Cisco Express Forwarding - Cisco Catalyst 4500 Series Configuration Manual

Layer 3 Software Features
Bidirectional Forwarding Detection (BFD) protocol. BFD is a detection protocol designed to provide
fast forwarding path failure detection times for all media types, encapsulations, topologies, and routing
protocols. It includes a description of how to configure multihop BFD sessions. BFD provides a
consistent failure detection method for network administrators in addition to fast forwarding path failure
detection.
For information on configuring BFD, see

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
EIGRP Stub Routing
The EIGRP stub routing feature, available in all images, reduces resource utilization by moving routed
traffic closer to the end user.
The IP base image contains only EIGRP stub routing. The IP services image contains complete EIGRP
routing.
In a network using EIGRP stub routing, the only route for IP traffic to follow to the user is through a
switch that is configured with EIGRP stub routing. The switch sends the routed traffic to interfaces that
are configured as user interfaces or are connected to other devices.
For information on configuring EIGRP Stub Routing, see
Enhanced Object Tracking
Before the introduction of the Enhanced Object Tracking feature, the Hot Standby Router Protocol
(HSRP) had a simple tracking mechanism that allowed you to track the interface line-protocol state only.
If the line-protocol state of the interface went down, the HSRP priority of the router was reduced,
allowing another HSRP router with a higher priority to become active.
The Enhanced Object Tracking (EOT) feature separates the tracking mechanism from HSRP and creates
a separate standalone tracking process that can be used by other Cisco IOS processes as well as HSRP.
This feature allows tracking of other objects in addition to the interface line-protocol state.
A client process, such as HSRP, Virtual Router Redundancy Protocol (VRRP), or Gateway Load
Balancing Protocol (GLBP), can now register its interest in tracking objects and then be notified when
the tracked object changes state.
For details on EOT, refer to this URL:
For platform specific information on Enhanced Object Tracking, see
Enhanced Object Tracking."
For more detailed information on Enhanced Object Tracking, see the URL:
http://www.cisco.com/en/US/docs/ios-xml/ios/ipapp/configuration/12-4t/iap-eot.html
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
1-12
Chapter 37, "Configuring Bidirection Forwarding Detection."
Chapter 33, "Configuring Cisco Express Forwarding."
Chapter 32, "Configuring Layer 3 Interfaces."
Chapter 1 Product Overview
Chapter 57, "Configuring
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