Cisco Ip Communicator User Guide
As you can see, the 'sh arp' or 'sh ip arp' commands also give you the MAC addresses, so essentially the 'sh mac add' is only to get the port in which the device is connected. It helps to Ping the subnet's broadcast address (e.g. '10.1.1.255') to load the ARP table. Streaming Cisco IP Communicator into the Virtual Desktop To stream Cisco IP Communicator to the virtual desktop, you must first create an application profile using On-Demand Apps by XenApp. When creating the application profile for the Cisco IPC using the Citrix Stream Profile, you must select Advanced Install in the profile wizard.
Methods of Softphone Delivery
- How the softphone application is delivered to the virtual desktop
- How the audio is delivered to and from the user’s headset or microphone and speakers
- By installing in the virtual desktop image
Alternatively, best practice is, by streaming to the virtual desktop using On-Demand Apps by XenApp (a feature of XenDesktop Enterprise Platinum edition).
This second approach has manageability advantages because the virtual desktop image is kept uncluttered. Once streamed to the virtual desktop, the application executes in that environment just as if it had been installed in the traditional manner.
Streaming Cisco IP Communicator into the Virtual Desktop
When creating the application profile for the Cisco IPC using the Citrix Stream Profile, you must select Advanced Install in the profile wizard. This is necessary because some registry keys must update as part of the profiling.
The streaming profiling sequence consists of two steps. In the first step, the Cisco IPC installation is profiled by selecting the Run install program or command line script option in the profiling wizard. A virtual restart is not required. At the end of the Cisco IPC installation, do not select Launch Cisco IP Communicator.
Once the Cisco IPC installation in the profile has completed, select Perform additional installations in the profiling wizard.
Update some registry settings in the newly created profile. Select Edit registry in the profiling wizard.
Complete the following procedure to disable CDP to prevent the software from displaying error messages:
Caution! Refer to the Disclaimer at the end of this article before using Registry Editor.
Click on Launch Windows Registry Editor to bring up Regedit. Using Regedit, create the following DWORD value in the registry with value of 0:
HKLMSOFTWARECisco Systems, Inc.CommunicatorEnableCDP = 0
Note: This change in the registry also disables the E911 functionality of the IP Communicator without warning to the end user.
Select Finish Installations in the profiling wizard.
Complete, sign (optionally), and save the profile as you would with any other application.
Preparation of the Virtual Desktop
Deploying and Starting Cisco IP CommunicatorAt this point, you are ready to publish and start the Cisco IPC in the same way that you would any other streamed application. You should publish two applications provided by Cisco:
- The Audio Tuning Wizard, which allows the end-user to customize and tune their endpoint audio
- Ciscoconfiguration IP Communicator, which is the softphone itself
Delivery of Audio to the User Device
Isochronous USB Redirection
Citrix’s USB redirection technology provides a generic means of remoting USB devices, including isochronous USB devices, such as headsets and webcams. This approach is generally limited to LAN-connected users because the USB protocol tends to be sensitive to network latency and requires considerable network bandwidth. Isochronous USB redirection has been found to work very well with Cisco IP Communicator, providing excellent voice quality and low latency.
Citrix Audio Virtual Channel
The Citrix Audio Virtual Channel (CTXCAM) and the Bidirectional Audio feature of XenDesktop enable audio to be delivered very efficiently. XenDesktop takes the audio from the user’s headset/microphone, compresses it, and sends it over ICA to the softphone application on the virtual desktop using the Audio virtual channel. Likewise, the softphone’s audio output is compressed and sent in the other direction to the user’s headset or speakers. This compression is independent of the compression used by the softphone itself (that is G.729 or G.711). It is done using the Optimized-for-Speech codec. This is, in fact, the Speex codec (see http://www.speex.org/), and its characteristics are ideal for voice-over-IP (VoIP).
Cisco Ip Communicator V 8.6
Software on the User Device
To use either isochronous USB redirection or the optimized-for-speech audio codec, the user device must be equipped with either the Citrix on-line plug-in for Windows version 11.2 or later, or the Citrix Receiver for Linux version 11.100 or later. Citrix recommends you to use the latest versions of the Citrix Receiver to get the benefit of ongoing HDX enhancements.
System Configuration Recommendations
Check the priority of the Citrix Audio Service (CtxAudioService) on the Virtual Desktop Agent. If it is set to Normal, increase the priority to Above Normal. (It might in fact be a best practice to set the priority of CtxAudioService to High when using VoIP, but at the time of writing additional testing remains to be completed before confirming this as a recommendation.)
If using the Citrix Audio Virtual Channel, Citrix recommends setting the priority of the Audio virtual channel to 0 (real-time priority). See See CTX118836 - How to Optimize Audio for XenDesktop
Virtual Channel Priority changes have to be pushed out to the Virtual Desktop Agent by modifying the default PortICA XML configuration on the Delivery Controller. You can give “CTXCAM “(ClientAudioMapping virtual channel) higher priority through the XML Blob Priority section:
Edit XML file PortICASetDefaults.exe /o defaults.xml
In the <priority> section, the following setting should be specified:
< value>CTXCAM ,0</value>
All virtual channel names are seven characters long.
(0) - High Priority (Real-Time)
(1) - Medium Priority
(2) - Low Priority
(3) - Background Priority
Save the xml files.
PortICASetDefaults.exe /i modified_defaults.xml
To ensure adequate processing power for real-time traffic on a hypervisor, you must either allocate two virtual CPUs or disable the Citrix Gateway Protocol (CGP) which is used for the Session Reliability feature because it uses considerable CPU. Neither of these steps might be necessary on a powerful server.
If delivering softphones to users on a Wide Area Network (WAN) connection, the following additional configuration settings are recommended:
Obtain XenDesktop 4 Virtual Desktop Agent Update 2 (or above), included with XenDesktop 4 Feature Pack 1, which includes an enhancement for network congestion to prevent delay in the audio path. This enhancement introduces voice energy detection, allowing ambient noise (silent packets) to be discarded. This feature is controlled using a registry key.
Use Citrix Repeater and Branch Repeater between the data center and the remote office for Quality-of-Service (QoS). The Citrix Branch Repeater is able to distinguish the priorities of the various ICA virtual channels to ensure that high priority real-time Audio data gets preferential treatment.
Test Environment and Configuration
Windows Server 2008 Domain Controller
XenDesktop 4 Desktop Delivery Controller (DDC)
Windows XP Virtual Desktop Agent
Windows 7 Virtual Desktop Agent
Cisco IP Communicator 2.1.3
WANem WAN simulator Mov to wmv for mac osx.
The testing was performed using the Optimized-for-Speech audio codec and the bidirectional audio virtual channel.
A Windows 7 laptop with locally installed CIPC client software was used on the test network as the second party for calls made from Virtual Desktop Agent sessions as well as from a native CIPC client during testing.
A physical Windows XP workstation with locally installed CIPC client software was used as the XenDesktop client. Calls were made from this machine from locally installed CIPC and also from CIPC running in XenDesktop sessions which were started from this machine.
WANem running on a physical workstation was used for simulating WAN conditions in the network between the client machine and the XenDesktop Virtual Desktop Agents.
Virtual Desktop Agent Operating System Platforms
Windows XP SP 3 32-bit (Dual virtual CPU, 512 megabytes RAM, XenServer 5.5 virtual machine)
Windows 7 32-bit (Dual virtual CPU, 1024 megabytes RAM, XenServer 5.5 virtual machine)
Client Operating System Platform
Windows XP Service Pack 3 32-bit on the physical machine
Client configuration: Dell Precision T3400 (Intel Core2 Duo, 4 gigabytes RAM, 160 gigabyte hard drive)
WAN ConditionsA WAN simulator was used to introduce network disruptions on the network links. Testing was done with the following range of network conditions simulated by WANem running on a physical machine.
Bandwidth: 128 kilobits per second to 2 megabits per second
Latency: 0 milliseconds to 100 milliseconds one-way, 0 milliseconds to 200 milliseconds round trip
Packet loss: 0 percent to 2 percent
Jitter: 0 milliseconds to 20 milliseconds one-way (0 to 20 percent of latency)
Summary: Subjective Evaluation of Audio Quality over WAN
|Packet Loss (%)||Network Latency (roundtrip [ping time])|
|0 ms||50 ms||100 ms||150 ms||200 ms|
The generally recommended packet loss metric to support VoIP is 0.5 percent or less. However, depending on customer expectations, higher packet loss might be acceptable.
Impact of High Jitter
|Packet Loss (%)||Network Latency (roundtrip [ping time])|
|0 ms||50 ms||100 ms||150 ms||200 ms|
Cisco Ip Communicator For Mac Os
The XenDesktop 4 release does not include jitter buffering. High levels of VoIP jitter over the ICA connection from the user to the Virtual Desktop Agent platform can result in bad call quality or delay in the conversation.
On the LAN, isochronous USB redirection was used. The softphone performed “perfectly”. The voice quality was judged to be “essentially just as good as that provided by a physical Cisco handset.”
Testing with at-home workers was done using typical ADSL2 network connections ranging from 2 megabits per second to 20 megabits per second down, and 0.5 to 1.0 megabits per second up. The Optimized-for-Speech codec was used. The voice quality was judged to be “great” and “perfectly usable”.
Without voice energy detection (discarding of low-energy “silent” packets), latency on congested WAN connections can become excessive. Voice energy detection was introduced as a hotfix enhancement and is included in XenDesktop 4 Virtual Desktop Agent Update 2 (which is part of XenDesktop 4 Feature Pack 1).