In a typical enterprise network, what is the fundamental difference between routing and switching in terms of function and the information used to forward traffic?

Introduction / Context:
Routing and switching are two core functions in any IP network. Although modern multilayer devices can perform both roles, the underlying concepts remain distinct. Understanding how routing differs from switching is foundational for network design, troubleshooting, and certification exams.

Given Data / Assumptions:

• Routing operates at the network layer of the TCP/IP and OSI models.
• Switching operates primarily at the data link layer, especially in Ethernet LANs.
• Routing decisions are based on logical network addresses such as IP addresses.
• Switching decisions are based on physical addresses such as MAC addresses.

Concept / Approach:
Switches build a MAC address table by learning which MAC addresses appear on which ports. They use this table to forward Ethernet frames within a single broadcast domain or VLAN. Switching does not normally change the packet header at the network layer. Routers, in contrast, maintain routing tables that describe paths to different IP networks. When a router forwards a packet, it examines the destination IP address, consults the routing table, and sends the packet toward the appropriate next hop. Routers also create separate broadcast domains and can apply policies such as access control and quality of service between networks.

Step-by-Step Solution:
1. Identify what switching does: it forwards frames inside a local network segment or VLAN by inspecting destination MAC addresses.2. Recognize that this behavior occurs at OSI Layer 2, the data link layer.3. Identify what routing does: it forwards packets between different IP networks or subnets by examining destination IP addresses.4. Recognize that routing decisions occur at OSI Layer 3, the network layer.5. Compare the answer choices and select the one that clearly states that switching uses MAC addresses within a network, while routing uses IP addresses between networks.

Verification / Alternative check:
In practice, when a host sends a packet to a device in the same subnet, the Ethernet switch uses the destination MAC address to decide which port to forward the frame out of. When traffic is sent to a remote subnet, it is instead forwarded to the default gateway. The router at that gateway examines the IP header, consults its routing table, and forwards the packet toward the remote network. This operational behavior supports the conceptual difference described above.

Why Other Options Are Wrong:
Option A reverses the roles of routing and switching and therefore is incorrect. Option C incorrectly claims that both processes are identical and use only MAC addresses, which is not true for routing. Option D incorrectly limits routing to wireless networks and switching to wired networks, when in reality both functions are used across many types of media.

Common Pitfalls:
Because some devices are called multilayer switches and perform both routing and switching, learners sometimes blur the distinction between the two functions. It is important to remember that the difference lies not in the device name but in whether the forwarding decision is based on MAC addresses (switching) or IP addresses (routing). Keeping the OSI layer perspective in mind helps avoid confusion.

Final Answer:
Routing forwards packets between different IP networks using logical network layer addresses, while switching forwards frames within the same network using physical MAC addresses.