Lucent Technologies 555-233-119 Calls Terminate with No Video, Calls Terminate Correctly but Are Unstable

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 d ivided into 2 types. The first oc curs when the
DEFINITY MMCH switches to the endpoint, but nobod y sees them. The receivers
see either “black” video or a frozen image of t he previous speaker dep ending on
the codec of the manufac turer. The type occurs when the DEFINITY MMCH does
not switch to an endpoint.
Solution
In the first type describ ed above, wiring p roblems, power to the camera, or vid eo
encoder circuit pack problems i n the codec are typ ical causes.
In the second type, no vid eo from an endpoint typic ally occurs b ecause it is not a
valid video source. This c an be checked by looking at pa ge 1 of the Status
Conference x Endpoint y Vid form und er the Capability sec tion. In this section, a
“y” or “c” suggests that the end point has video. An “ e” means ept has not
declared any video capability in c ap set, “n” is aud io only, and “blank” mea ns
audio add-on.
Also check pag e 1 of the Status Conference x Endpoint y Vs form for indic ation of
the video state for the endp oint values.
Calls Terminate Correctly but Are Unstable
Description
A number of conditions will lead to some or all endp oints having stability
problems during the course of a conference. A lack of stability from an endp oint
is noticeable by a lac k of a video switching while the party is the only talker or
excessive disconnec ts from that endpoint.
Synchronization
Generally, the most common problem is a mismatc h in synchronization sources
between the endpoint and the DEFINITY MMCH. This typically causes low-level
(Px64) handshake problems that can tr igger the endp oint/MMCH to disconnec t
the call. The MCCH’s timers are set to sufficiently high values so that, no rmally,
the endpoint will timeout and disconnect first. If in stalled in a customer network, it
is a good idea to p erform an audit of the path sync hronization is being sup plied.
If there are different clock sources betwee n endpoints and the DEFINITY MMCH,
some problems are sure to occ ur. The severity of these problems can rang e from
a handshake failure every few second s to one per day. Depending on the type of
endpoint, this can c ause the endpoint to dis connect or just freeze video until th e
main problem is resolved.