ ͔ΒΘ͔ͬͨ͜ͱ

ௐࠪͰಘΒΕͨڭ܇

• MTU1500 ͷճઢΛҾ͘ • ICMP6 Packet Too Big ΛϑΟϧλ͠ͳ͍ •
ϧʔλʹ TCP MSS Clamping ΛೖΕ͓ͯ͘ ΫϥΠΞϯτ

• MTU ͕ 1500 ΑΓখ͞ͳϦϯΫΛ࡞Βͳ͍ • ICMP6 Packet Too Big
ΛϑΟϧλ͠ͳ͍ *41

• (҆શΛظ͢ͳΒ) MTU Λ 1280 ʹߜ͓ͬͯ͘ • ্ྲྀʹ MTU<1500 ͳϦϯΫ͕͋Δ৔߹͸
MTU Λ ߜΔ͔ TCP MSS Clamping Λ࣮ࢪ͢Δ αʔό

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࣭໰͸͋Γ·ͤΜ͔ ࠤݪ ۩޾ <[email protected]> גࣜձࣾΠϯλʔωοτΠχγΞςΟϒ *1W1BUI.56ͷ܏޲ͱରࡦ ʙ.56͕খͯ͘͞Կ͕ѱ͍ʂʁʙ https://speakerdeck.com/tsahara/ ipv6-path-mtu-in-the-world-and-japan

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1/1 1/2 1/3 1/4 11/1 2/1 2/2 3/1 3/2 3/3 5/1 World Japan

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IPv6 Path MTU in the World and Japan

IPv6 Path MTU in the World and Japan

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