Supporting VoIP Phones

When you install NetScaler Gateway as a standalone appliance and users connect with the NetScaler Gateway Plug-in, NetScaler Gateway supports two-way communication with Voice over IP (VoIP) softphones.

Real-time applications, such as voice and video, are implemented over User Datagram Protocol (UDP). Transmission Control Protocol (TCP) is not appropriate for real-time traffic due to the delay introduced by acknowledgments and retransmission of lost packets. It is more important to deliver packets in real time than to ensure that all packets are delivered. However, with any tunneling technology over TCP, such real-time performances cannot be met.

NetScaler Gateway supports the following VoIP softphones.

• Cisco Softphone
• Avaya IP Softphone

Secure tunneling is supported between the IP PBX and the softphone software running on the user device. To enable the VoIP traffic to traverse the secure tunnel, you must install the NetScaler Gateway Plug-in and one of the supported softphones on the same user device. When the VoIP traffic is sent over the secure tunnel, the following softphone features are supported:

• Outgoing calls that are placed from the IP softphone
• Incoming calls that are placed to the IP softphone
• Bidirectional voice traffic

Support for VoIP softphones is configured by using intranet IP addresses. You must configure an intranet IP address for each user. If you are using Cisco Softphone Communication, after configuring the intranet IP address and binding it to a user, no additional configuration is required. For more information about configuring an intranet IP address, see Configuring Address Pools.

If you enable split tunneling, create an intranet application and specify the Avaya Softphone application. In addition, you must enable transparent interception.