This 2-octet field holds a user-defined Ethernet EtherType value, indexed by etsysESwitchEtherTypeIndex, for use as a protocol filter reference elsewhere in the switch's protocol table. Admins create rows here when they need to filter or classify traffic by a nonstandard EtherType that isn't one of the switch's predefined protocol types, then reference this row's index from a userEtherType protocol entry. An admin could set etsysESwitchEtherTypeValue to the two octets 0x88 0xB5 to register a custom EtherType, then use it as the basis for a protocol-based VLAN classification rule.