A service group is a set of channels for a given
service (for example, Video On Demand or OOB) delivered to or from a
particular set of subscribers. VTM organizes service groups into four
types:
- Broadcast: Inband video services for all customers in a particular set, usually based on region or ad-zone.
- Narrowcast: Inband video services (SDV and VOD) targeted to specific authorized customers.
- Downstream OOB (SCTE 55-1): Out-of-Band video services sent through multicast on a single RF port.
- Upstream OOB (SCTE 55-1): Out-of-Band return services sent to the Virtual Advanced Return Path Device (VARPD) through on a single RF port.
Each service group has one or more channels associated with it. A set of channels in a given service is delivered through some number of fiber nodes provided by one or more CCAP ports to the corresponding targets by a method determined by the service group type.
The four service group types can be placed in a matrix to clarify their differences:
by path:
Path Service Group Type Downstream Broadcast, Narrowcast, Downstream OOB Upstream Upstream OOB by service type:
Service Type Service Group Type Inband Broadcast, Narrowcast Out of Band Downstream OOB, Upstream OOB
VTM lets you organize all of the channels coming from the VUE and assign them to appropriate RxDs. After organizing the service groups, the assignment changes are pushed to the VUE and RxD so that the services reach their destinations.
Linear Source Management
VTM also supports Linear Sourced Management (LSM). In an LSM system, all broadcast services are delivered on QAM resources available within narrowcast service groups. An LSM deployment has the following operational advantages:- Performs service lineup channels without re-configuring EQAMs.
- Reduces the number of DAC controlled channel maps, as you do not need to create channel maps to handle different frequency usage across different locations.