8.1.6 Network ConfigurationYou must evaluate the structure of the existing network to see if a VoIP network can be implemented. Beloware the points that should be evaluated.Is the IP network a managed network?A VoIP network should be implemented on a managed IP network such as Frame Relay, Leased Line, orIP-VPN (Virtual Private Network).An unmanaged network, such as the Internet (including an Internet VPN), cannot be used to employ a VoIPnetwork because delays and loss in data transmission can cause huge degradation in speech quality.Is it possible to have static IP addressing?IP telephones on the network always perform VoIP communications through the PBX. Therefore, the PBXmust be assigned static IP addresses, which must be programmed to each IP telephone on the network.NoteWhen the DHCP Server feature is disabled and external DHCP servers are not used, static IP addressingmust also be enabled for all IP telephones.Does only a single router provide access to the IP network?In a dual network, 2 routers provide access to the IP network as shown in the diagram below. However, onlyone router can be used as an access point to the network.Therefore, in the diagram below, if router A, whose IP address is assigned as the default gateway IP addressof the PBX and the IP telephones, fails, VoIP communications are no longer possible; they are not able toswitch their default gateway from router A to router B to access the IP network.IP NetworkRouter A Router BDefault gateway ofthe PBX: Router ADefault gateway ofthe IP Telephone:Router A308 Installation Manual8.1.6 Network Configuration
