The LCR (Least Cost Routing) module allows you to define routing rules for outgoing calls, ie to establish which gateway and therefore telephone line route a call. On the basis of the prefix, then, it is possible to define an entire class of numbers.
For example, the numbers starting with the prefix “0” are those of Italian landlines, the numbers starting with “3” will identify the mobile phones, and so on. For each prefix, it is possible to define a list of gateways that are queried in sequence according to the desired order.
The main prefixes that should never be missing in the configuration are:
1: emergency numbers (113, 115, 118, etc.)
8: green numbers
It is possible to associate one or more gateways to each of these prefixes according to the desired priority: for each call request outside the LCR will start to compare the prefix of the called number and when the comparison has a positive outcome, it will start to contact the list of the associated gateways. The comparison takes place between the prefixes that the LCR has in the list and the digits (starting from the left) of the called number. The comparison is successful when the LCR manages to find the longest prefix that matches the initial digits of the called number: for example, if the LCR contemplates the prefixes 3 and 347, the user who calls the number 3471112233 will use the gateways associated with the prefix 347, because this prefix “wins” in the comparison.
In this way it is also possible to adopt different rules for the same category of calls: for example, you can decide to call the generic cellphones (prefix 3) with a gateway and call the set of cell phones of the company RAM that start with the same number ( eg 32011223XX) with another gateway
|To add the first prefix select the Configurations – LCR menu and click on the link “… enter the first prefix”.
Enter the desired prefix and select the desired gateway from the list of gateways (it is necessary to have created at least one gateway, otherwise it will be possible to create them in this phase)
After entering, you can see the prefix and the gateway in the following screen:
|At this point, it is possible to add a new prefix (add prefix), and/or associate a new gateway with an existing prefix (add a gateway).
For example, if we add the prefix for calls to mobile phones (3), and associating it in two phases both to a GSM gateway and then to an ISDN gateway, we will see the situation here on the side
The order in which the gateways are queried is the one in which they are displayed (the first gateway contacted for a particular prefix is the one above). This order can be modified by dragging (drag & drop) the gateway above or below the others. From this section, it is also possible to deactivate and reactivate the gateways by clicking on the ball to the left of the name. The green dot indicates that the gateway is active, the red dot indicates that it is deactivated.
NOTE: disabling a gateway will affect all the rules where the gateway appears: so be very careful to use this function.
Furthermore, it is possible to remove the association of a gateway from a prefix, or even delete the internal prefix, cancelling it with the button.
NOTE: the creation of the prefixes and the modification of the query priorities of the gateways will affect the set of explicit outbound (external) routing rules for the details of which please refer to the relevant section.