Examples of deterministic protocols include Token Ring and FDDI. In a Token Ring network, individual hosts are arranged in a ring and a special data token travels around the ring to each host in sequence. When a host wants to transmit, it seizes the token, transmits the data for a limited time, and then forwards the token to the next host in the ring. Token Ring is a collisionless environment as only one host is able to transmit at any given time.

Non-deterministic MAC protocols use a first-come, first-served approach. CSMA/CD is a simple system. The NIC listens for an absence of a signal on the media and starts transmitting. If two nodes transmit at the same time a collision occurs and none of the nodes are able to transmit.

Three common Layer 2 technologies are Token Ring, FDDI, and Ethernet. All three specify Layer 2 issues, LLC, naming, framing, and MAC, as well as Layer 1 signaling components and media issues. The specific technologies for each are as follows:

• Ethernet – logical bus topology (information flow is on a linear bus) and physical star or extended star (wired as a star)
• Token Ring – logical ring topology (in other words, information flow is controlled in a ring) and a physical star topology (in other words, it is wired as a star)
• FDDI – logical ring topology (information flow is controlled in a ring) and physical dual-ring topology (wired as a dual-ring)

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