Chapter 31: Load Balancing
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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D2.0 and D3.0 CMs are load balanced across ATDMA and SCDMA channels.
D1.1 and D1.0 CMs are load balanced among remaining TDMA and T-A upstream channels.
If the modem steering flags are set to enable steering on D3.0 devices but set to disable D2.0 modem steering, then the
following applies:
D3.0 CMs are steered to ATDMA and SCDMA channels.
D3.0 CMs are load balanced across available ATDMA and SCDMA channels.
D2.0 CMs are load balanced across available TDMA, T-A, ATDMA and SCDMA channels.
D1.1 and D1.0 CMs are load balanced across available TDMA and T-A channels.
Note: Cross-checks verify that the CM to be moved has a CM config boot file version level greater than DOCSIS 1.0. D1.0
CMs contribute to the load on the channels and are therefore considered when determining whether or not a modem
needs to be moved, however, D1.0 CMs cannot be moved (via DCC or DBC).
Special Considerations When Steering D3.0 Devices to D2.0-Capable US Channels
Since DCC is used to steer Upstream Channel Bonded D3.0 bonded modems, only the primary US can be directed to a D2.0
capable channel. The non-primary US channels are not guaranteed to be on the D2.0-capable US channels when they are
chosen as part of Transmit Channel Set (TCS) assignment. Also note that to DCC a bonded modem, the reinit-mac
technique is required.
When tcs-load-balance is enabled, the primary US channel will be steered to an ATDMA channel by modem steering, but
the rest of the Transmit Channel Set will be comprised of the more lightly loaded channels within the modem’s load
balancing group. These may or may not be D2.0-capable channels.
When tcs-load-balance is disabled, the TCS calculated by the C4/c CMTS (if all US channels have acceptable US power
levels) is chosen from lowest to highest channel-id. In this case, it is recommended that any D2.0 capable US channels
(ATDMA) in the mac-domain be configured such that they are the lowest numbered channels in the cable-mac. This applies
to configurations in which the cable-mac(s) configured for the D3.0 modems contain a mix of non-D2.0 (TDMA & T-A) and
D2.0 (ATDMA) channels and the number of upstreams configured in the cable-mac is greater than the number of US
channels being bonded. This is done to help ensure that the non-primary US channels of the bonded modem will end up on
D2.0-capable modems.