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tech:network:tcp-ip:mtu-mss:mtu-mss

MTU/MSS Cheat Sheet

  1. MSS 1500 - 24 = 1476 (Ethernet + GRE)
  2. MSS 1500 - 8 = 1492 (PPPoE)
  3. MSS 1454 - 40 = 1414 (NTT NGN + PPPoE)
  4. MSS 1454 - 40 - 24 = 1390 (NTT NGN + PPPoE + GRE)
  5. MSS 1356 - 24 = 1332 (NTT NGN + PPPoE + IPsec(3des, md5-hamc)+ GRE)

NTT NGN + PPPoE

  • MTU 1454
  • MSS 1414

NTT NGN + PPPoE + IPsec(ESP, Tunnel mode)

  • MSS 1356
  • 1414 - 1356 = 58
    • = IP(20) + ESP Header(SPI 4 + Seq 4) + IV (8 (3des: Part of Payload Data)) + ESP Footer(8 (Padding 0 ~ 7 + Pad Length 1 + Next Header 1) + SHA1 12(Authentication Data))
    • = 20 + 4 + 4 + 8 + 8 + 12 = 56

Padding Must be times 8

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tech/network/tcp-ip/mtu-mss/mtu-mss.txt · Last modified: 2019/04/12 05:52 by wnoguchi