structures here, and you've got the good luck to be talking to someone trained and experienced in both - I started on the accounting track years ago and shifted to IT. The basics for both are the same.
Your organisational structure should be large enough and flexible enough to allow for a major expansion of both nodes and people within a node and sub nodes. This is to allow for new units at all levels and more staff in all units. This applies to the IT structure and the accounting structure.
The system should be capable of allowing for quick and easy cross reference at unit and operational level. Especially the accounting side should allow for the easy identification and comparison of similar type operations across the organisation. For example, the operations of the administration unit in company A should be easily comparable with the administration unit of company B and company C, etc.
Accounting
From an accounting perspective the chart of accounts should be well broken up, in line with the standard chart of accounts. thus, and cost code should have the following identifiers:
Corporation - Company - Geographical Unit - Operational Unit - Activity Unit. It should also have auxiliary codes to break it down to expenditure activity types, like - admin, client, cross charge unit, overhead, utilities, etc.
All this is to allow quick and easy identification and accumulation of expenses and income for analysis in a range of manners.
One organisation I worked in had a need to identify 5 corporations - 300 companies - about 6,000 units - 90,000 sub unit - 500 activities available across all sub units; then split into the need to allow for cross charging between units and expense / revenue codes. Luckily, the figures above are the totals for each level, so when you looked at things it kind of averaged out as 1 - 6 - 20 - 15 - and most only used between 20 to 80 activities per sub unit. Thus you didn't need everything for each organisational unit, but the codes were such you COULD use any code for any unit, once it was activated. So, a transfer of operations between units at any level was easily done by changing the code or codes for the higher levels and activating the codes for that grouping.
But, most of that is accounting and any half trained accountant should be taking that into account. What's important is to include the extra codes to allow for cross charging identifies for two to five levels below the activity code.
I could go on further, but this is NOT the place for a ten thousand word detailed briefing paper on the proper handling of Activity Based Costing accounting and management.
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Now moving over to the IT network side, your organisational structure must also break down into your network addresses, and allow for easy identification and expansion there as well. This is important with the assignment of the internal IP addresses, and you need to ensure you use a class that suits for expansion for some years to come. Some small organisations that have only a few people and don't expect to go to more than 50 people over the next several years could get by with a class C address group like 192.168.1.x - while a huge organisation would need a class A group like 10.x.x.x and most will get by with a class B group like 172.1.x.x.
As with a chart of accounts, you break up the same way by assigning company - division - branch - unit codes within the IP address. This can be done in a number of ways, and will depend upon how big you expect the organisation to grow. For example, using a class A group each company can have a different number for the second digit so you get 10.1.x.x and 10.2.x.x for two different companies within the corporation. And further breakdowns occur and the next point of 10.1.1.x and 10.1.2.x etc. Another option may be to assign numbers within a group, so the first company may be 172.1.100.x and the second is 172.1.200.x etc. Whichever you use, you need to analyse the organisation and its probably expansion process for the next several years.
The principles applied in this analysis is the same for a network as for a chart of accounts, just the depth varies.
To give an example of how a network can be laid out to show the corporate structure via IP address, I've one on display at:
www.bywater.net.au
select the business site, select Networking, and click on the network plan shown on that page.