February 14, 2008
October 25, 2013
Load Balancing (LB)
for the Cisco CMTS allows system operators to distribute cable modems across
radio frequency (RF) downstream (DS) and upstream (US) channels on the same
cable interface line card, or across multiple cable interface line cards in
some circumstances. Load balancing maximizes bandwidth and usage of the cable
Cisco IOS Release
12.2(33)SCA integrates support for this feature on the Cisco CMTS routers. This
feature is also supported in Cisco IOS Release 12.3BC, and this document
contains information that references many legacy documents related to Cisco IOS
12.3BC. In general, any references to Cisco IOS Release 12.3BC also apply to
Cisco IOS Release 12.2SC.
supports multiple methods to achieve greater bandwidth availability and
performance of the Cisco CMTS with subscriber benefits. These include static
and dynamic load balancing schemes, inter-line card and intra-line card
support, in some circumstances, configuration of load balancing groups (LBGs)
that entail multiple interfaces, multiple load balancing policies, and the
option to configure multiple additional load balancing parameters.
The load balancing
policies can be configured on the Cisco CMTS, indexed by an ID, to limit the
movement of CMs within a Load Balancing Group (LBG). The CM will forward
TLV43.1 in its registration request (REG-REQ) message, which is then parsed and
stored in the Cisco CMTS. A policy defines whether and when CMs can be moved
within their load balancing groups.
During dynamic load
balancing, the specified policy of the CM is checked to determine whether the
CM is allowed to move. However, existing static load balancing using a
frequency override technique and passive load balancing still take action at
Cisco IOS Release 12.3(17a)BC, and later 12.3 BC releases, load balancing is
enhanced and supported with Dynamic Channel Change (DCC). DCC in DOCSIS 1.1
dynamically changes cable modem upstream or downstream channels without forcing
a cable modem to go offline, and without reregistration after the change.
Cisco IOS Release 12.3(17b)BC4, and later releases, load balancing is enhanced
to distribute downstream load balancing with upstream channel loads in the same
upstream load balancing group. This improves upon the prior load balancing
limitation, in which load balancing was implemented on the basis of the entire
downstream channel load.
Cisco IOS Release 12.2(33)SCB, and later releases, load balancing is enhanced
to use rules and policies to decide on moving the CMs within their LB groups.
These policies are created on the Cisco CMTS and chosen on a per-CM basis using
type-length-value (TLV) portion (43.1, Policy ID) of REG-REQ. These policies
prohibit a modem from being moved or restricted.
A policy contains a
set of rules. When the policy is defined by multiple rules, all rules apply in
combinations. A rule can be defined as “enabled”, “disabled”, or “disabled
during time period.” Each rule can be used by more than one policy.
Cisco IOS Release 12.2(33)SCF1, DOCSIS 3.0 static modem count-based load
balancing is enhanced to use the dynamic bonding change (DBC) to modify the
following parameters of DOCSIS 3.0 cable modem with multiple transmit channel
(MTC) mode or multiple receive channel (MRC) mode without primary channel
(DSID) or DSID-associated attributes
association for encrypting downstream traffic
and additional load balancing schemes are supported on the Cisco CMTS, and
described in this document. This document describes all implementations of load
balancing on the Cisco CMTS, dependent upon the Cisco IOS release installed and
the desired parameters.
Cisco IOS Release 12.2(33)SCG1, the Cisco uBR-MC3GX60V line card and up to five
shared port adapters (SPAs) can be configured to the same LBG. You can:
Include all the
downstreams and upstreams of the SPA cards and the Cisco uBR-MC3GX60V line card
in the LBG.
MAC domain to include the SPA cards and the Cisco uBR-MC3GX60V line card.
fiber-node to include all the downstreams and upstreams of the SPA cards and
the Cisco uBR-MC3GX60V line card.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/. An account on http://www.cisco.com/ is not required.