SNMP
TNCS Implementation of SNMP
SNMP (Simple Network Management Protocol) has become the
standard for managing networks of all forms. SNMP support is
simple to provide for a single managed object like a network
router or bridge. However, for a system like TNCS that manages
thousands of elements, providing SNMP access can be quite
difficult, especially in an environment where managed device
types are added on a weekly basis.
Existing SNMP tools require
that the base executable software be modified every time a new
device type is added. TNCS eliminates this requirement by
embedding SNMP object identifiers directly in the file that
defines the device type. The SNMP agent interface retrieves data
for managed objects using the object identifiers. Therefore,
SNMP access is automatically provided for a managed device type
using the embedded identifiers. An MIB (Management Information
Base) generation tool is provided to generate the MIB document
automatically from the managed device definition file.
Because of some of the
limitations of SNMP, network topology can be lost in the
implementation of the SNMP agent. TNCS provides complete
topology awareness by providing:
- access to the group
constructs
- the name of the parent
device for each managed object
Knowledge of the parent name
for each managed device and group allows complete reconstruction
of the hierarchical list maintained by TNCS.
TNCS has an SNMP agent that is
responsible for answering status queries (called Gets) and
responding to commands (called Sets). Whenever abnormal
conditions occur or clear, the agent sends unsolicited messages
to the NMS (called Traps).
Devices that interface to TNCS
do not speak SNMP protocol. TNCS has a SNMP proxy agent to take
data from these various devices and turn that data into Gets,
Sets, and Traps.
Messages are formatted and
interpreted using the SNMP MIB (Management Information Base).
Each device that is supported by TNCS has its associated entry
in the TNCS MIB. The MIB is loaded on both the third party
computer and the TNCS computer and governs their communications.
Network Management Systems communicate to TNCS using a software
component called an SNMP Manager.
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