Paper Review:
Ethernet: Distributed Packet Switching for Local Computer Networks

Reviewer: Robert Dugas


This paper deals with the problem of how to design an effective data link layer for local area networks.


The contribution can be gleaned from the title, namely the development of the ethernet (and with it associated algorithms and protocols) so pervasive today.

Main Ideas

  • An ethernet proves to be an effective means of local area network communication.
  • Carrier signal detection combined with backoff algorithms can provide sufficient congestion control
  • It is suffices to provide best-effort service at the data link layer and allow hosts to perform end-to-end checking a higher layers.


    This paper paved the way for the widespread deployment of ethernet networks throughout the world

    The methodology is both illustrative and convincing. Rather than relying on simulations, the authors actually constructed a ethernet operating at 3 MB/ Sec and laid 1 km of cable. This platform allowed thorough testing to be performed.

    Some limiting issues are discussed by the authors themselves such as inadaquate address field length in the headers. Another issue hinted at is the limitation on packet size. Once packet sizes increase to approximate that of a slot, performance drops to the 1/e asymptotic behavior encountered in less optomized networks.

    A chief lesson of this paper is that a 256 node ethernet can be constructed to operate at around 95% efficiency at 3 MB. For 1976, this result had to be extremely impressive. Another important lesson is that binary exponential backoff can provide adaquate node cooperation in a local area network.