down

What is Down (in computer networking)?

The state of a network when some or all network communications are disrupted. Common reasons for networks being down include:

• Loose connectors on cables
• Breaks or shorts in cables
• Failed networking components

Indications that the network might be down include

• Users complain that they can’t log on to the network or access certain network resources.
• Alarm systems in Simple Network Management Protocol (SNMP) management software start sending administrative alerts or e-mail to administrators.
• The uninterruptible power supply (UPS) unit in the wiring closet generates its annoying high-pitched tone.