Patton electronic SmartNode 4110 Series manual Procedure Configure the dejitter buffer, Adaptive

SmartWare Software Configuration Guide 47 • VoIP profile configuration

The operating modes for the dejitter buffer are illustrated in figure 4:

•Adaptive—The adaptive buffer automatically adapts to variations in the network’s delay characteristics and in general yields the best results for voice conversations.

In the adaptive dejitter buffer there are parameters that can be configured (such as shrink-speed, grow-step, etc.) that should not

be changed unless it is necessary to do so. An incorrect configura- IMPORTANT tion can lead to interoperability problems and loss of service.

Therefore, it is strongly recommended that only expe- rienced users change these parameters.

•Static—The static buffer is useful for voice conversations if you have specific information about your net- work’s delay characteristics (such as jitter period, etc.), so it should only be used by experienced users.

•Static-data—The static-data mode if you want to create a profile for fax or modem transmission without using the T.38 or fax bypass features described later in this chapter

Adaptive

max delay => max fill level

voice packets

Adaptive algorithm resizes buffersize up to max delay, depending on network traffic !

Fixed

max delay => buffersize

mean delay = max delay / 2

voice packets

Fixed algorithm sets buffersize to max delay. Generally mean delay of voice packets is max delay / 2

Figure 4. Adaptive versus static dejitter buffer

Procedure: Configure the dejitter buffer.

VoIP profile configuration task list 582