IP Office Technical Tip (Region: Global)

088: Windows XP SP2 PPTP VPN Clients and IP Office Phone Manager Pro

19th August 2005 - Full PDF Text Version


An issue has been noted when using VPN clients on Windows XP SP2 PCs. When directly connecting to a network without using VPN, both XP SP2 and XP SP1 work as expected.

However, when connecting to the network via VPN using a PPTP Windows client on Windows XP SP2 and 3.0(13) Phone Manager Pro, there is an issue with the quality of the audio path in one direction. The Phone Manager user connected via VPN to the customer’s network hears excellent voice quality. The other user hears an intermittently distorted audio path.

This problem does not occur when using Windows XP SP1.

In order to resolve this issue, the quality of service (QoS) packet scheduler on the XP SP2 PC must be uninstalled. Simply disabling the QoS packet scheduler does not resolve this issue.

To uninstall the packet scheduler, right click on ‘My Network Places’, and select properties. Select the network connection in question, then right click and select properties. Highlight the QoS Packet Scheduler and select the uninstall option.