Configuring the DMP Global Settings
This section includes the following topics:
■ Time Protocols and Synchronization on the Digital Media Players
■ How to Configure NTP and PTP on the Digital Media Players
Network Time Sources for the Digital Media Players
The DMP supports two different network time sources under the global DMP settings:
■Network Time Protocol (NTP)—This is the default.
■Precision Time Protocol (PTP)—Required for video wall synchronization feature and for DMP-to-DMP synchronization.
NTP and PTP settings are provisioned globally for all digital media players. The Cisco Vision Dynamic Signage Director server is provisioned as the default NTP source for all media players.
Note: When PTP is configured, only the DMP PTP leader derives its clock using NTP.
For the most accurate synchronization for video playback across DMP devices, the time on the target media players must be almost the same. NTP does not provide this level of time synchronization and accuracy, so PTP is also required.
PTP Leader and Members
The DMP is capable to serve as a PTP leader or as a PTP member, where members obtain their time from the leader. The PTP leader, in turn, will get its time from an NTP server.
By default, all DMP devices are designated as eligible leader candidates.
DMP-to-DMP Content Synchronization
The DMP-to-DMP Content Synchronization feature for the digital media player synchronizes content rendering of playlist items on the displays.
This synchronization includes transitioning from one item to the next (such as for still images), and more accurate playback and rendering of local video content. For local video, this serves as the foundation for implementing video ribbon boards and video walls. This requires cabling of a single media player per display.
Note: Widgets, external URLs, and multicast video tuning synchronization are outside the scope of this feature.
Zone-Based Video Wall Synchronization
Zone-based video wall synchronization is an alternative form of synchronization available for DMP devices participating in a video wall. It makes use of a mechanism native to the DMPs that helps a group of media players stay in content sync with a leader device over multicast.
The primary benefit of this form of synchronization is that if any DMP device that is not the leader in the video wall reboots, it will “catch up” to play whatever content item that the rest of the video wall is currently playing.
If a DMP device reboots in a video wall that is not using zone-based video wall synchronization (using normal DMP-to-DMP synchronization), the trade-off is that the rebooting device synchronizes with the rest of the video wall at the next content item in the playlist, or at replay of a single-item playlist.
The general guideline is to use zone-based video wall synchronization for dedicated video walls that are playing video content longer than 15 minutes. While you can use this form of synchronization for all video walls, the synchronization benefit is best seen with longer-playing video wall content.
Use Cases for Video DMP-to-DMP Synchronization with PTP
PTP is particularly beneficial for the following use cases in the Cisco Vision Dynamic Signage Director network:
■Using video background for Dynamic Menu Boards (DMBs) that show primary and secondary regions of the event.
■Sponsored moment of exclusivity.
■When a team scores a goal, a secondary video using the luma key feature can be shown on screen overlaying a full screen video showing the live event.
■Video-based ads.
■Ads in region 2 or 3 (or L-wraps) can now be video content. For L-wraps, use the luma key so that the live multicast video displays.
Restrictions for PTP on the Digital Media Players
Before you configure PTP on the digital media players, consider the following restrictions:
■By default, PTP messages will not cross VLANs and PTP leader candidates need to be identified for each VLAN and configured in the Configuration > System Configuration page.
■The system supports a configurable Precision Time Protocol (PTP) Time To Live (TTL) setting in the Configuration > System Configuration page. The PTP TTL specifies the number of VLANs that can be crossed for selection of a PTP leader. The default value of 1 (recommended) means that each VLAN will elect its own PTP leader.
Note: For ease of configuration for venues with multiple VLANs, the system is configured by default to list all digital media players as eligible PTP leader candidates. However, be aware that although this simplifies configuration, the time that it takes for the devices to arbitrate a leader device in each network will vary, and depends on the number of eligible devices in each network.
■Content synchronization for video playback on the digital media players relies on precise time across DMPs using PTP. If the DMPs are playing video and one of the devices reboots, the rebooting unit will restart video playback from the beginning and will only synchronize with the other players when the next item in the playlist is rendered.
■If digital media players are participating in zone-based content synchronization for video walls, with some enhanced synchronization capability, the rebooting unit will synchronize with the current item being played by the device leader in the video wall. For more information, see “Working with Video Walls” in Release 6.3: Cisco Vision Dynamic Signage Director Operations Guide.
Guidelines for NTP and PTP on the Digital Media Players
Before you configure NTP and PTP on the digital media players, consider the following guidelines:
■For new installations of Cisco Vision Dynamic Signage Director, PTP is the default time source for the digital media players, with NTP as the default time source for the elected PTP leader.
NTP Guidelines
■Each digital media player designated as PTP leader (per VLAN) will use NTP as its time source. The other devices in the network operate using a PTP reference clock from the elected PTP leader.
■When PTP is disabled (not recommended), all devices use NTP to set their local clock.
Note: For synchronized video playback, NTP alone cannot be relied upon for devices and PTP must be used.
■The default NTP synchronization interval with the host time server is one hour and is configurable.
■An NTP source must be configured in Cisco Vision Dynamic Signage Director. By default, the Cisco Vision Dynamic Signage Director server is configured as the device NTP host.
PTP Guidelines
■PTP version 2 is supported only for the digital media players and applies globally to all devices in the Cisco Vision Dynamic Signage Director network when configured.
■PTP configuration includes a PTP domain and a set of leader candidates:
–PTP domain—Default is 0.
Be sure that this domain does not conflict with any other PTP domain (and multicast addressing) in use in your network, and revise as needed. See table “Global DMP Settings—PTP Property Values” for more information.
–PTP leader candidates—Default is *.
This specifies that all devices in the network are eligible as leader candidates and will go through arbitration to designate a leader for their respective subnets.
■If you revise the default PTP leader candidates configuration, you must configure one or more devices as leader candidates in a semicolon-separated list of IP addresses for each VLAN.
A minimum of two leader candidates per network is recommended.
■If there is an in-house PTP leader for your network, leave the “PTP leader candidates” property value blank. However, this configuration is only supported for venues without multiple subnets.
Modifying the PTP and NTP Configuration on the Digital Media Players
By default the NTP and PTP services are automatically enabled and configured for digital media players. Use this task if you need to modify the default settings described in Table 2 and Table 3.
Table 2 Global DMP Settings—PTP Property Values
Property (Registry key) |
Description |
Values |
(Globaldmpsetting.common.init.ptp.domain)
|
Domain number for the PTP network, which defines the multicast address for PTP communication.
|
For IEEE-1588 PTP, possible values are:
|
(Globaldmpsetting.common.init.ptp.master.host)
|
Eligible devices for leader candidate selection.
|
■ * —(Default). Wildcard pattern that specifies all devices in the network as eligible PTP leader candidates. ■Semicolon-separated IPv4 addresses of the devices for each subnet. Example:
10.0.0.3;10.0.0.4;192.168.0.5;192.168.0.6
■blank—Specifies that a PTP leader source external to Cisco Vision Dynamic Signage Director is used. This configuration is only valid for a venue without devices in multiple subnets. |
(Globaldmpsetting.common.init.ptp.ttl)
|
Number of VLANs that can be crossed for selection of a PTP leader.
|
Note: Best practice is to retain the default value of 1 for election of a PTP leader per video wall. With a TTL > 1, degradation in local video synchronization can occur.
|
Note : If the domain setting gets blanked, it will disable PTP on all DMPs. The DMPs will revert to using NTP as the time source.
Table 3 Global DMP Settings—NTP Property Values
Property (Registry Key) |
Description |
Values |
(Globaldmpsetting.common.deploy.ntpc.hostname)
|
IPv4 address of the NTP server.
|
Default—IP address of the Cisco Vision Dynamic Signage Director server.
|
(Globaldmpsetting.common.deploy.ntpc.interval)
|
Number of seconds that the device waits before trying to synchronize its time with the configured NTP host.
|
|
(Globaldmpsetting.common.deploy.ntpc.timezone)
|
Code for the timezone to be used.
|
|
To modify the standard NTP and PTP configuration on all DMPs:
1. Log into the Cisco Vision Dynamic Signage Director server as an administrator.
2. Click Configuration > System Configuration > Global DMP Settings > Time Source (Figure 1).
Figure 1 Global DMP Settings for NTP and PTP on the DMPs
3. (Optional) Change the global PTP properties as required for your network. Click the Edit icon (pencil). Refer to Table 2.
4. (Optional) Change the global NTP properties as required for your environment. Click the Edit icon (pencil). Refer to Table 3.
5. Click Save.
6. Reboot the devices.
Verifying PTP Operation for the Digital Media Player
This section describes how to verify the PTP configuration and also the operation of PTP for your devices.
To verify the PTP operation for the digital media player:
1. Open your browser and navigate to one of the DMPs:
http:// sv4k-ip-address /ptp.html
2. Identify the PTP leader by finding the unit that has an “offsetFromMaster” value of 0.0.
Figure 2 highlights the PTP leader and shows a network where PTP is operating successfully with 12 members.
Figure 2 Successful PTP Clock Operation