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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 1 Product Overview Layer 3 Software Features
ETH-AIS suppresses alarms following detection of defect conditions at the server (sub) layer. Due to
independent restoration capabilities provided within the Spanning Tree Protocol (STP) environments,
ETH-AIS is not expected to be applied in the STP environments. In this case, AIS is configurable, and
you can enable and disable AIS in STP environment or not.
ETH-RDI can be used by a MEP to communicate to its peer MEPs that a defect condition has been
encountered. ETH-RDI is used only when ETH-CC transmission is enabled.
For information about Y.1731, see Chapter 58, “Configuring Y.1731 (AIS and RDI).”
Layer 3 Software Features
A Layer 3 switch is a high-performance switch that has been optimized for a campus LAN or an intranet,
and it provides both wirespeed Ethernet routing and switching services. Layer 3 switching improves
network performance with two software functions: route processing and intelligent network services.
Compared to conventional software-based switches, Layer 3 switches process more packets faster by
using application-specific integrated circuit (ASIC) hardware instead of microprocessor-based engines.
The following sections describe the key Layer 3 switching software features on the Catalyst 4500 series
switch:
Cisco Express Forwarding, page 1-11
EIGRP Stub Routing, page 1-12
Enhanced Object Tracking, page 1-12
GLBP, page 1-12
HSRP, page 1-12
In Service Software Upgrade, page 1-15
IP Routing Protocols, page 1-13
IPv6, page 1-15
Multicast Services, page 1-15
NSF with SSO, page 1-17
OSPF for Routed Access, page 1-17
Policy-Based Routing, page 1-17
Unidirectional Link Routing, page 1-17
VRF-lite, page 1-18
Virtual Router Redundancy Protocol, page 1-18

Cisco Express Forwarding

Cisco Express Forwarding (CEF) is an advanced Layer 3 IP-switching technology. CEF optimizes
network performance and scalability in networks with large and dynamic traffic patterns, such as the
Internet, and on networks that use intensive web-based applications or interactive sessions. Although
you can use CEF in any part of a network, it is designed for high-performance, highly resilient Layer 3
IP-backbone switching.
For information on configuring CEF, see Chapter 31, “Configuring Cisco Express Forwarding.