The Layer 2 Ethernet frame as described here includes Ethernet headers, i.e. the CRC, but not the Inter Frame Gap, Preamble, or Start of Frame Delimiter (SFD).
The maximum frame size depends on the interface MTU (Maximum Transmission Unit); the default value is 1500 bytes.
The minimum frame size for IPv4 is 64 bytes, where the Ethernet header takes up 18 bytes [1], the IPv4 header 20 bytes, and the UDP header 8 bytes. The remaining 18 bytes are payload, where Netrounds places a sequence number, a timestamp, a checksum, and a stream ID.
- Minimum IPv4 frame size = 18 (Ethernet) + 20 (IPv4) + 8 (UDP) + 18 (payload) = 64 bytes
For IPv6 the minimum frame size is 84 bytes, since the IPv6 header is 40 bytes long.
- Minimum IPv6 frame size = 18 (Ethernet) + 40 (IPv6) + 8 (UDP) + 18 (payload) = 84 bytes
[1] In the original ethernet specification, 64 bytes would fill the cable from end-to-end, allowing collisions to be detected by all hosts. The original ethernet standard also specified 14 bytes for the header, and 4 bytes for the frame check sequence. That is 18 bytes. subtract 18 from 64, and you get 46 as the minimum payload. Since then, you can add a four byte VLAN tag. So, with the VLAN tag, the minimum payload size is 42. Without the VLAN tag, the minimum payload size remains 46.