Provided by: iproute2_4.15.0-2ubuntu1.3_amd64 bug


       HFSC - Hierarchical Fair Service Curve's control under linux


       tc qdisc add ... hfsc [ default CLASSID ]

       tc class add ... hfsc [ [ rt SC ] [ ls SC ] | [ sc SC ] ] [ ul SC ]

       rt : realtime service curve
       ls : linkshare service curve
       sc : rt+ls service curve
       ul : upperlimit service curve

       • at least one of rt, ls or sc must be specified
       • ul can only be specified with ls or sc

       SC := [ [ m1 BPS ] d SEC ] m2 BPS
              m1 : slope of the first segment
              d  : x-coordinate of intersection
              m2 : slope of the second segment

       SC := [ [ umax BYTE ] dmax SEC ] rate BPS
              umax : maximum unit of work
              dmax : maximum delay
              rate : rate

       For description of BYTE, BPS and SEC - please see UNITS section of tc(8).


       HFSC  qdisc has only one optional parameter - default. CLASSID specifies the minor part of
       the default classid, where packets  not  classified  by  other  means  (e.g.  u32  filter,
       CLASSIFY  target  of iptables) will be enqueued. If default is not specified, unclassified
       packets will be dropped.


       HFSC class is used to create a class hierarchy for HFSC scheduler. For explanation of  the
       algorithm,  and  the  meaning  behind  rt,  ls, sc and ul service curves - please refer to

       As you can see in SYNOPSIS, service curve (SC) can be specified in  two  ways.  Either  as
       maximum delay for certain amount of work, or as a bandwidth assigned for certain amount of
       time. Obviously, m1 is simply umax/dmax.

       Both m2 and rate are mandatory. If you omit other  parameters,  you  will  specify  linear
       service curve.


       tc(8), tc-hfsc(7), tc-stab(8)

       Please direct bugreports and patches to: <>


       Manpage created by Michal Soltys (