Solid State Logic C10 HD, Installation Manual, Page: 211 / 237

K: SNMP
C10 HD Installation Manual Section 6: Appendices | Page 6-25
K: SnMp
SNMP (Simple Network Management Protocol) is a generic network management structure that can be applied to any
networked appliance for which remote or distributed monitoring is required. In a typical SNMP configuration, there will
be a number of systems to be managed or monitored and one or more additional systems present to manage them. A
prerequisite for this is that all monitored appliances must be accessible via an Ethernet network in some way.
In the case of the C10 HD system, the Blackrock DSP card, the console control surface and the RIO I/O unit are all
systems which can be managed – access is facilitated by the SBC Linux processor. The system management function itself
will be provided by a third party management system (or systems) – the SBC acts simply as an SNMP agent or bridge,
communicating with the SSL system(s) and passing that information on via SNMP.
There are, at the time of writing, three ‘versions’ of SNMP, known simply as ‘SNMPv1’, ‘SNMPv2’ and ‘SNMPv3’. The SBC
at this time supports both versions 1 and 2 but not version 3. Each version of SNMP is an enhancement on the previous
one where version 2 improves use and flexibility of the protocol whilst version 3 largely adds additional security features.
There are at present no plans to implement SNMPv3.
h
ow
i
t
w
oRKS
The SNMP agent application running on the SBC accepts SNMP requests from the management system and in turn
requests the required information from the Blackrock DSP card across the SSL network connection. Responses from the
Blackrock DSP card are interpreted by the SNMP agent and returned to the management system. For example, if the
management system submits a request for the system software version, the agent application on the SBC will send the
relevent Ethernet request to the Blackrock DSP card, interpret the response and respond to the management system with
the temperature measurement as follows:
• The management system sends a ‘
GET object sslC10SoftwareVerString
’ command.
• The SBC sends an matching SNMP request over Ethernet to the Blackrock DSP card.
• The SBC extracts the data from the response and sends it back to the management system.
SnMp t
RApS
By using an SNMP structure called a ‘trap’, an SNMP message can also be initiated by the agent application and sent to the
network management system autonomously. This therefore means that the network management system does not have
to continuously poll each agent for every possible status but will still be able to report on both major and minor issues.
Using this structure therefore the SBC’s agent application can flag – without receiving a request from the management
system – significant error events such as DSP failures or a software crash.
L
ocAL
c
onFiGURAtion
Configuration of what status information can be requested and which errors are flagged via a trap are defined in the SBC’s
‘Management Information Base’ or MIB for short. This is located on the SBC and will be found in the /usr/share/snmp/mibs
folder. There will be two MIB files found here; one for the Blackrock DSP card (and console) and one for the B-RIO. In
addition to requesting status information, management systems can also set any objects that are defined as read/writeable
in the MIB although in the C10 HD implementation no parameters are set as writable – most of the objects defined in the
MIBs, such as the power supply voltages, up-time, temperature etc. can’t be written to anyway for what should be obvious
reasons…
Communication between the management system, the SNMP agent and the Blackrock DSP card is all by reference to the
relevent entry in the MIB files. It is therefore important that the management system has access to the correct MIB files for
the version of system software that the C10 HD is running. A full list of the MIB objects currently available will be found later
in this section.