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Ethernet is an example of a layer 2 protocol and is the most commonly used layer 2 protocol today. A basic understanding of some of the characteristics of Ethernet is useful in the context of infrastructure edge computing, as the protocol is so widely used both within the infrastructure edge data centre, as well as between them and between other facilities of both similar and larger scale.

Ethernet uses broadcast communication to perform network endpoint discovery. This means that when an Ethernet endpoint receives a frame with a destination MAC address and the endpoint does not have an existing entry in its switching table for that destination MAC address, a request is sent to all other Ethernet endpoints on that segment of the network, asking for the location of the endpoint which has that destination MAC address assigned to one of its interfaces. The protocol was designed in this way for implementation simplicity and low cost, both of which have helped Ethernet become established as the dominant layer 2 protocol today; but there is an equal drawback in regard to the inefficiency of this behaviour in a larger network, where the volume of broadcast traffic can be substantial enough to impact the performance of network endpoints and ultimately of the network.

The protocol is capable of supporting frame sizes between 64 and 1518 bytes as standard, and some equipment can be configured to support so‐called jumbo frames of up to 9600 bytes. The latter are useful for some use cases which rely on these jumbo frames in order to lower the overhead of large numbers of Ethernet frame headers involved when carrying data, or for protocols such as those of storage area networks (SANs), which natively use data segmentation sizes closer to a jumbo frame.

The most common type of traffic encountered on a modern network today is an Ethernet frame that encapsulates an Internet Protocol version 4 (IPv4) or Internet Protocol version 6 (IPv6) packet, using TCP or UDP as its transport layer protocol, carrying some application data from a source endpoint to its destination endpoint. This combination of protocols is used for a wide range of use cases and across almost every scale of network in common use today.