Beginner’s Guide To Network Management

January 23, 2020 by Jose Miguel Poveda. banner


Network management is a service that uses a variety of protocols, tools, applications, and devices. It helps the company to monitor and control the proper functioning of IT resources. Due to the high cost of managing networks, before the ’80s, network management wasn’t widely spread among organizations. Nevertheless, in the last few decades, the quick development of networks and devices bring on new mechanisms to manage them correctly.

International standards, as the Simple Network Management Protocol (SNMP) and the Common Management Information Protocol (CMPI), help to create a network management system inside companies.


Network Management Architecture

Two key elements form a network management system: a manager and an agent.nThe manager is the link between the person who manages the network and the agent.To carry out this work, the manager has methods, human resources, and support tools. Due to the components, operating systems, and program interfaces involved, it’s critical to have protocols to provide an adequate connection.


OSI Model (Open System Interconnection)

OSI Model is the base for network management systems. This framework describes how devices and network applications should interact. The OSI Model has seven layers that show to the users what is happening in the network system. Let’s see each of them in detail.


Application Layer

It provides network services to the end-user. Those services work with network protocols to transfer data to the client. A compelling example of this is the HTTP protocol, commonly used by browsers and desk tools, such as Office, Outlook, or Skype. These programs offer services for the application layer to provide and receive data from the presentation layer.


Presentation Layer

The presentation layer is responsible for the transfer and formatting of data to the application layer. At the same time, it helps the application layer to get access to the session layer.


Session Layer 

Here is where devices connect. This layer enables users to establish sessions from different machines. When the session is ready, the data pass from or through the transport layer.


Transport Layer

This layer transmits data through network connections. It determines how much data to send, how to transfer it, where to take it, and the transmission speed. The TCP and UDP protocols provide a communication service between applications at the transport layer. Both control the transmission details and offer an abstraction of the network connection.


Network Layer

The network layer handles data switching and routing. It supplies the midpoints for network communication. This layer decides and administers the most efficient route for data transference within connections. The network layer functions through routers, firewalls, switches, and different devices. 


Data Link Layer

At the OSI Model, the data link layer is the most complex of all layers because it’s divided into two sublayers: Logical Link Control (LLC) and Media Access Control (MAC). This layer provides operative mechanisms to send data between network entities.  When data comes to the physical layer, the data link layer handles transmission errors, controls data flow, and provides a well-defined service interface to the network layer.

Therefore, from this layer, the information passes through the physical layer.


Physical Layer

At the OSI Model, this layer is also called the electrical layer. The physical layer is compounded by sockets, connectors, network cables, wireless radio frequencies, transistors, receivers, among other resources. When some network error occurs, this is the first layer that you should inspect. The reason is simple. In this layer, you can verify if a particular device is not connected or not working well.

The OSI Model layers have a mixture of network card drivers, operative systems, applications, and network hardware. That facilitates signal transmission over Ethernet, optical fiber, Wi-Fi, and wireless protocols.


Network Management Protocols

The network management protocols control how to transfer, receive, and route data packets.

Based on these communication rules, it-s possible to connect and share information between two devices.

All the network management protocols establish a specific architecture and processes to manage data. The most known protocols are SNMP and CMIP.

As an OSI Model protocol, CMIP came up as a substitute for the less sophisticated SNMP. Nevertheless, the CMIP protocol hasn’t been widely adopted. There are several reasons for this. Let’s see why.


SNMP (Simple Network Management Protocol)

A well-known protocol to manage networks. Companies build their network resources based on SNMP.
The Simple Network Management Protocol allows the manager to monitor the current state of network devices. Through that protocol, it’s possible to change the device’s configuration remotely.

SNMP was initially created for switches and routers, but it has been extended to a wide range of devices, such as Windows or Linux operating systems, printers, uninterruptible power supplies, among many others.

In SNMP, object identifiers (OIDs) determine the status of each network device. For example, OID lets you know what is the temperature of a sensor.

You can store the object identifiers of the SNMP protocol in a managed information base (MIB), which contains the structured information of all the parameters of a device within a network, which facilitates the understanding of what is being monitored.


SNMP Versions

Currently, it exists three versions for the SNMP protocol. Which one is the best? It’s hard to say. Let’s see why.

The third SNMP version is most secure than the other ones. It requires a user and password to access, and it also encrypts data.

These security improvements are important because through SNMP it is possible to modify and manipulate the device configurations.

Therefore, if an attack occurs, in versions one and two, it would be possible to control a device within the network, which would jeopardize the security of the service.

Although SNMP version three seems the best option, not all devices support it. Therefore, many companies still use previous versions. However, whenever possible, it is better to opt for the third.


CMIP (Common Management Information Service)

This is a network management protocol that is defined under the OSI model. Like the SMNP, the CMIP indicates how data should be exchanged between the manager and the agent.

The type of information that is shared in this protocol is based on the CMIS (Common Management Information Service), which defines the service interface to be implemented in the CMIP. That is, what services can be accessed to perform the management.

The services can be of three different types:

  • Notification services
  • Operation services
  • Association Services

Both protocols are based on the same idea of ​​exchanging messages between manager and agent to store relevant information in the MIB. However, they have some differences that must be taken into account.

On the one hand, SNMP is easier to implement. However, it has some security restrictions that make it less robust than CMIP. For that reason, it is recommended for low complexity network systems that do not require very detailed network management.

For its part, the CMIP has the advantage of being robust in its components, which is why it is more suitable for network systems with an extensive number of resources. Even so, its great disadvantage is the complexity involved in its implementation.

In short, the choice between one and the other will depend on the characteristics of each system and the resources it must monitor.

Now that you know the basics of network management, download a complete checklist for free to ensure that you are meeting all the requirements for monitoring your network.


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