Numeric transformations

IvozProvider is designed to provide service anywhere in the planet, not only the original country where the platform is installed.

A very important concept to achieve this goal is the numeric transformation, that adapts the different number format systems of the countries of the world defined in E.164 to a neutral format.

Note

Numeric transformation sets must be assigned to Carriers, DDI Providers, Clients and User endpoints (Users, Friends, retail accounts, residential devices, etc.) to define the way every entity talks with IvozProvider.

There are two different transformation scenarios:

Incoming transformations

When a new call is received in IvozProvider matching a provider that has been configured for peering, we must adapt the numbers that make reference to:

  • Origin of the call
  • Destination of the call

Depending on the country of the provider, the international numbers will have a format or another. In this case, the spanish provider will use, for example:

  • 00 + 33 + number belonging to France
  • It’s possible that the international numbers came without the 00 code.
  • It’s possible that, if the call comes from the same country that the provider, the number comes without the calling code (911234567 instead of 00 + 34 + 911234567 for Spain).

For an Ukranian provider, that doesn’t use the 00 as international code:

  • It will use 810 + 33 + number belonging to France.
  • It’s possible that even part of the international code (00 in most of the countries of the world) the provider use specific codes as prefix.

The goal of the incoming transformation is that, no matter what numeric system the provider uses, the number will end in a general and common format.

Important

This common format is usually called E.164 and shows the numbers without international code, but with country calling code: i.e. +34911234567

Outgoing transformations

In the same way the origin and destination must adapt incoming numbers, it will be required to adapt outgoing dialed numbers to properly work with each of the providers that will route our call.

For example, for a number with spanish number system:

  • Spanish provider: Destination will come in E164 (+34911234567) and for this provider, we can remove the calling code (will understand it belongs to its country), so the number sent to them will be 911234567.
  • French provider: The destination will come in E164 (+34911234567) and we must add the international code for France, so the number sent to them will be 0034911234567.

Note

To sum up, we aim to send the origin and destination in the format the provider is expecting.

Tip

Numeric transformation uses simple regular expressions to describe the changes done to the numbers. You can find multiple tutorials on net with the basic regular expression format.

Add a new transformation set

IvozProvider comes with an automatic transformation rules generator that fits with most of the countries.

In order to create a new set of transformations use Add Numeric transformations:

Name
Use to reference this numeric transformation set
Description
Additional information for each set
Automatic creation of rules
If set, Geographic Configuration fields will be used to automatically configure the rules of the set.
Geographic Configuration
International Code of the country, country code, trunk prefix if any, area code if any and national subscriber number length

Example for Spain

Fulfilling Geographic Configuration with:

  • International Code: 00
  • Country Code: +34
  • Trunk Prefix: <empty>
  • Area Code: <empty>
  • National number length: 9

Auto-created rules will transform the numbers for spanish providers that follow these rules:

  • A spanish number: Neither international nor calling code (34).
  • Not a spanish number: International code (00) and calling code (34).

Let’s check this set to understand what transformation rule does:

Attention

The automatic rule generation will create 8 common rules based on the given parameters. This rules can be edited later to match the provider requirements.

Spanish incoming transformation

Displayed in blue in the previous image:

  • Left called/destination
  • Right callee/origin

The same rules will be applied for the origin and destination:

  • The metric field will be used to order the rules (smaller first).

    • If a rule doesn’t match, the next rule is evaluated.
    • If a rule matches, no more rules are evaluated.
    • If no rule matches, no change is applied.

  • The Search field is evaluated against the number (depending of the transformation type it will be destination or origin).

  • The Replace field will use the capture groups that matched the Search field (displayed between brackets, 1 for the first one, 2 for the second one, and so on) to determine how the number will end.

Spanish outgoing transformation

Following the same logic, this 2 rules make the change of the outgoing external destination numbers.

Attention

To sum up: numeric transformation can adapt origin and destination numbers to E.164 for the platform, and to providers expected formats, based on regular expressions and metric that can be grouped in sets to be shared between multiple Carriers.

Conclusion

This is a key section that allows creating sets that will allow IvozProvider make needed numeric translations to ‘talk’ with all the external entities:

  • Providers (carriers and DDI Providers)
  • Client endpoints (Users, Friends, Retail accounts, Residential accounts, Wholesale clients)

Those sets will:

  • Convert custom external format to E.164 for internal usage.
  • Convert E.164 to custom external format for external usage.

Converted SIP headers:

  • Destination headers (R-URI/To/Refer-To)
  • Source headers (From/RPID/PAI/Diversion)

For all these transformations Regular Expressions knowledge is needed, unless automatic created rules work out of the box.