Currently, the value used for Ethertype in jumbo frames is not clear. The draft authors also responded to the chair's letter, but no subsequent answer from the IEEE 802.3 has been recorded. The chair of IEEE 802.3 at the time, Geoff Thompson, responded to the draft outlining IEEE 802.3's official position and the reasons behind the position. However, the proposition was not accepted and it is defunct. The proposition to resolve this conflict was to substitute the special EtherType 0x8870 when a length would otherwise be used.

The size of the payload of non-standard jumbo frames, typically ~9000 Bytes long, falls within the range used by EtherType, creating a conflict. The interpretation of values 1501–1535, inclusive, is undefined. Thus, values of 1500 (0x05DC) and below for this field indicate that the field is used as the size of the payload of the Ethernet Frame while values of 1536 and above indicate that the field is used to represent EtherType. That value was chosen because the maximum length (MTU) of the data field of an Ethernet 802.3 frame was 1500 bytes (0x05DC). In order to allow packets using Ethernet v2 framing and packets using the IEEE 802.3 framing to be used on the same Ethernet segment, a unifying standard (IEEE 802.3x-1997) was introduced that required that EtherType values be greater than or equal to 1536 (0x0600). Ethernet v2 framing considered these octets to represent EtherType while the original IEEE 802.3 framing considered these octets to represent the size of the payload in bytes. Historically, depending on the type of Ethernet framing that was in use on an Ethernet segment, both interpretations were simultaneously valid, leading to ambiguity. In modern implementations of Ethernet, the field within the Ethernet frame used to describe the EtherType also can be used to represent the size of the payload of the Ethernet Frame. OverviewĮtherType numbering generally starts from 0x0800. This field was first defined by the Ethernet II framing networking standard, and later adapted for the IEEE 802.3 Ethernet networking standard. It is used to indicate which protocol is encapsulated in the payload of an Ethernet Frame. EtherType is a two- octet field in an Ethernet frame.

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