MX-ONE with Branch Offices in the Same Area Code

Description

This scenario consists of a main office MX-ONE with branch offices located in the same PSTN area, see Figure 1. All the IP telephones which belong to a branch office have their own domain (that is, madrid1.es", "madrid2.es", and "madrid3.es"). The main office has a route to the PSTN (that is, route 63) and a public external destination (that is, 00) to access that route.

The access to the PSTN from the branch offices is carried out through the main office public trunk.

Note: Although each branch office usually has an SBN installed for survivability, it has not been considered in this scenario, for illustrative purposes.

It is required to enable the 112 emergency calls in the main office and in the branches, where the following emergency number formats must be valid:

Emergency number (that is, 112)
Route access code to the PSTN + emergency number (that is, 00112)

The emergency calls must be enabled for logged-on and logged-off IP telephones, and it is also required that the emergency center can dial back to the calling user. In this case the emergency center uses the received calling number in the emergency call to dial back to the caller.

Figure 1. Main Site with Branch Offices in the Same PSTN Area

Prerequisites

The same prerequisites as in the scenario without branch offices apply here (see Prerequisites).

Execution

The same execution steps as in the scenario without branch offices apply here (see Execution).

Verification

These considerations should be taken into account:

Avoid using the live emergency number when testing.
When making a final test call to the emergency number, be careful to check the local regulations.

After the execution phase the following configuration is obtained, see the following figure.

Figure 2. Configuration after initiation of data to support Emergency Calls

To verify the new configuration for emergency calls, the following actions can be done.

Emergency Calls from Logged-On IP Telephones located in the Main Office:

Dial the 112 emergency number from a logged-on IP telephone and check that the emergency center is called.
Dial the 00112 emergency number from a logged-on IP telephone and check that the emergency center is called.
Dial the received calling party number in the emergency center and check that the calling user is dialed back.

Emergency Calls from Logged-Off IP Telephones Located in the Main Office:

Dial the 112 emergency number from a logged-off IP telephone and check that the emergency center is called.
Dial the 00112 emergency number from a logged-off IP telephone and check that the emergency center is called.
Dial the received calling party number in the emergency center and check that the calling user is dialed back.

Emergency Calls from Logged-On IP Telephones Located in a Branch Office:

Dial the 112 emergency number from a logged-on IP telephone and check that the emergency center is called.
Dial the 00112 emergency number from a logged-on IP telephone and check that the emergency center is called.
Dial the received calling party number in the emergency center and check that the calling user is dialed back.
Repeat the steps in every branch office.

Emergency Calls from Logged-Off IP Telephones Located in a Branch Office:

Dial the 112 emergency number from a logged-off IP telephone and check that the emergency center is called.
Dial the 00112 emergency number from a logged-off IP telephone and check that the emergency center is called.
Dial the received calling party number in the emergency center and check that the calling user is dialed back.
Repeat the steps in every branch office.

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