Sonnet Technologies Fusion RAID Configuration Tool and Utilities Operation Manual - Manual (Page 51)

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1.9 SNMP Configuration
SNMP is a standard network protocol that provides the ability to
monitor SNMP enabled systems from anywhere on the network.
Once configured, 3rd party MIB (Management Information Base)
browsers on a Management Station can be used to retrieve the current
configuration and receive TRAP messages when significant events occur.
Via the Configuration Tool, SNMP is supported only for the Sonnet
3 Gb/s RAID controller (listed as an ExpressSAS R380).
The ATTO SNMP agent has two modes, depending on your
configuration. If the only SNMP agent on your server is the
ATTO agent, the mode should be Enabled. If you have other
SNMP agents running and you want them to integrate their data
into a single tree of information or if you want to use advanced
SNMP features, choose SubAgent mode.
Definitions
• SNMP - Simple Network Management Protocol
• Network Node - An addressable device attached to a computer
network.
• Management Station - The host system that monitors network
nodes.
• Trap - An alert that is sent to a management station by agents.
• Agent - A software process on the system being monitored that
responds to queries using SNMP to provide status and statistics
about a network node.
• SubAgent - A software process on the system being monitored
that responds to SNMP queries from another agent, instead of
a MIB (
Management Information Base) browser. The request
from the other agent is generated when it is contacted by a MIB
browser.
Details
The ATTO SNMP agent supports protocol versions 1 and 2c.
Communication with the agent requires UDP over IPv4. The ATTO
specific information can be found under “attotech” in the “enterprises”
node (1.3.6.1.4.1.4547). Read-only support is provided.
Enabled Mode
This mode of operation provides Management Stations with
basic information for the standard OID (
Object IDentifier) tree,
as well as the ATTO specific information. While this mode will
also work if a system service is installed and running, the ATTO
agent must be configured to listen on a different port than the
system service to ensure both function properly. This mode is
required to support SNMP if the system SNMP service (such as,
Windows SNMP service or snmpd for OS X and Linux) is not
already running.
SubAgent Mode
This mode of operation relies on the operating system’s SNMP
service being installed as a Master Agent and running. All
Management Station requests must be directed to this Master
Agent,
not the ATTO agent. It is expected that only experienced
SNMP administrators will use this mode, as installing and
configuring the operating system services are beyond the scope
of this document. Examples are Windows SNMP services, or the
open-source Net-SNMP package.
In this mode, the system service is automatically reconfigured so
that when the service receives requests for the ATTO branch of the
OID tree, the request is delegated to the ATTO agent through the
loopback interface on a different port. While the primary benefit
of subagent mode is to allow the Master Agent to handle most
requests directly (the operating system services implement many
more MIBs than the ATTO agent), and to allow multiple subagents
to be merged into a single OID tree, this mode can be used to
enable features that are not supported by the ATTO agent.
For example, if the system service supports version 3 of the
protocol, all communication over the network between the
Management Station and the service can be encrypted using the
desired privacy options of version 3. The system service will then
communicate to the ATTO agent using one of the supported
protocols.
Note: For security purposes, the ATTO agent will only respond to
requests through the loopback interface when in subagent
mode. If the system service is stopped, the ATTO agent will be
inaccessible from any other host on the network.
Note: Other features that are not directly supported by the ATTO agent,
but can be enabled with this configuration include source address
filtering and stronger authentication than simple community
strings provide. All of these features depend on properly
configuring the system service, and are beyond the control of the
ATTO agent. Refer to the documentation for the system service to
determine how to enable these features.
Note: On Windows Vista Service Pack 1 and Windows Server 2008, a
bug in the Microsoft SNMP service prevents subagent mode from
working correctly. This is a known issue that requires a hotfix:
http://support.microsoft.com/kb/950923. The bug has been
fixed in Service Pack 2. Enabled mode is not affected, nor is the
Net-SNMP service if that is being used as a replacement for the
Microsoft service.
Note: The Net-SNMP service that ships with Mac OS X 10.4 lacks the
functionality needed to support subagent mode. To work around
this, you need to use the enabled mode or build the Net-SNMP
package from source with proxy support enabled.