HT is a light version of HQoS Adjustment feature. The use of HQoS Adjustment functionality in place of HT is strongly encouraged.
When HT is enabled, the AN forks off (duplicates) the IGMP messages on the common mcast SAP to the subscriber SAP. IGMP states are not fully maintained per sub-host in the BNG, instead they are only tracked (less overhead) for bandwidth adjustment purposes.
Example of HT
Channel Definition:
configure
mcast-management
multicast-info-policy <policy-name>
<channel to b/w mapping definition>
Applying channel definition policy on a router/VPRN global level:
config>router>multicast-info-policy <policy-name>
config>service>vrpn>multicast-info-policy <policy-name>
Defining the rate object on which HT is applied:
configure
subscriber-management
host-tracking-policy <policy-name>
egress-rate-modify [agg-rate-limit | scheduler <sch-name>]
Applying the HT to the subscriber:
configure
subscriber-management
sub-profile <subscriber-profile-name>
host-tracking-policy <policy-name> => mutually exclusive with igmp-
policy