Multilayer switching is hardware-based switching and routing,
integrated into a single platform. In some cases, the frame and packet
forwarding operation is handled by the same specialized hardware ASIC and other
specialized circuitry. A multilayer switch does everything to a frame and
packet that a traditional switch or router does, including the following:
- Provides multiple simultaneous switching paths
- Segments broadcast and failure domains
- Provides destination specific frame forwarding based on Layer 2
information
- Determines the forwarding path based on Layer 3 information
- Validates the integrity of the Layer 2 frame and Layer 3 packet via
checksums and other methods
- Verifies packet expiration and updates accordingly
- Processes and responds to any option information
- Updates forwarding statistics in the Management Information Base (MIB)
- Applies security and policy controls, if required
- Provides optimal path determination
- The more expensive or sophisticated multilayer switches are modular and
support a wide variety of media types and port densities.
- Has the ability to support QoS
- Has the ability to support VoIP and in-line power requirements
Because it is designed to handle high-performance LAN traffic, a
multilayer switch can be placed anywhere within the network, cost-effectively
replacing the traditional switches and routers. Generally, however, a
multilayer switch may be more than is required to provide end systems access to
network resources.