The Catalyst 4908G-L3 provides an aggregate throughput of close to 12 Mpps for Layer 3 switching (it performs at wire speed for its 8 interfaces yielding an aggregate of 11,904 Mpps.) These data rates apply not only tIP and IPX traffic but also to IP multicast and bridged traffic and are a result of using high-speed application-specific integrated circuit (ASIC) technology on each port to perform true Layer 3 switching. The Catalyst 4908G-L3 supports a high-performance architecture with 22 Gbps bandwidth. The switch fabric is capable of supporting all 8 Gigabit Ethernet ports simultaneously at wire speed.

The Catalyst 4908G-L3 is housed in a 1.5 RU chassis and can be provisioned with an optional external redundant power supply. It supports a 22 Gbps shared-memory, fully non-blocking switch fabric, a high-performance RISC processor which provides the routing intelligence, and individual port based ASICs for the Layer 3 switching. The Catalyst 4908G-L3 uses Cisco Express Forwarding (CEF), which has been developed for the Cisco 12000 Gigabit Switch Router (GSR), the Catalyst 8500, and the Cisco 7500. This technology provides Layer 3 switching based on a topology map of the entire network that is distributed teach port based ASIC, allowing it to make autonomous switching decisions without the involvement of a centralized CPU.