VoIP over Internet can be unreliable and can result in poor quality calls, where the signal disappears and/or delays in carrying the signal mean that distortions to the transmitted sound are common.
To provide good quality VoIP services the infrastructure needs to be in place for very wide bandwidth IP provision. This will only be feasible with the UK's next generation phone and IP network.
Current costs to run multiple channels of VoIP outside companies with a Fibre optic network infrastructure are high. These networks still have difficulties when dialing outside the organization, and generally need to resort to PBXs which will interface to the ISDN phone system.
Because VoIP is an IP application, it is open to attack (unlike the PSTN system). We need to develop protection and security for VoIP systems.
