CUCM Configuration
CUCM CUVA configuration includes the following steps:
Step 1 Configure regions with the maximum audio codec and video call speed to be used per video call.
Step 2 Configure the maximum allowed bandwidth used by video calls within or between locations.
Step 3 Configure the IP phone in CUCM to support CUVA.
Step 4 Verify CUVA support on the IP phone.
The CUCM region configuration specifies the audio codec type to use between regions, and the video setting specifies the bandwidth to use between regions. The audio codec and video call bandwidth fields perform similar functions. The audio codec value defines the maximum bit rate allowed for the audio channel in both audio only and video calls, and the video call bandwidth value defines the maximum bit rate for both the audio and video channel in a video call.
A video bandwidth value of none would pass audio-only calls, if the calling device has the Retry Video Call as Audio option enabled. The region settings are configured under System > Region. Each region must be configured to set the relationship to the other regions. The region configuration is illustrated in Figure 19-3.
Figure 19-3 Region Configuration
Figure 19-3 Region Configuration
The locations configuration in CUCM applies call admission control (CAC) to limit the number of audio and video calls that can be placed between locations. Locations typically represent geographical sites that are separated over an IP WAN.
Both the Audio Bandwidth and the Video Bandwidth fields offer the options of Unlimited and a numeric bandwidth value. Video bandwidth can be set to None to disallow video calls over the IP WAN (between locations). If numeric values are configured, they use two different calculation models:
■ Audio Bandwidth field: The value entered has to include the Layer 3 (IP) and Layer 4 (UDP/RTP) overhead required for the call. G.729 calls require 24 kbps because the audio codec operates at 8kbps, and the overhead operates at 16kbps. G.711 calls require 80 kbps because the audio codec operates at 64 kbps, and the overhead operates at 16kbps.
■ Video Bandwidth field: The value in the Video Bandwidth field is entered without overhead factoring. The video bandwidth is dynamically configured by subtracting the audio codec bandwidth from the full video bandwidth allowed.
Resource Reservation Protocol (RSVP) is the only topology-aware CAC mechanism. The H.323 gatekeeper and locations CAC mechanisms are not topology aware. H.323 gatekeepers and locations work on a hub-and-spoke physical topology premise. Most WANs today are partial-mesh or full-mesh environments using Multiprotocol Label Switching
(MPLS) virtual private networks (VPN). H.323 gatekeepers and locations can still be used in these environments with branch-to-branch connectivity, but the CAC mechanisms would not be able to make full use of the topologies' bandwidth capabilities. RSVP settings include the following:
■ Use System Default: The RSVP policy to the selected location matches the CUCM Default Interlocation RSVP Policy service parameter. The default value for this service parameter is No Reservation.
■ No Reservation: No RSVP reservations are made to the selected location.
■ Optional (Video Desired): A call can proceed as a best-effort audio-only call if no reservations for both the audio and video streams can be obtained. Cisco RSVP Agent continues to attempt RSVP reservation and informs CUCM if reservation succeeds.
■ Mandatory: CUCM does not ring the terminating device until RSVP reservation succeeds for the audio stream and, if the call is a video call, for the video stream as well.
■ Mandatory (Video Desired): A video call can proceed as an audio-only call if a reservation for the video stream cannot be obtained.
Most CUCM administrators use the RSVP system default.
NOTE More information about CAC using locations and RSVP-enabled locations is provided in the Cisco Unified Communications IP Telephony, Part 2.
To configure locations, navigate to System > Locations via CUCM Administration. Location configuration is illustrated in Figure 19-4.
Figure 19-4 Location Configuration
Figure 19-4 Location Configuration
You can find the IP phone configuration settings that are required for video support in the IP Phone Configuration window of CUCM Administration. The following configurations are necessary:
■ The PC that has CUVA installed needs to be physically connected to a PC port of the IP phone. Ensure that the PC port of the IP phone is not disabled under the CUCM IP phone configuration. The PC port is enabled by default.
■ The Video Capabilities field needs to be set to Enabled to allow the phone to participate in video calls. The video capabilities are disabled by default.
The Retry Video Call as Audio check box is located in the Phone Configuration window and is activated by default. If you uncheck this check box, a video call that fails to connect is not attempted as an audio-only call instead. Figure 19-5 shows the video-related settings of the IP phone.
Figure 19-5 Phone Video Settings
|
Forwarding Delay* |
| Disabled |
y |
|
PC Port * |
| Enabled |
M |
|
Settings Access* |
| Enabled |
d |
|
Gratuitous ARP* |
| Disabled |
d |
|
PC Voice VLAN Access* |
| Enabled |
d |
|
Video Capabilities* |
| Disabled |
d |
|
Auto Line Select* |
| Disabled |
el |
|
Web Access* |
| Enabled |
el |
|
Span to PC Port* |
| Disabled |
zi |
An IP phone or IP Communicator enabled for video displays a video camera icon in the lower-right corner of its LCD screen. Figure 19-6 shows this icon in IP Communicator.
Figure 19-6 IP Phone Video Verification
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