A Comparison of Existing Ethernet Frame Specifications
  The Ethernet as we see it today is a result of many stages of evolution. As a result, the Ethernet frame format at the link layer also has seen many changes. One might expect a consistent format of link layer frames as we usually study in text books, in actual practice this is not the case. Please refer to the manuscript for complete abstract. 
Muhammad Farooq-i-Azam
cs.NI