Технические ссылки для Cisco Headend System Release 2.7
4014666 Rev B
3
Configuration Using a Single DCM
Configuration Using a Single DCM
This configuration uses a single DCM to receive the ASI output from the DNCS,
transport the BFS IB over a GbE transport network, and terminate the sessions on a
GQAM using its GbE interface.
transport the BFS IB over a GbE transport network, and terminate the sessions on a
GQAM using its GbE interface.
This configuration uses a dummy QAM for the automatically provisioned BFS
sessions and requires that continuous feed (CF) sessions be provisioned on the
GQAM.
sessions and requires that continuous feed (CF) sessions be provisioned on the
GQAM.
Note: It is beyond the scope of this document to provide detailed procedures for
setting up the network components and the DCM components of this configuration.
Please refer to the appropriate documentation for those procedures.
setting up the network components and the DCM components of this configuration.
Please refer to the appropriate documentation for those procedures.
Configuration Considerations
There are several options and recommendations to consider when you configure the
BFS for multicast transport.
BFS for multicast transport.
Multicast or unicast?
We recommend that you use multicast, since each remote headend distributes
the same BFS IB content to the set-tops.
We recommend that you use multicast, since each remote headend distributes
the same BFS IB content to the set-tops.
Multi-Program Transport Stream (MPTS) or Single-Program Transport Stream
(SPTS)?
You can configure the DCM to transmit the BFS IB sources in a single MPTS or
each source as a SPTS. Typically, we recommend SPTS because of the following
advantages:
(SPTS)?
You can configure the DCM to transmit the BFS IB sources in a single MPTS or
each source as a SPTS. Typically, we recommend SPTS because of the following
advantages:
Redundancy - If you have redundant BFS IB sources, then each source
should be an SPTS so the GQAM can choose an alternate DCM if an
individual BFS source fails. If you use MPTS, the GQAM must switch to the
alternate DCM for all BFS sources, even if only one BFS source fails.
should be an SPTS so the GQAM can choose an alternate DCM if an
individual BFS source fails. If you use MPTS, the GQAM must switch to the
alternate DCM for all BFS sources, even if only one BFS source fails.
Troubleshooting - Using SPTS makes BFS IB troubleshooting easier since
each BFS source has its own multicast IP address.
Example: A GbE MPEG analyzer can provide important information
regarding the BFS IB source (such as the data rate), using the multicast IP
address as a filter without requiring deeper MPEG2 packet inspection.
each BFS source has its own multicast IP address.
Example: A GbE MPEG analyzer can provide important information
regarding the BFS IB source (such as the data rate), using the multicast IP
address as a filter without requiring deeper MPEG2 packet inspection.
The disadvantage to using SPTS is that each BFS source must have a unique IP
address. Typically, the number of BFS IB sources is limited (usually less than 40),
so this might not be an issue for most operators.
If you use MPTS, the DCM uses the same IP address for all of the BFS sources.
address. Typically, the number of BFS IB sources is limited (usually less than 40),
so this might not be an issue for most operators.
If you use MPTS, the DCM uses the same IP address for all of the BFS sources.