Avaya DEFINITY Server CSI Maintenance Manual page 160

Maintenance for CSI systems
Rate Adaptation
Because of a lack of a clear explanation in standards, sometimes endpoints do
not work well with each other and the Avaya MultiVantage Software MMCH. The
MMCH will only allow a conference to downgrade from 64kbps to 56 kbps
operation on conferences that have the Rate Adaptation flag set to y.
When a downgrade does occur, information on the Status Conference screen
indicates the success or failure of the 64kbps-endpoints that are participants to
properly rate adapt to 56kbps. As a general indication that the conference has
rate adapted, the Conference Transfer Rate and Effective Transfer
Rate fields show initial and current transfer rates, respectively. For each 64-kbps
endpoint the column that indicates Rate Adapt shows an n if the endpoint did
not follow the procedures as specified by the H.221. If an endpoint shows y, it did
successfully rate adapt. If an endpoint shows c, it joined the conference at
56kbps.
Once the conference rate adapts, the endpoints that do not properly follow suit,
will become audio-only endpoints. A conference will not rate adapt from 56 kbps
back to 64 kbps until all endpoints disconnect from the conference and it idles.
The PictureTel 1000 Release 1.1C, PictureTel 6.01 software, and the Vistium 2.0
software successfully rate adapt with the MCU. External rate adaptation
techniques used by VTEL and CLI are known to cause problems with the endpoint
when used with this feature.
Endpoint or I-MUX in Loopback Mode
Some endpoints have a loopback enable feature. This makes Avaya MultiVantage
Software MMCH data loopback at the MMCH when a connection is in progress.
The loopback can be enabled prior to or during a connection.
The MMCH does not detect the loop and continues to VAS. In most scenarios, the
switch occurs, but within a few seconds, the broadcaster's return video becomes
its own image. Once the broadcaster stops speaking, the system "false" switches
to an apparently random port that was not speaking.
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Issue 5 October 2002
555-233-119