LifeSize Gateway-PRI, User Manual

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74 LifeSize Gateway User Guide
Configuring Gateway Settings
G.728 and G.711 takes place, the audio bandwidth usage is compressed to 16
Kbps. This provides an additional 40 Kbps of bandwidth to the existing video
bit rate on the ISDN network, contributing to improved video quality.
Note
The LifeSize Gateway automatically performs A-Law G.711-to-µ-Law
G.711 translation between the IP and ISDN sides if needed.
You can configure the LifeSize Gateway to prioritize the transcoding, giving
preference to a particular codec that is applied to calls, thus optimizing the
resource allocation utilized by each call.
A
BOUT
T.120 D
ATA
C
OLLABORATION
S
UPPORT
The LifeSize Gateway provides full end-to-end support for T.120 data
collaboration sessions, provided all terminals support the T.120 standard in their
conferencing applications. In video calls with data transfer, the LifeSize
Gateway accepts whatever bandwidth the ISDN connection defines for the data
and dynamically adjusts the outgoing bandwidth used for data by using the
MLP, HMLP and VarMLP formats.
If transcoding or T.120 capabilities are required, the LifeSize Gateway has to
reserve resources for these. The LifeSize Gateway can differentiate between
those calls that support T.120 and those that do not. When receiving calls, the
LifeSize Gateway can check whether you are reserving resources for
transcoding or for T.120 capabilities.
The LifeSize Gateway enables the user to determine the trade-off between the
number of non-T.120 calls that the LifeSize Gateway can support and the
number of calls sent with T.120 capabilities. The total number of calls that the
LifeSize Gateway can support is accordingly reduced by this reallocation of
resources.
The H.320 standard defines space allocation within a call. The H.320 standard
defines the logic for bit rate allocation among audio, video and data channels in
the context of the overall bit rate of a call. If you work with T.120, reallocation
of bandwidth is always at the expense of available video resources. The
requirements of the H.320 standard govern this reallocation—it is not
configured in the LifeSize Gateway. The LifeSize Gateway simply decides
whether or not to send T.120 capabilities. You configure T.120 capabilities in the
Advanced section of the LifeSize Gateway interface Settings tab.