Cisco have a process for this, it’s call PPDIOO (most people call it Pid-i-o), it has six phases and can be translated into most IT projects, it’s what the CDDA, CCNP (Design) and CCDE certification are based on, it’s tried, tested, works very well and hopefully will give you a nudge in the direction you need.
The six steps, Prepare, Plan, Design, Implement, Operate, Optimize.
Prepare – Establish business/compliance requirements need to be met and determine return on investment, consider future requirements, this will help you argue a decent budget. Creation a High Level Design (HLD).
Plan – Evaluate the organisations current network status, technology deployed and consider any governance/compliance and customer contractual provisions. Consider what the environment will be used for, how it will be used and by who and how, consider the products out there, don’t just use the same products you’re familiar with ‘as they work’, choose the best product going forward (it may be what you are currently using), especially if there is expected growth of the numbers of users and therefore an increase in the use of services, applications and additional (unknown) function. Create a test plan.
Design – Identify your organisations technology goals and deliverables (what your colleagues actually do), applications to support etc. required to meet all the expected availability, reliability, security, scalability and performance metrics identified in the plan.
Implement – installing changes without disrupting the existing network or creating vulnerabilities. Follow the test plan created in the planning stage, does it meet the requirements? If not, why not? Bad design? Wrong planned products?
Operate – Fault detection, correction, and performance monitoring, BAU.
Optimize – Identify issues affecting expected design goals and prepare to plan a design to implement a change you can operate…etc.
So, you have your requirements, consider what changes you need, the design phase is crucial, this is where you need to identify how you want the back up stuff to work and how. This will depend upon all the requirements as a whole.
I appreciate I haven’t given you exact ideas, but hopefully the above will provide you with a bit of direction and some ideas but please don’t do something as it will work. In years of network design I can tell you that when you hear designers say ‘that’ll work’ you hear those supporting the environment saying ‘We have a work around for that’. Workarounds are never, ever good and should be avoided at all costs.
