Cisco 500 Series Administration Guide

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Cisco 500 Series Stackable Managed Switch Administration Guide 202
Port Management: Unidirectional Link
Detection
This section describes how the Unidirectional Link Detection (UDLD) feature.
It covers the following topics:
• UDLD Overview
• UDLD Operation
• Usage Guidelines
• Dependencies On Other Features
• Default Settings and Configuration
• Before You Start
• Common UDLD Tasks
• Configuring UDLD
UDLD Overview
UDLD is a Layer 2-protocol that enables devices connected through fiber-optic or
twisted-pair Ethernet cables to detect unidirectional links. A unidirectional link
occurs whenever traffic from a neighboring device is received by the local device,
but traffic from the local device is not received by the neighbor.
The purpose of UDLD is to detect ports on which the neighbor does not receive
traffic from the local device (unidirectional link) and to shut down those ports.

Cisco 500 Series Specifications

General

Model	Cisco 500 Series
Category	Switch
Mounting	Rack-mountable
Management	Web-based, CLI, SNMP
Ports	24, 48
Port Speed	10/100/1000 Mbps
PoE Support	Available on some models
Switching Capacity	Up to 176 Gbps
MAC Address Table Size	16, 000 entries
Security	ACLs, 802.1X
Quality of Service (QoS)	Yes
Dimensions	Varies by model
Weight	Varies by model
Humidity	10% to 90% non-condensing
Power Supply	Internal
Power Consumption	Varies by model
Jumbo Frame Support	Up to 9216 bytes