I just started on an upgrade project, 3G-> 4G, with network flow documentation in PNG, BMP and Visio files (500+ flows). The HLD and LLD documents have been written however it appears from reading them that a lot of the drawings were not very accurate (out of date)/some look like they were made up and now we need to verify everything again.

What approach can I adopt to improving the network flow documentation so that our time is not spent just updating Visio and Word documents? From where it stands we may have to document from scratch.

I would like that the work I now do is reusable, updatable and well documented ensuring that the next Engineers who work on this can understand the history and the changes implemented.

Caution: This is NOT an open-ended question, please, I have a specific problem that I need to solve and I want a straight forward answer from those who have experienced this and solved it or have seen it being solved successfully - I do not need theories or opinions I need what works!

Edit: 2017/08/08 Seems I have to accept my own research as it did actually help me, but I was hoping someone would have shown something mind blowing too.

  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 8 '17 at 9:26
  • 1
    I figured that after four years, your answer had aged to perfection :)
    – Ron Maupin
    Aug 8 '17 at 14:00

I have been doing some research and prototyping on this now and found out here that this is something that I can share with you all as a reference if you also ever find this problem at your door step. I still welcome any advice or approaches that worked for you!

First of in order to maintain a reusable set of devices that are used over and over in the flows I got the immediate realisation that I did not want to copy and paste the Visio stencil object over and over and over again. Besides, I found another problem - I could not find the number of documents (configurations/deployments) that this device was used in without resulting to some sickening VB for Applications inside Visio or having a companion Excel/Access list of connections.

I really do not know if this is ever an issue for others but for an upgrade project it seems you can never underestimate where your device may be included in a flow. These changes have to strictly documented for all to see, not hidden in the ITSM (ITIL) Change Management tool! Especially as we do not have a front-end to this database to make meaningful investigations!

Being of UML decent, I have chosen to use a model repository to achieve this quest of sanity with our infrastructure and network documentation.

First, I have created a set of classes that represent every equipment involved in the documentation of our High Level Design (HLD) and Low Level Design(LLD). To me, this means that all engineers in the company have now a template of every asset we have on our network!

All changes documented with this model-driven approach enables us to can carry out the impact analysis, instantly!

  1. The single Model, has
    • 93 main devices, includes
      • WEB application servers,
      • GPRS and Mobile Internet Service appliances
      • DNS/Mail Relay servers
      • Routers
      • MPLS Routers
      • Proxies
      • Check Point Firewalls
      • Juniper Netscreen Firewalls
      • Intelligent Networks (IN) appliances
      • AAA/LDAP
      • Billing and Mediation appliance
      • Charging Gateway appliance

Devices with Operations Device Class List 2 Device Class List 1

  • The above were (re)used across the first set of 432 3G flows-paths (Stored in separate operation-specific model repository) where the devices are instantiated 168 times saving me all the Copy-Pasting and bringing me automatic dependency and usage analysis

Sample Flow Documented the UML Way Impact Analysis

  • 358+ VLANs/VRFS have been documented and can be easily applied to any network infra in the model

All this in 14 days working 12 hour shifts!

May be in future we should be able to integrate this model repository to asset databases like the Configuration Management Database. If anyone has ideas of something already done I would like to know. If you also managed to solve it differently and can reveal a glimpse please do.

Since the 93 devices are nothing secret, I am going to put them on GitHub and allow those with a UML tool to extend this base so that we could possibly have all the device groups that exist in the IT eco-system; pipe dream :]

It seems documentation is that most underdeveloped area in NE - my thesis is that if we had sufficient and valid documentation we could simulate a lot of the work we what to do without having to make the actual mistake, then ask how to fix it!

TODO: Add link to the GitHub repo...

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