MANAGING NETWORK COMPONENTS USING SNMP
Abubucker Samsudeen Shaffi
Faculty of Computing Studies, Gulf College
Muscat, Sultanate of Oman.
Email: abobacker.shaffi@gulfcollegeoman.com
Mohanned Al-Obaidy
Faculty Head for Computing Awards, Gulf College
Muscat, Sultanate of Oman.
Email: mohaned@gulfcollegeoman.com
Abstract:
This paper is to be given an overview for the implementation of a Network Monitoring System to monitor the
network resources using SNMP (Simple Network Management Protocol). It consists of manager, agent and
managed services. The manager responsibility is to monitor the agents. The agents are software that manage all the
network devices and send the details report about the managed objects to the manager. The agent should manage
each network device based on the feedback received from the manager. It is an integrated part of the network
infrastructure enables the local administrator to perform real-time monitoring on a big network. It helps the
administrator to keep up his job more challenges. There are many problems are faced by the network administrator
during the manual monitoring of the whole network such as concerned with the performance, analyses and controls
of various components of the network. It is very difficult to identify the problems by the administrator. This paper
describes the process of SNMP and implementation in network.
Keywords: SNMP, NMS, MIB
1. INTRODUCTION TO NETWORK
MANAGEMENT
Network Management is more support for the
Network administrators to monitor and control the
hardware and software system that comprise an
internet. It can easily design and implement the
efficient and robust network infrastructure and also
record the status of nodes in their network. The main
goal of the network management is to detect and
correct number of problems occur in the network. The
network management supports network monitoring
system (NMS). The network administrator uses the
NMS to monitor, configure, to take statistic record
performance of the network devices and security of
the whole network in one place. The main function of
NMS is given below.
 NMS can be located on each segment of a
network
 NMS can observe and record the activity of
the network devices and also identify fault
and isolated the problems
 NMS monitors the network round the clock
without human intervention
 NMS can view the whole network traffic
from one location.
 NMS can identify how much the network
devices are used and how many packets are
sent and received by each network devices.
2. ISO NETWORK MANAGEMENT MODEL
ISO provides five network management functional
areas which are support to achieve the following
goals:
 Configuration management
 Fault management
 Performance management
 Accounting management
 Security management
2.1 Configuration Management
The network administrators can monitor and control
the network operations. When the administrators do
the configuration, the following things should
understand during the configuration.
 How the network are configure
 Identify the network devices name and IP
addresses
 Identify the network device operations and
relationship between the network devices
 Identify the routing details of each network
devices
 The
administrators
have
collected
configuration data for all the network
devices.
2.2 Fault Management
During the network operations, the network
administrators can able to find the abnormal network
operations which leads the whole network may be
shutdown. So the networks administrators must
detect, isolate, notify, and correct the fault during the
monitoring.
2.3 Performance Management
The network performance is very important for the
organization. The network administrators must be
analysis and measure all the network devices and
control the performance of the network devices
utilization, Throughput, packet delay and error rate.
The overall performance can be maintained at an
acceptable level. The main goal of this management
is to make the network performance optimally.
2.4 Accounting Management
In this management, the network administrators can
able to gather usage of information consumed by the
user and network devices. Based on this information,
the administrator can identify the cost for the network
services and also analysis of the existing network
load and proposal network capacity for the
organization. The administrator grants the privilege
for the user to access the network devices such as
add, delete new users and setting usage limitations.
2.5 Security Management
Security is very important for the organization to
keep their information more secure. The organization
network prevents the information from the
unauthorized person. The network administrators
provide access to network devices and corporate
resources to authorized persons. It concern with
monitoring of security
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intrusion detection
user security management (passwords)
Security configuration management
Example: firewalls and proxies
Security audits
Network monitoring system supports all the
functions of ISO network management. The
network monitor system is based on Graphical
User Interface (GUI). SNMP (Simple Network
Management Protocol) is one of the protocol
supports Network Monitoring System. It is a
powerful management tools to monitor the network
devices in local area network.
3. SCENARIO
The organizations may have small business, multienterprise business and multinational business
network. All these organization have both LANs and
WANs. Some organization network has more
application oriented. Some have faster connection
network between organizations. Some organization
uses remote applications. All these organization has
common thread from time to time. Every network has
its own problems, very few organizations have tools
to find the error and fix them because of its cost and
time. The big organization has a very large network.
It is very difficult to monitor and control manually.
These types of organization need NMS to remotely
control and monitor the network devices. If one
device is fails the other part of the device network
will be affected. The network is more congestion it
leads to delay to deliver the packets. Sometime the
performance of the network device is very slow.
There are many reasons for that. These entire
problems can be solved by the NMS using SNMP
management.
4. INTRODUCTION OF SIMPLE NETWORK
MANAGEMENT PROTOCOL (SNMP)
The network is composed of many different types of
devices. The operation of the network sometimes
works smoothly and sometime it would not. So the
network begins to experience problems. It becomes
very slow. It is possible the whole network are
monitored or analyzed without the network
administrator. Most of the devices on the network
support network management protocol. It facilitates
exchange of the management information between
network devices. Numbers of different protocols exist
to support network management. One of the
protocols is Simple Network Management Protocol
(SNMP). This protocol is very simple to operate,
easy to implement and industry standard protocol. It
plays an important role to monitor network
performance, to find the network problems and solve
those problems without human intervenes. The
Network administrator can easily find the
performance of the hardware devices in effective
ways and also record the performance details of the
hardware such as
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the average and peak network utilisation
the average and peak frame size
the average and peak number of frames per
second
the number of broadcasts domain
the number of collisions per second
the number of CRC errors during the frame
transmission
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network devices and give the response according
to manager request.The main responsible is to
maintaining local management information and
gives the feedback to a manager through SNMP.
All the management information are stored in its
MIB.
To determine the frame size during the
transmission such as the number of error
frame. Example. Short frame (runts) and
long frames (jabbers). Runts means the
frame size less than 64 bytes and jabber
means the frame size more than 1514.
Perform auto discovery of the network
devices.
Identification of the delay, throughput of
packet during the transmission.
Performance analyses are useful for analysis
the current system and identify the future
requirements needs for the organization.
Figure 2: Message flow between Manager and
Agent
The Figure-2 indicates the flow of messages between
SNMP Manager and SNMP Agent.

The manager can get the information from the
agent about their managed object information.

The manager can use get-next to get the next
object in the managed device.

The manager can use get-bulk to get group of
data from the agent.

The manager can use set to set the value of a
managed object.

The agent can able to send a trap to the
manager about some event occurs in managed
device
Figure 1: Diagram of Network Monitors
5. COMPONENT OF SIMPLE NETWORK
MANAGEMENT PROTOCOL (SNMP)
The Simple Network Management Protocol (SNMP)
is an application layer protocol in network
management. SNMP protocol can easily design and
implement
according
to
the
organization
requirements.
SNMP
enable
the
network
administrators to manage whole networks for the
organization. This protocol is a part of TCP/IP. Most
of the modern tools are support the SNMP.
SNMP consists of four components:
 The SNMP Manager has responsibility to
manage one or more agents from a remote place.
The Manager is software which is installing on
the server. The manager can query SNMP agents
by use of SNMP commands. When problems are
occurred, the agent automatically informs the
manager. The manager can also access the
management information of the agent. The SNMP
manager can also communicate to the network
devices using commands to changing values in an
agent’s database.
 The SNMP Agents are software that is installed
on the managed devices. The agent can able to
communicate with the manager. The agent can
record the management information about the
 The Management Information Base (MIB) is a
database which holds the information about all
network devices. Using this information, the
administrators can able to identify and isolate the
fault and also useful to monitor and manage the
network operations. MIB is a part of SNMP agent
software which kept the information about objects
such as variables. Each variable is assigned a unique
identifier that is called an object identifier (OID).
This information can also be accessed by agents. The
SNMP manager will be able to access the MIB
information for all the agents on the network.
MIB Objects:
MIB object defines the following groups of objects
indicate in Table 1.
Table 1: indicate MIB Objects
System
name, location, description
Interfaces
network interface statistics
(traffic)
IP
IP stats
ICMP
ICMP stats (error reporting)
TCP
TCP stats (TCP algorithms)
UDP
UDP stats
Each SNMP managed device keeps a list of variables
(objects), e.g. a router might have a variable called
buffer_overflow_count. The exact format and name
of these variables is standardized for a wide range of
network devices. Each object can represented using
a language called Abstract Syntax Notation (ASN.1).
The ASN.1 is a platform-independent language
which allows for object (variable) definition.
 The SNMP Protocol allows as reading and
writing and transferring the statistic information
about network devices. Each message is
transferred on internet using UDP. SNMP support
the TCP/IP protocol which is used to transfer the
agent’s queries and to make some changes in the
objects. The manager checks the state of the agent
through periodical polls using UDP and IP
protocol. It indicates the message flows in SNMP
protocol stack figure 3.
6. DESIGN
SNMP
AND
IMPLEMENTATION
OF
The organization plans to implement the SNMP
management, the organization need the following
requirements which indicate in Table 2.
Table 2: shows SNMP management requirements.
Manageable Network
Devices
Agents
Manager
Routers,
Servers,
switches, bridges, Hubs,
computer and printer
Agents are small software
modules that are manages
the devices
Network control center. It
works on UNIX or
Microsoft server
The organization’s complex development activities
required the cooperation of multiple business units in
different locations. All these organizations have
architected centrally to bring together to the same set
of applications. In this types of organization
structure, we can implement remote application
infrastructure which is a perfect solution for its user
which enable to access the network resources and
share the documents. Each organization has LAN and
WAN network. The network consists of network
devices such as computer, server, hub, switch and
routers. The organization has composed by various
departments. Most of the organization, the IT
department takes the responsibility to control the
organization networks. All the department network
devices are connected to the main server which is
monitored by the network administrator in the IT
department. Most of the organization is based on
client-server network. In the implementation to show
how effective NMS can help to solve network
problems before it occur. The NMS design of LAN
and WAN for the organization indicated in Figure 4.
Figure 3: SNMP protocol Stack
 The SNMP protocol uses well known port number
of UDP (161 and 162). SNMP runs on top of
UDP. The agent three request message is port
161. The manager for trap messages port is 162.
Because it works by exchanging a limited number
of types of message. The manager and agent can
be communicated using three types of messages
such as get, set and trap.
Figure 4: Organization Network Management
design of LAN and WAN
The SNMP protocol used to monitor and control the
network devices operate at application level, the
manager remains in a single location and use network
technology to communicate with network devices.
When the manager needs to interact with specific
network devices, the manager runs application
program act as client, and an application program on
the network device acts as server. The client
application that runs on the manager’s computer is
called a manager, and as server that runs on the
network device is called as agent.
SNMP agent is loaded on a computer with MIB
database. Then agent is configuring with SNMPs
Manager using specific SNMP commands. The
manager also configures to agent along with MIB to
send Traps or Notifications. SNMP agent receives a
request, and read the value of MIB variable, which is
specified in the list of variables, and the result of the
required value is sent back to the manager. The
manager can query each agent and get the
management data about the network devices which is
stored in the MIB. The agent can send unsolicited
information to the manager. Each device was
configured to report to a central NMS. The NMS
automatically discovers if any new network devices
are attached to the network. Manager queried each
device for its interface utilization and ping latency
statistics on regular basis. Figure 5 indicates result of
ping latency information across the network devices.
SNMP can collect the report about the CPU
utilization and also disk utilization which are
indicating in figure 7 and Figure 8.
Figure 7: CPU utilization reports provided by
SNMP.
Figure 8: Disk utilization reports provided by
SNMP.
The communication happens between manager and
agents using SNMP protocol. SNMP uses three types
of communication methods.
Figure 5: Display ping latency graph of different
network devices.
The SNMP is used to gather network devices
statistics and its configuration. SNMP is a
communication framework for all kinds of network
devices. Each device can receive and respond to
SNMP request or send its own traps. The central
monitoring server can able to analysis for the
behavior across the servers and network devices. As a
result, indicates in Figure 6. It is easily to find and
prevent the network problems because it can be
tracked to specific endpoints and behavior.
Figure 6: Display the analysis information of server
and network devices.
1. Request to do the Task
A manager requests an agent to provide certain
information about the managed devices. For example,
router will forward or receive the packets. It keeps
number of packer in the routing table. So the
manager can request to get this information to check
whether the router is congested or not.
2. Force to Do the Task
A manager forces an agent to perform some task by
resetting the agent’s variables. For example, an agent
regularly to checks the value of its reboot counter. If
the reboot counter is zero, it reboots itself. So the
manager can send a message to this agent to reset its
counter to zero. In this manner, the manager can
reboot the agent remotely.
3. Warning Message
An agent warns the manager of an unusual situation.
For example, Agent is a computer running an email
server. When it suddenly receives a very large
number of messages from a certain host in the
Internet, it sends a trap message to warn the manager.
7. IMPROVEMENTS IN PERFORMANCE OF
SNMP
Network monitoring system needs to be improve its
performance because of organization network may in
growth in size and complexity of MIBs according to
the requirements of the organization. There is a need
to improve the efficiency of the base protocol. The
performance can be increased by the following two
techniques.
1. Tipelining Algorithm
2. Parallel Algorithm
The Tipelining Algorithm invokes multiple threads of
GET NEXT operations within the manager targeted
at one agent. The agent processes each request which
is received from the manager. The manager does not
have to wait for the response to the preceding request
before firing off the next. The increase in efficiency
comes from the fact that the latency of the round-trip
delay is eliminated.
The Parallel Algorithm invokes group of the request
(threads) into single SNMP operations. This may
reduce the traffic flow and increase the process load
on the server. Most of the traffic flows are based on
round up time and timeouts, which are implemented
by both techniques, so it does not to overrun the
agent with request.
CONCLUSION
8. SNMP IN WAN (WIDE AREA NETWORK)
2. Douglas E Comer and Ralph E Droms “Computer
Networks
and
Internets
with
Internet
Applications”, 4th Ed, Prentice Hall.
When SNMP protocol implements over in wide area
network, the SNMP traffic can be slow down and
response time for the normal traffic also slowdown.
All the network devices are interrogated by the
SNMP protocol. So all the network devices do the
extra processing, for these reasons it is better not to
poll network devices more frequently. Sometime
when the organization needs to be implemented a
dedicated or point to point separate network
connection used to manage the network traffic. So it
does not delay the passage of data transfer.
9. SNMP STRENGTH
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Widespread popularity
Many standard MIBs available
Many products available
Network discovery
Analysis of the packets
Network device performance report
Configuration managements
Security aspects
Monitor
Test the connectivity and reach ability
Now a day the network monitoring system has grown
dramatically and reduced the administrator work
drastically by using SNMP. There are many benefits
the administrator will get such as monitoring the
performance of network devices, to detect, isolate
and recovery the fault from the network devices, to
gathering the statistic performance data, to control
network device remotely and also identify current
and future growth of the network for the
organization. The network administrator is also able
to control the time periods when users or groups can
access the network resources. The organization can
able to bring quickly each network device under
centralized management. Using NMS gives the
solution to network administrator to quickly
implement and distribute the change across the
network infrastructure. The result is great
improvement in the performance of network devices
in the organization.
REFERENCES
1. Behrouz A. Forouzan “Data Communication and
Networking”, 5th Ed, Tata McGraw Hills.
3. Andrew Tanenbaum, “Computer Networks”, 4th
Ed, Prentice Hall.
4. Larry L. Peterson S. Davie, “Computer Networks
A System Approach”, 4th Ed, Morgan Kaufmann.
5. Hossein Bidgoli, “The Handbook of Computer
Networks”, Volume-2, 5th Ed, Wiley.
6. Fred Halsall, “Computer Networking
Internet”, 5th Ed, Addison Wesley.
and
7. Curt M. White, “Data Communication and
Computer Networks: A Business User’s
Approach”, 7th Ed, Prentice Hall.
8. John Cowley, “Communications and Networking:
An Introduction”, 2007, Springer.
9. David Miller, “Data
Networks”, 3th Ed.
Communication
and
10. Jonathan Saperia, “SNMP at the Edge: Building
Effective
Service
Management
Systems”