Accessing tables and parameters using snmp – ELSA Cable User Manual

Page 33

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Configuration modes

ELSA MicroLink Cable

25

English

SNMP V.1 has only a very limited set of commands at its disposal, as the table below
shows:

These commands can be used for central monitoring and configuration of SNMP-capable
devices on a network. The SNMP capabilities of the agents are specified in so-called
MIBs = Management Information Bases.

The firmware of ELSA routers includes an implementation for an SNMP V.1 agent (in
accordance with RFC 1157). A part of MIB-2 and a private MIB, included in the product
as a separate file, are supported. This MIB must be loaded and translated by an SNMP
manager (HP OpenView, for example) to allow you to manage a device completely using
SNMP. All menus and parameters of the remote configuration will then be available to
you on a single branch of the SNMP management tree:

Accessing tables and parameters using SNMP

Any of the tables and parameters can be read and modified as necessary via the SNMP
interface. This also involves specifying in the MIB the variables which should have 'read-
only' or 'read-write' status. Commercially available SNMP managers indicate 'read-only'
and 'read-write' status using color coding.

Access protection in SNMP V.1

Access to SNMP objects is controlled using so-called communities. A community is
basically a password used to govern access to particular classes of information. The
router permits read-only access to all parameters and tables through the 'public'
community. Bear in mind that this community cannot execute any write accesses.

You must use the device's password if you wish to write data using SNMP. Write access
using SNMP will not be granted as a matter of principle if the device's password is not
entered.

If the trapping mechanism is enabled and a failed access attempt is detected, an
'Authentication Failed' trap is triggered and sent to the manager(s) in the SNMP trap
table.

Command

Target/Source

Function

GetRequest

Manager – Agent

retrieves information from the agent

GetNextRequest

Manager – Agent

retrieves the information contained in
the following MIB from the agent

SetRequest

Manager – Agent

modifies a setting in the agent

GetResponse

Agent – Manager

returns the queried value to the man-
ager

Trap

Agent – Manager

reports on an error or special status

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