Troubleshooting Isdn-Pri - Avaya MCC1 Maintenance Procedures

When a downgrade does occur, information on the Status Conference screen indicates the success or
failure of the 64-kbps endpoints that are participants to properly rate adapt to 56 kbps. 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 56 kbps.
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 back to 64 kbps until every endpoint disconnects
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 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.

Troubleshooting ISDN-PRI

The following flow chart defines a layered approach when troubleshooting ISDN-PRI problems. Since a
problem at a lower layer affects upper layers, layers are investigated from low to high. In the flowchart,
the DS1 facility is layer 1, the ISDN-PRI D channel is layer 2 (S8100: TN765 Processor Interface), and
the ISDN trunks are layer 3. Transient problems are diagnosed on Page 2 of the flowchart. For problems
with PRI endpoints (wideband), see the following section.
Maintenance Procedures
December 2003
Troubleshooting
Troubleshooting ISDN-PRI
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