Cisco Headend Digital Broadband Delivery System Manuel De Maintenance
Multiple Bootloader Carousels
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Important: When you set up multiple bootloader carousels, send each DHCT
image using only one bootloader source. Attempting to send the same DHCT
image to two different bootloader sources at the same time will cause the system
to display a Save Failed error message when saving the image to the second
bootloader source.
Determine Available Bandwidth for Multiple Bootloaders
This section provides inband data carousel recommendations and procedures for
determining how much bandwidth is currently available on the BFS QAM for
bootloader sources.
Why Determine Available Bandwidth?
Determining the amount of unused (or available) bandwidth for inband sources
Determining the amount of unused (or available) bandwidth for inband sources
ensures that your system has sufficient bandwidth for additional bootloader
carousels. Bootloader carousels require a data rate between 1.00 and 3.00 Mbps.
Example: If your BFS QAM has 4 Mbps of available bandwidth and you want to add
Example: If your BFS QAM has 4 Mbps of available bandwidth and you want to add
two bootloader carousels, each with a data rate of 3 Mbps, you cannot; there is only
enough available bandwidth to support one of the carousels.
Note: For assistance selecting a suitable rate for additional bootloader carousels,
Note: For assistance selecting a suitable rate for additional bootloader carousels,
refer to Recommendations for Data Carousel Rate Management Technical Bulletin (part
number 716377).
How Much Bandwidth Can My System Support?
Depending on your QAM modulation mode, the sum of your inband carousel rates
Depending on your QAM modulation mode, the sum of your inband carousel rates
plus any audio-visual content that is combined on the BFS QAM modulator should
not exceed the following totals:
Modulation Type
Direct ASI Bandwidth
BFS BIG Bandwidth
64-QAM modulation
26 Mbps
25 Mbps
256-QAM modulation
37 Mbps
36 Mbps
Determine Available Bandwidth for Your System
To determine the available bandwidth for your system, go to one of the following
To determine the available bandwidth for your system, go to one of the following
topics:
If your system uses ASI, go to Determining Available Bandwidth for Direct ASI
Systems (on page 56).
If your system uses a BFS BIG, go to Determining Available Bandwidth for BFS
BIG Systems (on page 57).