Cisco Explorer Series Staging Manual page 46

Chapter 3 Optimize Your System Performance for Downloads and Staging
4 SGM IB carousels are added to the default carousels when Switched Digital Video (SDV)
is enabled on the system. These carousels provide the mini-carousel discovery files to the
SDV client to determine the mini-carousel frequencies available. This method of mini-
carousel discovery is used only by SARA SDV clients.
In addition, SARA SDV client software supports an alternate means of obtaining its mini-
carousel, which does not require downloading the mini-carousel discovery file. If the SDV
client does not require the mini-carousel discovery file, then all SGM IB carousels should
be disabled/stopped. If the SARA SDV client uses the mini-carousel discovery file
method, then you will enable these carousels based on the number of SDV-enabled
service groups are defined on the system.
Each SGM IB carousel supports a maximum of 476 SDV-enabled service groups. Refer to
the DNCS release notes for your system release for more details on enabling these
carousels.
5 The BFS IB total includes CAM IB, but does not include any SGM IB carousels.
6 The servicegroupmap.dat file is distributed using the OOB carousel. With systems
expanding the number of service groups and/or number of QAMs per service group, the
default recommendation may need to be increased for better service group discovery. The
following table provides some guidelines on when to increase this rate.
Number of Service
Groups
< 400
< 800
400 – 800
800 – 1600
800 – 1200
1600 – 2400
Note: 150 Kbps is the maximum recommended rate for the OOB carousel to ensure
sufficient QPSK downstream bandwidth for other OOB messaging.
For systems that surpass the above number of service groups and QAM combinations,
DNCS SR 4.2.1.30 (and later) allows you to select the number of QAMs that are included
in the servicegroupmap file. The following table provides our rate recommendations,
assuming that each service group is limited to 3 QAM carriers in the servicegroupmap
file.
Number of Service
Groups
< 2000
2000 – 4000
4000 – 6000
36
Number of QAMs per
Service Group
16
8
16
8
16
8
Number of QAMs per
Service Group
3
3
3
Recommended Rate
50 Kbps
50 Kbps
100 Kbps
100 Kbps
150 Kbps
150 Kbps
Recommended Rate
50 Kbps
100 Kbps
150 Kbps
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