Layer 2 protocols – STP, VLANs, and security methods
Layer 2 is about connecting between directly attached nodes, and the protocol that implements the frames that carry the upper-layer IP packets is Ethernet. The devices transfer the frames and Layer 2 LAN switches. There are some additional mechanisms to improve, manage, and secure the information, for example, VLANs, port security, and more. Now, let's examine how it all runs together.
The Ethernet protocols
The Ethernet protocol was introduced in the early 1980s and was first standardized as IEEE 802.3 for 10 Mbps Ethernet. Later standards increased the bitrate to 100 Mbps, 1/10 Gbps, 25/40/100 Gbps, and in 2019, they increased to 200/400 Gbps. Additional mechanisms came along with link capacities; those that are related to information security will be discussed in the next sections.
The Ethernet frame structure
Ethernet frames come in three types: Ethernet-2, 802.3 with LLC encapsulation, and 802.3 with...
