* A redundant cluster of devices is a group of devices that can provide backup or failover functionality in case of a hardware failure or a network attack.
* Layer 2 devices operate at the data link layer of the OSI model and are responsible for forwarding
* frames based on MAC addresses. They include switches, bridges, and NICs.
* Multiple routers are not Layer 2 devices, but Layer 3 devices that operate at the network layer of the OSI model and are responsible for forwarding packets based on IP addresses. Therefore, option A is incorrect.
* Multiple switches are Layer 2 devices that can provide redundancy and scalability in the network by using protocols such as spanning tree, link aggregation, and VLANs. They can also support Layer 3 functions such as routing and inter-VLAN routing. Therefore, option B is the correct answer.
* Multiple firewalls are not Layer 2 devices, but Layer 4 devices that operate at the transport layer of the OSI model and are responsible for filtering traffic based on ports and protocols. They can also provide security services such as NAT, VPN, and IDS. Therefore, option C is incorrect.
* Multiple budges is a typo and should be multiple bridges. Bridges are Layer 2 devices that can divide a network into segments and reduce collisions. However, they are less efficient and less intelligent than switches, and they are rarely used in modern networks. Therefore, option D is incorrect.
References:
* CompTIA Network+ N10-008 Study Guide, Chapter 2: Network Devices, pages 47-48, 51-52, 55-56,
59-60.
* Professor Messer's Network+ Video Course, Section 1.1: Network Devices, videos 1.1.1 - 1.1.4, 1.1.6,
1.1.7.
* Cisco Press: Fully Redundant Layer 2 and Layer 3 Designs