Cisco Catalyst 2960-X Command Reference

udld port
To enable UniDirectional Link Detection (UDLD) on an individual interface or to prevent a fiber-optic interface
from being enabled by the udld global configuration command, use the udld port command in interface
configuration mode. To return to the udld global configuration command setting or to disable UDLD if entered
for a nonfiber-optic port, use the no form of this command.
udld port [aggressive]
no udld port [aggressive]
Syntax Description
(Optional) Enables UDLD in aggressive mode on the specified interface.aggressive
Command Default
On fiber-optic interfaces, UDLD is disabled and fiber-optic interfaces enable UDLD according to the state of
the udld enable or udld aggressive global configuration command.
On nonfiber-optic interfaces, UDLD is disabled.
Command Modes
Interface configuration
Command History
ModificationRelease
This command was introduced.Cisco IOS 15.0(2)EX
Usage Guidelines
A UDLD-capable port cannot detect a unidirectional link if it is connected to a UDLD-incapable port of
another switch.
UDLD supports two modes of operation: normal (the default) and aggressive. In normal mode, UDLD detects
unidirectional links due to misconnected interfaces on fiber-optic connections. In aggressive mode, UDLD
also detects unidirectional links due to one-way traffic on fiber-optic and twisted-pair links and due to
misconnected interfaces on fiber-optic links.
To enable UDLD in normal mode, use the udld port interface configuration command. To enable UDLD in
aggressive mode, use the udld port aggressive interface configuration command.
Use the no udld port command on fiber-optic ports to return control of UDLD to the udld enable global
configuration command or to disable UDLD on nonfiber-optic ports.
Use the udld port aggressive command on fiber-optic ports to override the setting of the udld enable or udld
aggressive global configuration command. Use the no form on fiber-optic ports to remove this setting and to
return control of UDLD enabling to the udld global configuration command or to disable UDLD on
nonfiber-optic ports.
You can use these commands to reset an interface shut down by UDLD:
•
The udld reset privileged EXEC command resets all interfaces shut down by UDLD.
Catalyst 2960-X Switch Layer 2 Command Reference, Cisco IOS Release 15.0(2)EX
OL-29043 -01 123
Layer 2 Commands
udld port

Cisco Catalyst 2960-X Specifications

General

Console port	RJ-45
USB 2.0 ports quantity	2
SFP module slots quantity	4
Installed SFP modules quantity	-
Gigabit Ethernet (copper) ports quantity	48
Basic switching RJ-45 Ethernet ports type	Gigabit Ethernet (10/100/1000)
Power source	AC
Input current	5 A
AC input voltage	100 - 240 V
Power consumption (typical)	60.9 W
Number of power supply units	1
Redundant power supply (RPS) support	Yes
Operating altitude	0 - 3000 m
Non-operating altitude	0 - 4000 m
Storage temperature (T-T)	-25 - 70 °C
Operating temperature (T-T)	-5 - 40 °C
Operating relative humidity (H-H)	10 - 95 %
Switching protocols	UDP, TCP, RADIUS/TACACS+
Number of VLANs	1023
Networking standards	IEEE 802.1ab, IEEE 802.1D, IEEE 802.1p, IEEE 802.1Q, IEEE 802.1s, IEEE 802.1w, IEEE 802.1x, IEEE 802.3, IEEE 802.3ab, IEEE 802.3ad, IEEE 802.3ae, IEEE 802.3af, IEEE 802.3ah, IEEE 802.3at, IEEE 802.3az, IEEE 802.3u, IEEE 802.3x, IEEE 802.3z
Throughput	107.1 Mpps
Jumbo frames	9216
Number of queues	8
MAC address table	16000 entries
Number of static routes	1000
DHCP features	DHCP server
Authentication	MAC-based authentication, Port-based authentication
Security algorithms	802.1x RADIUS, SNMP, SSH
Access Control List (ACL) rules	3
Switch type	Managed
Switch layer	L2/L3
Safety	UL 60950-1, CAN/CSA-C22.2 No. 60950-1, EN 60950-1, IEC 60950-1, AS/NZS 60950-1
Form factor	1U
Product color	Black
Total Power over Ethernet (PoE) budget	370 W
Power over Ethernet (PoE) ports quantity	24
Power over Ethernet plus (PoE+) ports quantity	12
Memory type	DRAM
Noise level	39 dB
Flash memory	128 MB
Internal memory	512 MB
Processor frequency	600 MHz
Mean time between failures (MTBF)	276870 h

Weight and Dimensions

Depth	368 mm
Width	445 mm
Height	45 mm
Weight	5800 g