User manual

DEFINITY ECS Release 8.2 Maintenance for R8.2csi 555-233-119 Issue 1
April 2000
Maintenance for csi systems
1-137Troubleshooting Multimedia Call Handling (MMCH)
1
Calls Terminate with No Video
Description
Generally, loss of video can be divided into 2 types. The first occurs when the
DEFINITY MMCH switches to the endpoint, but nobody sees them. The receivers
see either “black” video or a frozen image of the previous speaker depending on
the codec of the manufacturer. The type occurs when the DEFINITY MMCH does
not switch to an endpoint.
Solution
In the first type described above, wiring problems, power to the camera, or video
encoder circuit pack problems in the codec are typical causes.
In the second type, no video from an endpoint typically occurs because it is not a
valid video source. This can be checked by looking at page 1 of the Status
Conference x Endpoint y Vid form under the Capability section. In this section, a
“y” or “c” suggests that the endpoint has video. An “e” means ept has not
declared any video capability in cap set, “n” is audio only, and “blank” means
audio add-on.
Also check page 1 of the Status Conference x Endpoint y Vs form for indication of
the video state for the endpoint values.
Calls Terminate Correctly but Are Unstable
Description
A number of conditions will lead to some or all endpoints having stability
problems during the course of a conference. A lack of stability from an endpoint
is noticeable by a lack of a video switching while the party is the only talker or
excessive disconnects from that endpoint.
Synchronization
Generally, the most common problem is a mismatch in synchronization sources
between the endpoint and the DEFINITY MMCH. This typically causes low-level
(Px64) handshake problems that can trigger the endpoint/MMCH to disconnect
the call. The MCCH’s timers are set to sufficiently high values so that, normally,
the endpoint will timeout and disconnect first. If installed in a customer network, it
is a good idea to perform an audit of the path synchronization is being supplied.
If there are different clock sources between endpoints and the DEFINITY MMCH,
some problems are sure to occur. The severity of these problems can range from
a handshake failure every few seconds to one per day. Depending on the type of
endpoint, this can cause the endpoint to disconnect or just freeze video until the
main problem is resolved.