Hardware And Software Switching - Cisco Catalyst 4500 Series Configuration Manual

Catalyst 4500 Series Switch Implementation of CEF
Figure 33-1
Integrated Switching Engine (ASIC)
L3 physical
interface
Gig 1/1
The integrated switching engine performs inter-VLAN routing on logical Layer 3 interfaces with the
ASIC hardware. The ASIC hardware also supports a physical Layer 3 interface that can be configured
to connect with a host, a switch, or a router.
This section contains the following subsections:
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Hardware and Software Switching

For the majority of packets, the integrated switching engine performs the packet forwarding function in
hardware. These packets are hardware-switched at very high rates. Exception packets are forwarded by
the CPU subsystem software. Statistic reports should show that the integrated switching engine is
forwarding the vast majority of packets in hardware. Software forwarding is significantly slower than
hardware forwarding, but packets forwarded by the CPU subsystem do not reduce hardware forwarding
speed.
Figure 33-2
components.
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
33-4
Logical L2/L3 Switch Components
Logical Router
L3 logical
interfaces
VLAN1
L2 switchports
Hardware and Software Switching, page 33-4
Load Balancing, page 33-6
Software Interfaces, page 33-6
shows a logical view of the integrated switching engine and the CPU subsystem switching
Chapter 33
VLAN2
Configuring Cisco Express Forwarding
OL-25340-01