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| 1.2 |  | Key Characteristics of Various Switching Technologies |
| 1.2.3 |  | Layer 3 switching |

Layer 3 switching is hardware-based routing. The packet forwarding is handled by specialized hardware ASICs. The goal is to capture the speed of switching and the scalability of routing. A Layer 3 switch acts on a packet in the same way that a traditional router does, for example:

- Determining the forwarding path based on Layer 3 information
- Validating the integrity of the Layer 3 header via checksum
- Verifying packet expiration and updates accordingly
- Processing and responding to any option information
- Updating forwarding statistics in the Management Information Base (MIB)
- Applying security controls if required
- Implementing QoS

The primary difference between the packet-switching operation of a router and a Layer 3 switch lies in the physical implementation. In general-purpose routers, microprocessor-based engines typically perform software-based packet switching. A Layer 3 switch performs packet switching with hardware. Because it is designed to handle high-performance LAN traffic, a Layer 3 switch can be placed anywhere within the network, offering a cost-effective alternative to the traditional router.