DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Alarms, Errors, and Troubleshooting
5-63Multimedia Call Handling (MMCH)
5
Network Configuration Concerns with Synchronization
When auditing a network for synchronization, avoid unnecessary hops. Thus, a
switch providing star-configuration synchronizatio n is preferred over a
daisy-chain config uration. Additionally, if there are DEFINITY PBXs that have
EPNs, synchronization should be provid ed to sub nodes from the same p ort
network through which the PBX receives its synchronization. Passing
synchronization through the PBX Expansion Interface ad ds an unnecessary hop
to the path and creates another p otential point of failure.
Expansion Interface Duplication
If a customer’s network uses PBX EPNs with duplicated Expansi on Interfaces,
scheduled switc hing of the Expansion Interface links should be disabled on the
PBX via change system-parameters maintenance. When scheduled
maintenance runs and switc hes the links, there is a brief corruption of the d ata
path. If endpoints have ac tive calls when the switch oc curs, this corruption of the
data path causes Px64 handshake p roblems, which lead to the end points losing
video source status, and s ometimes disconnecting as described ab ove.
Disabling the EI switching is in the customer’s best interest to prevent the
disruption of the Px64 data stream. The customer will g et the same level of alarm
indications and main tenance on the EI links, regardless of the status of
scheduled switc hing.
PRI D-Channel Backup
A somewhat unlikely source of call stability problems occur where the
translations for PRI D-channel Backup betwee n two non-MCU switches were
incorrect. As an example, on switc h A, DS1 1A10 was designated as the primary
source, and on switch B, the c orresponding DS1 was desig nated as the
secondary source. When sched uled maintenance was run on the switch that had
an active standby D-c hannel, an audit disconnec ted some calls using the link .
The problem was corrected when the the D-channel primary/sec ondary
assignments matched.
Processor Duplication on the PBX
Do not enable the PI link switch on sched uled maintenance. This can cau se link
stability problems on the Accunet Bandwidth Controller (ABC).
Voice-Activated Switching Problems
Voice-activated switching on the DEFINITY MMCH does not follow the loudest
talker. The MMCH queues all speaking p arties and selects a new vid eo
broadcaster (the sec ond-oldest speaking party) when the oldest speaking party
has stopped talking . The new broadcaster will see the last sp eaker as its video.
The system can also “learn” ab out the noise coming from an endp oint to help
prevent false switches, adap ting both to noise level and repetitive sounds such
as a fan. This adaptation occ urs over approximately 10 second s.