Chapter 18 Maintenance and Troubleshooting
Resolving problems
SmartClass TPS User’s Guide
June 2014 22035456, Rev 001 153
If this is the case, do the following.
– Verify that you specified the “Proxy” on the Proxy Settings menu as the outbound proxy, or the
device from which the SmartClass will send and receive all SIP messages (for placing and
receiving calls).
– Verify that you specified the “Alias” on the General Settings menu as the SIP server or registrar
(the device that keeps track of all the registered devices), using the following format “phone-
Number@domain” where domain is either an IP address of the registrar or a literal domain
such as “jdsu.com”.
Issue
The VoIP delay measurement does not appear.
Resolution
The Delay result is only calculated if the RTCP signaling is active.
Issue
I have very little loss, but a high level of delay.
Resolution
Check your network. It may be experiencing high traffic.
Issue
I have a large amount of jitter, but no loss or delay.
Resolution
Check the setup of your router.
Video test problems
Individual program flows should be analyzed to ensure that both content quality and network perfor-
mance parameters are within desired network specifications. The suggested thresholds are listed
below:
Packet loss = less than or equal to 0.1%
Packet jitter = less than or equal to 5 msec*
PCR jitter = less than or equal to 5 msec*
Error indicator = zero count
IGMP latency = less than or equal to 200 msec
*Specific STB/decoder designs may be able to tolerate higher levels of jitter based on larger
buffer designs. Less than or equal to 10 msec may be acceptable.
Five to ten msec is a conservative PCR jitter level. As network designs and STBs increase
buffer sizes, the acceptable level will rise. The acceptable level for a particular network is a
company-specific issue.
When these measurements are made simultaneously on more than one channel, then content
problems can be easily separated from distribution network problems, a critical determination for
problem resolution.
Issue
I have continuity errors.
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