Cisco Cisco TelePresence MX700 Guia Do Utilizador

D15029.01 Troubleshooting Guide TC6.0, April 2013. 

Copyright © 2013 Cisco Systems, Inc. All rights reserved. 

8

Network related issues

if you are experiencing bad video quality in calls with symptoms such as pixilation, smearing or pulsing 

of the image, the most likely cause for this is packet loss in the network.

Packet loss

You can check the packet loss information from the web interface, on the Touch panel if one is connected 

to your system, or on the 

System Information screen using a remote control.

Packet loss statistics – Touch panel
if you have a Touch panel connected, tap the 

 icon on the screen. Then tap 

and 

you will see the call status shown below. Here you can see the current packet loss statistics as well as 

the total packet loss statistic (average packet loss percentage over the whole call).

Packet loss statistics – remote control
press the Home button on the remote control to open the on-screen menu. Navigate to 

to open the 

System Information screen. You can find the packet loss 

information under the 

Video heading. 

Packet loss statistics - web interface

To check the packet loss on the current call log in to the web interface. On the top navigation panel 

click 

 

and then under 

Participants select the

symbol to expand the 

details visible. Now you can see the packet loss for the transmit and receive video and audio streams. 

As you can see below there is a constant 5% packet loss on both the transmit and receive streams 

which needs to be investigated. This is the loss percentage calculated over the entire call time frame.

On the web interface you can only see loss averaged for the duration of the call, meaning loss could 

have spiked higher during the call. 

Packet loss – more information 
Even a small amount of loss, for example 0.5%, can have noticeable effects on the image quality.

if you are calling another system running TC software directly (a point to point call), a technology called 

Clearpath will be used. This helps to mask the effects of packet loss and is enabled by default. When 

calling systems that do not support Clearpath, call quality will appear worse if there is packet loss, than 

a call to another TC based system with the same percentage loss. When Clearpath is not used the 

system will try and hide the loss when displaying the image (decoder concealment) and will down speed 

the bandwidth of the call. This results in the resolution being decreased thus lowering the amount of 

data being transmitted and thus hopefully reducing the packet loss. See “Appendix A - Other sources 

of information” on page 31 for information on the Clearpath whitepaper.

packet loss can be caused by many issues and after making some basic checks on the endpoint you 

should start to investigate your network to see where the loss is occurring and take steps to eliminate 

this loss.

Network Port speed
it is worth checking the duplex/speed settings of the network port on the system and network switch 

to ensure they are set to the same settings. We recommend that both the network interface on the 

system and the interface port of the network switch both be set to 

auto. For example if one is set at a 

fixed rate 100/full and the other to 

auto, the port speed and duplex negotiation can fail and produce 

mismatched settings. To check the status of the port on the codec go to 

 

and click on 

 and look under the 

 section. Ensure the system is using full duplex and 

that the speed matches that in the network switch.

To check the configuration of the network port look under 

 and 

then click on 

 and look under 

if both the network switch and the system are set to 

auto and the port speed and duplex settings do 

not match, set both to manual values (e.g. 100/full), restart and retest.

Troubleshooting Guide TC6.0