* A layer 3 switch is a device that can perform both switching and routing functions. It can forward packets based on the destination IP address, which is the information used to identify different subnetworks. A layer 3 switch can also create and manage multiple VLANs, which are logical subnetworks within a physical network. Therefore, a layer 3 switch can allow communication between two different subnetworks.
* A router is a device that connects multiple IP networks and forwards packets based on the destination IP address. A router can also perform network address translation (NAT), which allows devices with private IP addresses to communicate with devices with public IP addresses. Therefore, a router can allow communication between two different subnetworks, especially if they use different address spaces.
* An IDS (intrusion detection system) is a device that monitors network traffic and detects malicious or anomalous activities. An IDS does not forward packets or allow communication between subnetworks, but rather alerts the network administrator or takes preventive actions when a threat is detected.
* An access point is a device that allows wireless devices to connect to a wired network. An access point does not forward packets or allow communication between subnetworks, but rather acts as a bridge between the wireless and wired segments of the network.
* A layer 2 switch is a device that forwards frames based on the destination MAC address, which is the information used to identify devices within the same subnetwork. A layer 2 switch does not perform routing or network segmentation, and therefore cannot allow communication between different subnetworks.
* A media converter is a device that converts signals between different types of media, such as copper and fiber. A media converter does not forward packets or allow communication between subnetworks, but rather enables devices with different physical interfaces to connect to the same network.
References:
* Network Devices
* Routing and Switching Essentials
* CompTIA Network+ N10-008 Study Guide, Chapter 2: Devices and Infrastructure, pages 58-63, 72-75.