Cisco Catalyst 4500 Series Command Reference Guide

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Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
udld (interface configuration mode)
udld (interface configuration mode)
To enable UDLD and Fast UDLD on an individual interface or to prevent a fiber-optic interface from
being enabled by the udld (global configuration mode) command, use the udld interface level command.
Use the no form of this command to disable UDLD, or to return a nonfiber port to the setting specified
with the udld (global configuration mode) command.
udld port {aggressive | disable}
no udld port {aggressive | disable}
udld fast-hello interval
no udld fast-hello
Syntax Description
Defaults The fiber-optic interfaces are enabled with the state of the global udld (enable or aggressive) command.
The nonfiber interfaces are enabled with UDLD disabled.
Fast UDLD is disabled.
Command Modes Interface configuration
Command History
Usage Guidelines If you enable aggressive mode, once all the switch port’s neighbors have aged out either in the
advertisement or in the detection phase, UDLD and Fast UDLD restart the linkup sequence. They can
resynchronize with any potentially out-of-sync neighbor and shut down the port if the UDLD messages
from the neighbor indicate that the link state is still undetermined
Use the udld port aggressive command on fiber-optic ports to override the setting of the global udld (enable
or aggressive) command. Use the no form of the command on fiber-optic ports to restore the UDLD state as
configured by the global udld command.
If udld enable is configured globally, UDLD is enabled on all fiber-optic interfaces in
nonaggressive mode. You can configure udld port aggressive on a fiber-optic interface to override
the udld enable command setting and to enter aggressive mode. If you enter the
no udld port aggresive command, the settings of the previous global state are reestablished and the
aggressive mode is removed.
aggressive Enables UDLD in aggressive mode.
disable Disables UDLD.
fast-hello Enables Fast UDLD with the configured timer.
interval Sets the timer interval.
Release Modification
12.1(8a)EW Support for this command was introduced on the Catalyst 4500 series switch.
12.2(54)SG Support was added for Fast UDLD.

Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E