Purpose and content of a good Functional Design

I have been asked to outline the contents of a good Functional Design document and its minimum contents as a deliverable in a SharePoint implementation project and ofcourse we would like to have the best and best practices used in it when handed over by Vendor.

We currently have no Functional Design in this organization to use as a template FD, so I hope you can advise about the contents of a good Functional Design which can then be used as a starting point for the Technical Design.

I found something on the net, and I wanted to have your opinion whether this would be your typical Functional Design Document or not. Please give me your feedback:

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1. OVERVIEW
   1. Background      
   2. Document       Purpose

2. INFORMATION ARTEFACTS
   1. Artefacts       overview (the list of information pieces the system operates)
   2. Data Flow       (how data is moving across the system)
   3. Usage       cases (different scenarios of using information artefacts)
   4. Artefacts       Managing (describing how different products – sharepoint, SAP, drupal and       others) can manage artefacts)

3. INFORMATION ARCHITECTURE
   1. Site       Structure
        
      1. Site        Maps
   2. User       Interface and Branding
        
      1. Wireframes         
      2. Navigation         
      3. Branding       
   3. Content       Types, Columns and Lists
        
      1. Content        Types  
      2. Columns  
      3. List
4. LOGICAL      ARCHITECTURE
   1. Feature       Mapping (which features of the SharePoint  are gonna be used and for       which purposes)
   2. Farm       Logical Architecture
   3. Web       Applications
        
      1. Zones  
      2. Managed        Paths
   4. Site       Collections and Content Databases
   5. Shared       Services
   6. User       Profile and Properties
   7. Search
   8. Audiences      
   9. Service       Accounts
5. CAPACITY      PLANNING
6. PHYSICAL      ARCHITECTURE
   1. Server       Topology
   2. Network       Infrastructure
   3. Storage       Requirements
        
      1. Web        Front-End Servers  
      2. Application  Server  
      3. SQL        Server

I am a SharePoint Infrastructure Engineer, focussed on Administration and Installation of SharePoint Server environments.MCITP SP2010 Administration