D-Link DES-3326 - Manual (Page 27)

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
SNMP
The Simple Network Management Protocol (SNMP) is an OSI layer 7 (the application layer) protocol for
remotely monitoring and configuring network devices. SNMP enables network management stations to
read and modify the settings of gateways, routers, switches, and other network devices. SNMP can be
used to perform many of the same functions as a directly connected console, or can be used within an
integrated network management software package such as DView or NetView.
SNMP performs the following functions:
• Sending and receiving SNMP packets through the IP protocol.
• Collecting information about the status and current configuration of network devices.
• Modifying the configuration of network devices.
The DES-3326 has a software program called an ‘agent’ that processes SNMP requests, but the user
program that makes the requests and collects the responses runs on a management station (a
designated computer on the network). The SNMP agent and the user program both use the UDP/IP
protocol to exchange packets.
Authentication
The authentication protocol ensures that both the router SNMP agent and the remote user SNMP
application program discard packets from unauthorized users. Authentication is accomplished using
‘community strings’, which function like passwords. The remote user SNMP application and the router
SNMP must use the same community string. SNMP community strings of up to 20 characters may be
entered under the Remote Management Setup menu of the console program.
Traps
Traps are messages that alert network personnel of events that occur on the Switch. The events can be
as serious as a reboot (someone accidentally turned OFF the Switch), or less serious like a port status
change. The Switch generates traps and sends them to the trap recipient (or network manager).
Trap recipients are special users of the network who are given certain rights and access in overseeing
the maintenance of the network. Trap recipients will receive traps sent from the Switch; they must
immediately take certain actions to avoid future failure or breakdown of the network.
You can also specify which network managers may receive traps from the Switch by entering a list of
the IP addresses of authorized network managers. Up to four trap recipient IP addresses, and four
corresponding SNMP community strings can be entered.
SNMP community strings function like passwords in that the community string entered for a given IP
address must be used in the management station software, or a trap will be sent.
The following are trap types the switch can send to a trap recipient:
• Cold Start This trap signifies that the Switch has been powered up and initialized
such that software settings are reconfigured and hardware systems are rebooted. A
cold start is different from a factory reset in that configuration settings saved to non-
volatile RAM used to reconfigure the switch.
• Warm Start This trap signifies that the Switch has been rebooted, however the POST
(Power On Self-Test) is skipped.
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