In numbering plan, area code allocation in one country can do with two ways, which is random or systematic technique. On random technique, area code numbering can apply without follow a rule or random and is not bind on available network form. Meanwhile on systematic technique, numbering can apply with rule that already decided and bind on condition or available network form. For more understanding different between both techniques, this explained characteristic from each technique on area code numbering plan:
Random technique:
- Numbering can apply with randomly
- No need of backup numbering
- Not bind on network form (mash network or star isn’t problem)
- Because factor on (b) and (c) up, then area code numbers plan become easy. Hard to implement.
Figure 4.3 Example randomly area code allocation
The random numbering seems easy. The hard way is implementation because there is possibility that the locations with short numbering area code actually have a long distance geographic (Example city A and B, E and F), on the other hand areas with area code that far from another number actually geographically is closer. So that, register equipment to shaped long distance network must first receive all digit or area code information in order to confirm where the truly destination connection long distance that will do. Off course, this condition will influence speed of routing process and for calculate charging will needed equipment that more complex.
Systematic Technique:
- Numbering bind on rules that already confirmed, especially on network form
- Need to think and planed backup numbers for possibility of network development, so that on the planning become more difficult and more carefully.
- Because the plan is already planed accurately, then on technical execution will become easy.
Example area code numbering allocation with systematic technique represented by figure 4.4, which showed that every digit from area code number already contain information about destination area so that will to simplify preparation routing process. In this case, numbering area code allocating plan bind on network that hierarchic formed.
Figure 4.4. Area code allocation systematically
Example of country that applies numbering area code with systematic technique is Indonesia, although on development actually combined with numbering random technique. But because at this moment almost for the greater part of central that operate in Indonesia is digital central, then numbering allocation with random technique not anymore become a problem.a
