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SNMP
SIMPLE NETWORK MANAGEMENT PROTOCOL
SNMP (Simple Network Management Protocol) is a set of protocols for monitoring
widely distributed networks. The first versions of SNMP were developed as early
as the 1980s, and SNMP is now widely adopted in the IT industry. This functionality
is based on the manager/agent model, meaning that a network manager can
access the data stored in remote devices. It is particularly well suited for network
alarm monitoring and making networks more reliable. The main application
today is monitoring routers to retrieve network status information.
This protocol is only applicable over TCP/IP networks, as it is based on this protocol
stack. The small number of commands used and the independence between
agents and managers make SNMP a simple, robust protocol. These two factors
have contributed strongly to its widespread use.
HOW SNMP WORKS
3
INGENICO’S SNMP IMPLEMENTATION
3
EXAMPLE USES
5
DYNAMIC STATISTICS
5
PREVENTIVE DIAGNOSTICS
5
DYNAMIC TERMINAL MANAGEMENT
5
CONCLUSION
5
SNMP
The final message (Trap) allows the agent to
HOW SNMP WORKS
inform the manager of a significant event.
SNMP is based on the manager/agent model. This
model allows SNMP managers to remotely access
information stored by agents. The manager and
agent use a Management Information Base (MIB)
and a short set of commands to exchange
information, making the SNMP protocol light and
easy to implement.
Most of the messages are issued only by the
SNMP manager. The Trap message is the only one
initiated by the agent, and is typically used to notify
the manager of an alarm condition – before the
manager queries that object.
When the agent detects that one of its objects
listed for SNMP has been modified, it generates
a Trap message to inform the manager. This allows
MANAGEMENT
SYSTEM
MANAGER
HUMAN
NETWORK
MANAGER
TARGET
the manager to deal with the new value more
proactively, as opposed to waiting for the next time
NETWORK
PROTOCOL
MESSAGES
that particular object is queried.
AGENT
Managed
Objects
Database
Figure 1. Basic SNMP model
SNMP uses only five basic messages to manage
communication between the manager and agent.
The first two messages (Get, GetNext) allow the
SNMP’S ADVANTAGES
• It is LAN/WAN based. Because SNMP allows
data transfer over existing LAN/WAN networks, it
significantly cuts deployment and operating costs.
• It is an open standard. SNMP is available
free-of-charge, is documented extensively, and is
supported by most telecoms equipment providers.
• It is expandable. Although SNMP is light and simple,
it can be expanded to support a wide variety of
connected devices.
manager to request information for a specific object
or list of objects. The agent then replies through
a GetResponse message that contains either the
requested information or an error code (the Third
message).
• It is platform-independent. An SNMP manager can
be configured through the Management Information
Base (MIB) to enable data transfer with any device
supporting SNMP (e.g., combined IT & POS
environments).
When the manager wants to obtain the value
of an object, it creates a Get message that includes
the Object Identifier (OID) for each object of interest,
and sends this message to the agent. The agent
INGENICO’S SNMP IMPLEMENTATION
then checks whether the OIDs are included in its
SNMP has been implemented by Ingenico across
base. If they are, it replies with the objects’ value;
its product lines, in order to support customers in
if they are not, it sends an error code.
remote POS administration. This implementation
The fourth message (Set) allows the manager
was carried out through an LNET library upgrade,
to request a change in the value of a specific
the addition of an SNMP agent in the new
variable. To reply, the agent uses the GetResponse
LSNMP library, and an OS upgrade. Ingenico’s
message to either provide the information or give
implementation is fully compliant with the standard
an error code.
and is based on version 2.c SNMP.
INGENICO 2007
3.
The SNMP module is launched automatically
TCP/IP stack information provides details on
when a terminal is booted, and offers immediate
the amount of data sent and received, the protocol
functionality to the agent (the SNMP function
used, the transfer success rate, etc. Applications
can be deactivated if needed). This protocol can
can also generate specific counters for tracking
be used by any terminal with a TCP/IP stack:
targeted indicators.
Ethernet, WiFi, Bluetooth, GPRS, CDMA, etc.
SNMP can be used to retrieve statistical data
All this information is stored by the SNMP agent
to be presented to the remote manager. However,
about POS terminals that is stored on a central
an application can specify that its information
network manager. Three types of data can be
be non-public, in which case the agent will not
obtained:
send it to the manager.
The network manager collects data from
• OS data;
the terminal through regular contact at defined time
• TCP/IP stack information;
intervals, and can reset some counters to enable
• Application data.
fully automated management. For example, the
number of Visa or MasterCard cards used on the
The OS data include:
terminal can be counted over a set time period, then
• Number of terminal boots;
reset to zero at the start of the next time period.
• Number of pixel lines printed;
The schematic below illustrates the SNMP
• Number of magnetic cards swiped
(and with at least one good track read);
agent response when OS, TCP/IP, and application
objects are declared.
• Number of smart cards inserted
(asynchronous or synchronous);
• Number of modem calls
(and successful modem calls);
Application
• Number of keys pressed.
TCP/IP
stack
This data can be activated on all Ingenico
terminals. The schematic below illustrates how
OS data is retrieved using SNMP.
Application
statistics
OS
LSNMP
agent
TCP/IP
stack
information
OS data
LSNMP
manager
INTERNET
Application
TCP/IP
stack
LSNMP
agent
OS
OS data
LSNMP
manager
Figure 3. SNMP functionality with OS, TCP/IP, and application objects
INTERNET
Ingenico has also implemented the Trap message
discussed earlier, which is used by the terminal
to notify the network manager that an object has
been modified. The manager can thus check the
Figure 2. SNMP retrieval of OS data
object immediately to view the updated information.
INGENICO 2007
4.
The Trap message is useful for tracking statistics
like paper status or reboot sequence, and allows
real-time control of a group of terminals without
• Payment statistics, so that banks can adapt their
services to retailers’ needs
(e.g., specific functions for low payments, a new
telecom subscription offer, etc.)
the need for a field technician. Alerts of object
modifications are sent automatically by the
application to one or more network managers.
Another benefit of the Trap message is that it
can work the other way round. A network manager
can set a new value in an application's object,
PREVENTIVE DIAGNOSTICS
• Dynamic trouble-shooting
• Field preventive maintenance
(e.g., the early detection of an increase in modem
call failure or magnetic strip reading)
which will then force the application to launch
an OS update or data collection sequence.
DYNAMIC TERMINAL MANAGEMENT
EXAMPLE USES
• Modifications to data transfer connections
between agents and servers
SNMP is now a common technology and increasingly
available on network servers. Thanks to SNMP
standards, Ingenico customers can manage their
terminals easily through a single application
on a server. Ingenico customers can access SNMP
terminals from any structure supporting TCP/IP,
so that implementation can be a simple extension
• Automatic maintenance procedure generation
(i.e., if a server detects a possible incompatibility
with an application or updated communication
parameters, it can automatically request that
the agent launch an application upgrade through
the SNMP manager)
• Terminal queries for parameter and/or
configuration upgrades
of an existing IT administration application
or a bank or third-party server.
Moreover, implementing SNMP facilitates the
administration of a group of Ingenico terminals.
More specifically, it can be used for the following:
CONCLUSION
By implementing the SNMP technology, Ingenico
has again demonstrated its desire to provide
customers with the best-suited and most
light protocol is easy to deploy, and allows Ingenico
• Network performance based on TCP/IP data
terminals to be integrated into an existing SNMP
• Transaction volume data
environment if needed.
Groupe Ingenico
192, avenue Charles de Gaulle
92200 Neuilly-sur-Seine - France
Tel : +33 (0)1 46 25 82 00
Fax : +33 (0)1 47 72 56 95
www.ingenico.com
02-2007
cost-effective solutions available. This widespread,
DYNAMIC STATISTICS