Cisco Catalyst X4232 Installation And Configuration Note page 35

Remote Monitoring
Layer 3 switching software supports the first four Remote Monitoring (RMON) groups.
RMON is a network management protocol for gathering network information and monitoring traffic
data within remote LAN segments from a central location. RMON allows you to monitor all nodes and
their interaction on a LAN segment. RMON, used with the SNMP agent in the switch router, allows you
to view both the traffic that flows through the router and segment traffic not necessarily destined for the
switch router. Layer 3-switching software combines RMON alarms and events with existing MIBs so
you can choose where monitoring will occur.
Refer to the Cisco IOS Configuration Fundamentals Configuration Guide for more information about
RMON.
Cisco Discovery Protocol
CDP is a device-discovery protocol that is both media and protocol independent. CDP is available on
all Cisco products, including routers, switches, bridges, and access servers. Using CDP, a device can
advertise its existence to other devices and receive information about other devices on the same LAN.
CDP enables Cisco products to exchange information with each other regarding their MAC addresses,
IP addresses, and outgoing interfaces. CDP runs over the data link layer only, which allows two systems
that support different network-layer protocols to learn about each other. Each device configured for
CDP sends periodic messages to a multicast address. Each device advertises at least one address at
which it can receive Simple Network Management Protocol (SNMP) messages.
Cisco Express Forwarding
Layer 3-switching software features CEF. CEF is advanced Layer 3 IP-switching technology. CEF
optimizes network performance and scalability for networks with large and dynamic traffic patterns,
such as the Internet, on networks characterized by 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.
CEF manages route distribution and forwarding by distributing routing information from the central
processor to the individual Ethernet interfaces. This technology, used within the Internet, provides
scalability in large campus core networks. CEF provides Layer 3 forwarding based on a topology map
of the entire network, resulting in high-speed routing table lookups and forwarding.
One of the key benefits of CEF in Layer 3 switching is its routing convergence. Because the FIB is
distributed to all interfaces, whenever a route goes away or is added, the FIB updates that information
and provides it to the interfaces. Central processor interrupts are minimized. The interfaces receive the
new topology very quickly and reconverge around a failed link based on the routing protocol being used.
We recommend that you only issue any CEF load balancing configuration commands. Do not issue
Caution
any other CEF configuration commands. The CEF default settings should not be altered; doing so
may adversely affect the performance of your system.
Load Balancing
A switch router that employs load balancing can distribute traffic over all its network ports that are the
same distance from the destination address. Load balancing increases the utilization of network
segments and increases effective network bandwidth.
78-10164-03
Overview of the Catalyst 4003 and 4006 Layer 3 Services Module Interfaces
Installation and Configuration Note for the Catalyst 4000 Layer 3 Services Module
35