Number Manipulation

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Number Manipulation is used to change number formats.

Main RULES

MOR works with numbers that are in E.164 format.

That is, numbers coming to MOR SHOULD BE in E.164 format. Numbers leaving MOR ARE in E.164 format.

From this, the actions below follow: 

1. The incoming destination number should be converted to E.164 (done by Localization)

2. The outgoing number may be made out of an E.164 number (done by Provider Rules)



Definitions

  • E.164 format - In short, it's the number without an international prefix that starts with a country code. For more details, check Wikipedia.
  • Localization
    • The main idea of Localization: No matter how the user dials the number (destination), when localized it should be in E.164 format.
    • Localization has nothing in common with numbers you send to providers. It operates with numbers received from the caller.
  • Provider Rules
    • MOR operates with numbers in E.164 format, but the provider often asks for a differently formated number - so Provider Rules formats the E.164 number to a provider-acceptable format.



How Number Manipulation works

The first part, which makes any incoming number E.164 compatible, is done by Localization. The second part, which changes the E.164 number, is Provider Rules. The basic schema for this process can be simplified as:

Number manipulation logic.png


MOR works only with E.164 numbers. That means, MOR accepts only standard numbers. If a number is not in E.164, it must be changed to an E.164-compatible number.

For this task, MOR has a feature, Localization (found in Billing -> Functions -> Localization), for "standardizing non E.164 numbers to correct E.164 numbers".

If requested by an outgoing calls provider, MOR can cut/add a special prefix to the number to send it to the provider in its requested format. This can be done using Provider Rules.

Localization and Provider Rules follow the same logic.

An example of how Localization works: 

Number from Caller -> Localization -> Number from Caller in E.164 format -> MOR -> Provider Rules -> Number for Callee.


  • International prefixes and local number formats are handled by Localization.
  • Provider technical prefixes and special number formats for providers are handled by Provider Rules.

This means:

  • if MOR receives a number with an international prefix, you need to strip it and make the number E.164 compatible.
  • if MOR receives a number in some local number format with some special digit(s) in front of it you need to strip it, add the country code -> make it E.164 compatible using Localization
  • if your provider requests some fancy technical prefix, you need to add this prefix using Provider Rules. Add the prefix to the E.164 number. You may need to cut some digits (let's say the country code) before adding the technical prefix. Do this with Provider Rules.

Let's repeat, because it is extremely important: 

When MOR receives a number, make sure it is E.164 compatible or make it E.164 compatible with Localization.
When you are sending a number to a provider, use Provider Rules to change the E.164 number to the format the provider expects.



Work flow to set up Localization and Provider Rules

To set up correct Localization and Provider Rules, you need to do the following:

  1. Know what number format the user will be dialing.
  2. Create an appropriate Location and assign the user to that Location.
  3. Create rules for the specific Location to handle user-entered numbers.
  4. Know what number provider expects.
  5. Create rules for the provider which handle the number transformation to provider's expected number.

For training, let's cover the full example using the scheme we had before:

Number manipulation logic.png

  1. The user dials a number: 863042438.
  2. The number is made E.164 compatible by Localization: we cut 86 and add 3706 to get 37063042438.
  3. Billing: MOR uses 37063042438 to find the correct destination and rates.
  4. An E.164 number is transformed to the provider format by Provider Rules: number 37063042438 is transformed to a number format that the provider expects by adding 89765#, so we have: 89765#37063042438.
  5. The call is sent to the provider as: 89765#37063042438.


HINT: We should remind you to use Call Tracing to debug all this.

HINT: World Telephone Numbering Guide can help a lot in handling different number formats.



Rule Ordering

Rules for Localization and for Provider Rules take the following order:

  • Device/Provider Location.
  • Global Location.

This means that Global location rules are applied to every device, but have a lower priority over some specific Locations. That means - if a device belongs to Location X, then rules in Location X are reviewed first. If none of the rules can be applied from Location X, then rules in Location Global are checked.

Once one rule is applied, no further rules will be applied subsequently.



How an exact rule for a dialed number is selected from many rules

How does MOR select a rule which should be applied to the number?

Three steps are taken for all rules (for Localization & Provider Rules).

1. MOR checks for number length and rejects these rules if the dialed number's length does not fall into the described intervals of MIN and MAX, e.g. the number's length is less than MIN or greater than MAX.

2. Next, these rules are rejected if the beginning of the number does not match the Cut value of these rules.

3. In the last step, MOR selects the rule that has longest Cut length.

For example, the rule selected at step 3 will be used to transform the dialed number.



Example

Let's say 012337068111543 comes from a caller to the MOR system.

We have the following rules: 

#  CUT  ADD  MIN  MAX
1  01   11   11   14
2  012  22   12   15
3  123  33   15   16
4  0123 44   11   20

1. MOR checks the number length by the available min/max settings. So if the incoming number's length (number length = 15 in our example) is more than or equal to MIN and less than or equal to MAX, this rule will not be rejected. The rule will be rejected if the number length is less than MIN or greater than MAX.

We reject rule #1 because 15 is > MAX(14). After the first step, we have: 

#  CUT  ADD  MIN  MAX
2  012  22   12   15
3  123  33   15   16
4  0123 44   11   20

2. MOR checks for all remaining rules which haven't been rejected by the first and second rule, and selects the rule which has the longest CUT. 

#  CUT  ADD  MIN  MAX
3  123  33   15   16
4  0123 44   11   20

3. MOR proceeds to look for the CUT value which match the beginning of dialed number. MOR rejects all rules which do not match the beginning of the dialed number.

In this step, we reject rule #3, because its CUT value (123) is NOT the beginning of dialed number: 012337068111543.

After the second step, we have:


This step selects the rule with the longest CUT, so our result is: 

#  CUT  ADD  MIN  MAX
4  0123 44   11   20

4. This rule is applied to the dialed number. For example, if the dialed number is 012337068111543, we first cut the CUT value (0123) from it (giving us 37068111543) and then we add the ADD value (44), so that the final result is 4437068111543.




See also

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