A1 Numbering Plan Example Alternative40 Getting StartedA1 Numbering Plan Example AlternativeA1.1 Extension Number MethodThis section provides the numbering plan example using the Extension Number method, assupplementary information to the PBX Office Code method discussed in "1.2.2 NumberingPlan Example".IP Addressing InformationIP addressing information is typically supplied by a network administrator. Consult yournetwork administrator for specific values.PBX Numbering InformationPBX numbering information is necessary to setup phone numbers for a VoIP network.Configure the numbers conforming to existing PBX numbering systems.Los AngelsOfficeChicagoOfficeDescriptionUnit IPAddress 200.45.11.35 199.176.64.41The unit IP address identifies the location ofeach unit in the network during VoIPcommunications. A unique IP address mustbe assigned to each unit.Route IPAddress 200.45.11.1 199.176.64.1IP address of the primary gateway (typicallya router or similar device) that will beaccessed by each of the network units.Subnet MaskAddress 255.255.255.0 255.255.255.0Each network location has a subnet maskaddress that helps to define which digits ofan IP address are used for the networkaddress and the host address. Each unit IPaddress must fall within the same subnet asthat of the gateway (e.g., router) shared bythe units.Los AngelsOfficeChicagoOfficeDescriptionExtensionNumber 200 to 299 300 to 399 A number assigned to each extension.FaxExtensionNumber500 to 599 600 to 699 A number assigned to each fax extension.