Explain the approach in troubleshooting a complex network infrastructure

In an organization the potential loss of revenue and reputation due to a network outage or a data breach (Chemweno et al, 2015), are driving enterprises to consider adopting a Network Maintenance Plan.
The main function of a Network Maintenance Model is to support the enterprise’s business needs which is accomplished by designing and developing processes and procedures which facilitate high availability whilst reducing the total cost of ownership (Ranjba, 2016).
Large networks are more complex in nature and therefore require a structured network maintenance approach which adheres to a predefined plan, unlike Small and Medium sized enterprises (SME) which deal with interrupt–driven network maintenance tasks as they happen on an ad hoc basis (Lacoste et al, 2015). Interrupt or Incident-driven tasks still form part of large networks but there are management processes and procedures in place to deal with these issues whilst reducing both interruptions and the impact on resources during the life-cycle of a network.

Introducing a network maintenance model assists in the design and creation of a method used to support procedures and processes in a structured maintenance plan. Methodologies include ITIL (IT Infrastructure Library), ISO’s FCAPS and others such as Telecommunication Management Network (TMN), Control Objectives for Information and related Technology (COBIT), Cisco Lifecycle Services and Microsoft Operations Framework 4.0.
A survey found that 62% of respondents have adopted or intended to adopt ITIL as their methodology of choice compared to 24% for ISO’s FCAPS (Sevcik et al, 2008) making ITIL the preferred model. ITIL is part of a framework in developing multiple processes to obtain ISO Accreditation but due to its complexity it usually needs to be outsourced during the initial design and configuration stage (England, 2009), whereas FCAPS emphasis is placed on technology, making it a simpler solution for an IT Department to adapt and implement as a foundation for their maintenance model.
In selecting a model, you must take into consideration the various elements that constitute the network as well as the business objectives and adapt the model to your environment or even create a hybrid solution to mould to your organizations requirements.

Irrespective of the methodology deployed there are tasks and procedures that are common to all businesses and by default should be embedded as part of an IT department’s basic duties. Lacoste et al (2015) and Ranjba (2016) outline the following common maintenance tasks that should be deployed regardless of the organization and as part of a management strategy: Routine and Scheduled Maintenance Tasks, Managing Network Changes, Network Documentation and Performance Monitoring alongside Restoration Operations in the event of hardware and data corruption.

A structured troubleshooting approach provides a step-by-step process that offers a reusable plan which aids in resolving issues in an efficient and effective manner (Lacoste et al, 2015).
The interrelationship between maintenance and troubleshooting suggests that the effectiveness of your troubleshooting efforts is directly linked to the structure of your maintenance plan as it overlays and complements these troubleshooting tasks as outlined below: Documentation, Baseline, Communication and Change Control.

Documentation and Baseline
Maintaining accurate and current network documentation is essential in quickly isolating problems on the network as outdated documentation may lead to the wrong conclusion and is often worse than having no documentation to hand. These documents should encompass a network diagram, a database holding all relevant details for each device, documents containing a list of the IP ranges and details explaining design options, both intra and interconnections details and also a copy of all device configurations.
Part of the documentation process is to establish a baseline of your network over period of time, this may be achieved manually or by instating tools and applications to monitor the different types of traffic, measure network performance and gather baseline performance statistics.

During each phase of a structured troubleshooting approach communication plays an important role as we traverse each step from defining a problem, information collection and analyzation progressing onto discarding of potential causes to entering the final phase of proposal and verification of assumptions for the problem to be resolved or escalated, with all these steps requiring clear communication.
To communicate in a succinct manner is essential as each step may be referred to a different department or escalated to a third party, as well as the possibility of multiple administrators being involved in the same case, plus clearly relaying and documenting the changes you have made is important.

Change Control
Network changes require authority to be granted before any modifications can be performed which helps minimise network downtime. The rules concerning the method and application of change requests during a specific window and how those changes are documented must be clearly laid out in a change management policy which will be incorporated into a Network Maintenance Methodology document.

Maintaining documentation, establishing baselines, change control management and communications are fundamental components of a troubleshooting process and enable faults to be quickly and efficiently identified and managed to a resolution. Consequently reducing the time spent in resolving network issues enables resources to be released for projects resulting in the lowering of network costs thereby increasing its visibility to the business, and making it easier to demonstrate its value to the group (Valiente et al, 2013). It makes sense to plan and implement troubleshooting activities as part of the overall network maintenance process as they are interwoven and complement each other.
A Structured Network Maintenance procedure needs to be implemented as part of a Business Continuity Plan, managed autonomously in a top-down approach. This approach places the responsibility on Upper or Senior Management involved in the Security Section to guide and support the IT Staff. It should not be the Network Administration Teams sole responsibility to implement a Structured Network Maintenance procedure as part of a Business Operation Plan (Stewart et al, 2012).

Chemweno, P., Pintelon, L., Van Horenbeek, A. and Muchiri, P.N. (2015) ‘Asset maintenance maturity model: structured guide to maintenance process maturity’, Int. J. Strategic Engineering Asset Management, Vol. 2, No. 2, pp.119–135.

England, R. (2011) ‘Basic Service Management’, Porirua, New Zealand: Two Hills Ltd.

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Lacoste, R., and Wallace, K. (2015) ‘CCNP Routing and Switching TSHOOT 300-135’, Indianapolis, Indiana: Cisco Press.

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Ranjbar, A. (2016) ‘Troubleshooting and Maintaining Cisco IP Networks (TSHOOT) Foundation Learning Guide’, Indianapolis, Indiana: Cisco Press.

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