Ethernet payload datarates

TCP over Ethernet:

• Assuming no header compression (e.g. not PPP)
• Add 20 Bytes IPv4 header or 40 Bytes IPv6 header (no options)
• Add 20 Bytes TCP header
• Add 12 Bytes optional TCP timestamps
• Max TCP Payload data rates over ethernet are thus:
  • (1500-40)/(38+1500) = 94.9285 % IPv4, minimal headers
  • (1500-52)/(38+1500) = 94.1482 % IPv4, TCP timestamps
  • (1500-52)/(42+1500) = 93.9040 % 802.1q, IPv4, TCP timestamps
  • (1500-60)/(38+1500) = 93.6281 % IPv6, minimal headers
  • (1500-72)/(38+1500) = 92.8479 % IPv6, TCP timestamps
  • (1500-72)/(42+1500) = 92.6070 % 802.1q, IPv6, ICP timestamps

UDP over Ethernet:

• Add 20 Bytes IPv4 header or 40 Bytes IPv6 header (no options)
• Add 8 Bytes UDP header
• Max UDP Payload data rates over ethernet are thus:
  • (1500-28)/(38+1500) = 95.7087 % IPv4
  • (1500-28)/(42+1500) = 95.4604 % 802.1q, IPv4
  • (1500-48)/(38+1500) = 94.4083 % IPv6
  • (1500-48)/(42+1500) = 94.1634 % 802.1q, IPv6

N.B. 802.1q describes ethernet traffic behind a router, or in a Vlan. (Wikipedia)

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