Understanding and preparing for network threats is important, and hardening Layer 2 is becoming imperative. Cisco switches offer a wide range of security features at Layer 2 to protect the network traffic flow and the devices themselves. Applying first-class security measures to the upper layers (Layers 3 and higher) does not benefit your network if Layer 2 is compromised. Network security is only as strong as the weakest link, and Layer 2 is no exception. The data-link layer (Layer 2 of the OSI model) provides the functional and procedural means to transfer data between network entities with interoperability and interconnectivity to other layers, but from a security perspective, the data-link layer presents its own challenges. Cisco Catalyst switches are the leader in the switching market and major players in today's networks. With the rapid growth of IP networks in the past years, high-end switching has played one of the most fundamental and essential roles in moving data reliably, efficiently, and securely across networks. The chapter also provides guidelines and recommendations intended to help you understand and configure the Layer 2 security features available on Cisco switches to build robust networks.ДЄ summary of Layer 2 best practices is provided toward the end of the chapter. The chapter examines the integrated security features available on Cisco catalyst switches to mitigate threats that result from the weaknesses in Layer 2 of the OSI model. The current trend is for network security to be solidified through the support of switch security features that build feature-rich, high-performance, and optimized networks.

Switches act as arbiters to forward and control all the data flowing across the network. These threats result from weaknesses in Layer 2 of the OSI model-the data-link layer. This chapter describes Layer 2 security basics and security features on switches available to combat network security threats.

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