Introduction
Network management refers to the activities, methods, procedures, and tools that pertain to the operation, administration, maintenance, and provisioning of networked systems.
This includes managing computer networks through a wide variety of software and hardware products that help a network system administrator manage a network.
Core Responsibilities of a network manager
- Operation: The network manager is responsible for keeping the network running smoothly, monitoring the network to identify problems that may occur.
- Administration: The network manager monitors the network resources and how they are utilized eliminating bottlenecks in the network. It is the responsibility of the network manager to ensure that the network is protected against unauthorized users.
- Maintenance: Maintenance is concerned with performing of repairs on available equipments and the upgrading of the network resources. It also involves both corrective and preventive measures to make the managed network run effectively and efficiently. The network manager should oversee these duties.
- Provisioning: This involves configuring network resources to provide specific services such as voice services. The network manager should make sure that the network is configured correctly for different services.
- Coordination: The network manager coordinates all the network resources including the staff and the management tools.
The five key management tasks
- Planning: The process that develops, creates, and implements strategies for the accomplishment of objectives is called planning. The general approach to planning begins with the creation of strategic plans for the entire network. To better understand the planning process, an organization must thoroughly define its goals and objectives. The network management team must have clear goals and objectives to meet the network needs of an organization.
- Organizing: The principle of management dedicated to the structuring of resources to support the accomplishment of objectives. Organizing tasks requires determining what is to be done, in what order, by whom, by which methods, and according to what timeline.
- Directing: The network manager should be able to delegate the staff to perform various duties to ensure that the network is running properly.
- Controlling: Monitoring progress toward completion, and making necessary adjustments to achieve the desired objectives, requires the exercise of control. In general, the control function serves to assure the organization of the validity of the plan. The controlling function also determines what must be monitored as well as applies specific control tools to gather and evaluate information.
- Staffing: People are the most critical link any management department. it is imperative that managers continuously recognize the crucial role that people play in the network management.
Discussion of network management tools use
Network management is an area of information technology in which many tools, applications and devices are used to monitor and maintain a network.
The network management architectures have the basic structure and a set of relationships. In simple terms, in a network management, workstations send alerts when they encounter any problems to the management entities. These management entities react to that alert by logging the event, notifying the operator, shutting down the system or automatically trying to clear the fault that has occurred.
The management entities also poll the workstations or end systems to check periodically whether they are running properly. The network management protocol is used to send and receive information to and from the managed devices.
The most common protocol that is used in network management is the Simple Network Management Protocol (SNMP) and the Common Management Information Protocol (CMIP).
For the purpose of this assignment I have divided the network management tools according to the five conceptual areas of the network management model namely the configuration, fault, security, performance and security management modules.
Due to needs that have arisen in network management I have also added the protocol, bandwidth and inventory management tools.
- Configuration management tools: Configuration management tools are used for tracking the hardware and software versions of resources that are on the network to identify their effects on the network’s operation. System and Configuration Management for LAN’s, servers, workstations, telecom and devices An example of this is Microsoft’s System Management Server (SMS) which has the capability to monitor, manage and track every piece of software and hardware on a given network. Another example of this is the ISDNwatch which is a graphical monitor, logging tool and early warning system for ISDN routers.
- Fault management tools: The purpose of this network management tools is to detect, log and alert the system administrators of problems that might affect the systems operations. Usually the symptoms of the fault are identified and the system that is generating the fault is isolated so that it does not affect the other systems and the production in the company
- Security management tools: This is used to control the access to the network based on the guidelines or rules provided. Security Management deals with controlling access to resources and even alerting the proper authorities when certain resources are accessed. Network management systems can be used to send messages when certain files, servers or routers are accessed. Intrusion detection systems such as Symantec’s Intruder Alert have this security management capability. The ipMONITOR is another such tool.
- Performance management tools: Performance management deals with monitoring, assessing, and adjusting the available bandwidth and network resource usage in order to efficiently run a network. Performance management is a very important part of the network management model particularly to an organization that wants to streamline their network’s performance. Solar Winds is a great tool for performance management.
- Accounting management tools: The network accounting tools are used to measure the network utilization parameters in such way that the users of the network are regulated properly. Such regulations lead to optimal utilization of the network resources which also plays a role in the performance management. Accounting management monitors and assesses the usage of data and/or resources for the purpose of billing. This aspect of the network management is done by Internet Service Providers to bill customers for the resources they use.
- Protocol management tools: The protocol analysis tools are used as their name suggests; analyzing local area Networks and wide area Network Protocols.
- Bandwidth management tools: Dynamically control the bandwidth usage, define and manage unlimited service levels, and monitor access services in real-time, while gathering historical data for analysis. Examples of these tools are Dyband , Entuity Eye of the Storm (EYE) and paessler PRTG which is a windows network traffic monitor that will monitor bandwidth usage and other network parameters via SNMP.
- Inventory software tools: These are software tools used by the Help Desk for the purpose of keeping of inventory of computers in a network.
Case Study Of the Arpanet Crash Of 1980
Case Problem
On October 27, 1980, there was an unusual occurrence on the ARPANET. For a period of several hours, the network appeared to be unusable, due to what was later diagnosed as a high priority software process running out of control devouring resources needed by other processes, thereby making the network unusable.
The ARPANET lost all connectivity for four hours. The entire ARPANET went down in the following way: the status messages sent back and forth between nodes were deleted if the time stamps were older (smaller) than a previous message. Connections which already existed were summarily broken. No IMP was able to communicate reliably with any other IMP.
This faulty sequence of control packets in turn affected the apportionment of software resources in the IMPs, causing one of the IMP processes to use an excessive amount of resources, to the detriment of other IMP processes.
Cause of the crash
The immediate cause of the problem was a hardware malfunction which caused a faulty sequence of network control packets to be generated. This was due to a bit corruption in a memory node, three six-bit time stamps were each kept (none being deleted) because they each happened to be larger than their predecessor message (modulo 64).
Each of these three messages caused other messages to be sent over and over to other neighboring nodes who kept these sent messages. Close inspection showed that all the updates were from a single IMP, IMP 50. It was unable to communicate properly with the neighboring IMP29. Not only were all the updates on the queue from IMP 50, but they all had one of three sequence numbers (either 8, 40, or 44)
For simplicity, 32 was considered a permissible difference, with the numerically larger time stamp being arbitrarily deemed the more recent in that case. In the situation that caused the collapse, the correct version of the time stamp was 44 [101100 in binary], whereas the bit-dropped versions had time stamps 40 [101000] and 8 [001000]. The garbage-collection algorithm noted that 44 was more recent than 30, which in turn was more recent than 8, which in turn was more recent than 44 (modulo 64). Thus all three versions of that status message had to be kept.
How the network was restored
All that was necessary was to patch the IMPs to disregard any updates from IMP 50, which after all was down anyway. In summary, each node had to be manually shut down.
This procedure was fully successful in bringing the network back up.
How could this problem have been avoided if the ARPAnet managers had today’s management tools?
Today there are numerous network management tools that help network managers monitor the network resources and the processes that occur at any given time. I will use the examples of some of the management tools that I discussed in PART 3 of this assignment and the modifications that could have been made to ARPAnet network design at that time.
- Firstly, situation like this could have been avoided if there was proper checksumming of dropped bits and the table logs. However there is potential drawbacks of using a lot of CPU cycles and taking up of memory space which are scarce resources.
- Use of upgraded IMP hardware
- Design a system whereby all the IMPs go into their loader/dumpers when the problem arose. This would have enabled the re-initialization and restart of all the IMPs much quickly.
- Use of configuration management tools such as the ISDNwatch that would have alerted the network administrators of device failure in their resources and in this case the routers.
- Use of fault management tools which detect, log and alert the system administrators of problems that might affect the systems operations. This would have enabled the administrators to isolate and deal with the problem on time.
- Use of efficient built in alarm system that could have alerted the administrators that there was a network outage. Again, this could have limited the amount of time that there was this outage.
- Bandwidth management tools could have controlled the rate at which the updates were being generated and built analysis data thereby reducing excessive demands on the system.
Application of the key management tasks to the Case
- Planning: The ARPAnet managers should have had strategic plans for the entire network such that when this kind of a problem occurred it would have been easier for them to pinpoint what the cause of this problem was.
- Organizing: Organizing tasks requires determining what is to be done, in what order, by whom, by which methods, and according to what timeline. The network manager should have determined who should have handled this problem and by which methods
- Directing: The network manager should be able to delegate the staff to perform various duties to ensure that the network is running properly. There should have been a staff member to monitor the network.
- Controlling: The controlling function also determines what must be monitored as well as applies specific control tools to gather and evaluate information. The network manager should have determined what was to be monitored to ensure that there was no network outage and by which tools
- Staffing: The manager should have that there was enough staff to deal with the situation when it arose to limit the time of the outage.
References
“The New Routing Algorithm for the ARPANET,” IEEE TRANSACTIONS ON COMMUNICATIONS, May 1980, J.M. McQuillan, I. Richer, E.C. Rosen.
“The Updating Protocol of ARPANET’s New Routing Algorithm,” COMPUTER NETWORKS, 1980, E.C. Rosen.