In order to configure Communications Server to automatically locate clients within a network, the administrator first needs to either populate the location database with a network wiremap, or define an external database that already contains the correct mapping. As part of this process, the administrator validates the addresses defined in the location database against the Master Street Address Guide (MSAG) that is maintained by the E9-1-1 Service Provider. For more information, see Configure the Location Database.

When a Communications Server client logs on to the network, or changes networks, the client queries the Location Information Server for a location. The Location Information Server then matches network elements, such as a subnet, switch port, MAC address information and WIFI access points, to a physical location stored in the Location database. If the client is not located within a network defined in the Location Information Server, the administrator can require the Communications Server client to request a location from the user. The client stores this location, and includes it as part of an emergency call.

The Location information Server uses the following order of precedence to determine the client location:

1. BSSID
   
   
2. LLDP Switch/Port
   
   
3. LLDP Switch
   
   
4. Subnet
   
   
5. MAC
   
   

Note:
When a client connects to the network wirelessly, the Location Request determines the location using the WAP that the client is connected to. If the client is roaming, this may not be the closest WAP. We suggest that you append the location (such as a room number) with “Near” or “Close” to signify that the location is not exact.

If a client is located outside of the network, or within a subnet not included in the subnet table, and Location Required in the Location Policy is set to Yes or Disclaimer, the client will be prompt the user to manually enter a location. This location will be included as part of an emergency call.

Each manually entered location is mapped and stored to a local users table located on the client. When the client returns to any previously stored location, the client is automatically set to that location. A user can also manually select any location stored in the local users table. The locations stored in the local users table on the client are displayed as location history. A user can manage the history by updating existing locations and clearing all locations.

Note:
Updating older locations in history will overwrite the current location. For example, you are located at location1 and enter address1 into the client. You then move to location2 and enter address2 into the client. If you then try to update address1 while located at location2, the updated address1 will replace address2.