Cisco Headend System Release 2.7 Release Notes
SR 4.2 at a Glance
4012157 Rev B
5
Multiflow/Multicast Support (DOCSIS only)
In SR 4.0, Cisco introduced optional support for single-flow multicast IP routing.
With single-flow multicast IP routing, the network is configured to use one group
destination IP address to deliver out-of-band (OOB) data to multiple, DOCSIS-
capable DHCTs. To implement single-flow multicast, system administrators
configure the needed multicast streams (based upon the channel map and SI
requirements of the DBDS) and then create logical DOCSIS OOB bridges on the
DNCS. Network and cable modem termination systems (CMTS) are then configured
to join the appropriate multicast stream. The result is a bandwidth-conserving
technology that delivers a single stream of OOB data to multiple DHCT populations.
With single-flow multicast IP routing, the network is configured to use one group
destination IP address to deliver out-of-band (OOB) data to multiple, DOCSIS-
capable DHCTs. To implement single-flow multicast, system administrators
configure the needed multicast streams (based upon the channel map and SI
requirements of the DBDS) and then create logical DOCSIS OOB bridges on the
DNCS. Network and cable modem termination systems (CMTS) are then configured
to join the appropriate multicast stream. The result is a bandwidth-conserving
technology that delivers a single stream of OOB data to multiple DHCT populations.
With the release of SR 4.2, Cisco takes single-flow multicasting one step further by
offering support for multiflow/multicast. Multiflow/multicast represents Cisco’s
implementation in support of the Advanced DOCSIS Set-top Gateway (ADSG)
standard.
offering support for multiflow/multicast. Multiflow/multicast represents Cisco’s
implementation in support of the Advanced DOCSIS Set-top Gateway (ADSG)
standard.
Multiflow/multicast support enables you to harness the power of DOCSIS to
provide additional services and programming to your customers.
provide additional services and programming to your customers.
Note: While the DOCSIS option is a standard DNCS feature included with SR 4.2,
this option requires the appropriate network infrastructure to function within your
system. If you would like to purchase or activate this separate software product for
your system, contact your Cisco marketing representative.
this option requires the appropriate network infrastructure to function within your
system. If you would like to purchase or activate this separate software product for
your system, contact your Cisco marketing representative.
ADSG: Multiflow/Multicast
Under ADSG, set-tops “discover” for themselves where the OOB data flows are
located. The system accomplishes this by configuring the CMTS to publish a
directory of information, called the downstream channel descriptor (DCD). The
DCD describes, for the set-tops, the OOB data flows that are available on
downstream channels. Examples of OOB data flows include UNConfig, UNPassthru,
system information (SI), and BFS data. Each data flow is identified by a client ID.
located. The system accomplishes this by configuring the CMTS to publish a
directory of information, called the downstream channel descriptor (DCD). The
DCD describes, for the set-tops, the OOB data flows that are available on
downstream channels. Examples of OOB data flows include UNConfig, UNPassthru,
system information (SI), and BFS data. Each data flow is identified by a client ID.
The system supports the four following multiflow/multicast flows of data:
System-wide—OOB data that is intended for the entire set-top population
Hub-specific—OOB data intended for a given hub
Bridge-specific—OOB data intended for set-tops assigned to a given bridge
Site-specific—In a Regional Control System (RCS) environment, OOB data that is
intended for set-tops supported by a specific site
intended for set-tops supported by a specific site