Snmp Message Standard - 3Com V7111 - VCX 4 Channels Analog FXO Media Gateway User Manual

SNMP Message Standard

Four types of SNMP messages are defined:
Get – Request that returns the value of a named object.
Get-Next – Request that returns the next name (and value) of the next object supported
by a network device given a valid SNMP name.
Set – Request that sets a named object to a specific value.
Trap – Message generated asynchronously by network devices. It notifies the network
manager of a problem apart from polling of the device.
Each of the following message types fulfills a particular requirement of network managers:
Get Request – Specific values can be fetched using the get request to determine the
performance and state of the device. Typically, many different values and parameters
can be determined using SNMP without the overhead associated with logging into the
device, or establishing a TCP connection with the device.
Get Next Request – Enables the SNMP standard network managers to walk through all
SNMP values of a device (using the get-next request) to determine all names and values
that the device supports. This is accomplished by beginning with the first SNMP object to
be fetched, fetching the next name with a get-next, and repeating this operation until an
error is encountered (indicating that all MIB object names have been walked).
Set Request –The SNMP standard provides a method of effecting an action associated
with a device (using the set request) to accomplish activities such as disabling interfaces,
disconnecting users, clearing registers, etc. This provides a way of configuring and
controlling network devices using SNMP.
Trap Message – The SNMP standard furnishes a mechanism by which devices can
reach out to a network manager on their own (using the trap message) to notify the
manager of a problem with the device. This typically requires each device on the network
to be configured to issue SNMP traps to one or more network devices that are awaiting
these traps. The Trap messages are send to SNMP Manager. The IP address of SNMP
Manager is defined in the INI file or using a web browser (in Network Settings).
104 3Com VCX V7111 VoIP SIP Gateways User Manual