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PVCTXCTL(8)               BSD System Manager's Manual              PVCTXCTL(8)

     pvctxctl -- display or control ATM PVC transmitter parameters

     pvctxctl interface [[vpi]: vci]
     pvctxctl interface [vpi]: vci [-p pcr] [-b max-bandwidth] [-j [vpi]: vci]

     pvctxctl displays or controls the shaper parameters of an ATM VC.  When a
     shaper value is specified, pvctxctl sets a shaper to an ATM VC.  pvctxctl
     works for a PVC sub interface pvc(4) as well as a real ATM interface

     For a real ATM interface, the specified VC should be assigned beforehand
     by route(8).

     For a sub interface, pvctxctl assigns the specified VC to the sub inter-
     face.  If another VC is already assigned to the sub interface, the old VC
     is invalidated.

     Availability of shapers, the number of hardware shaper channels, and
     accuracy of shaping are all device dependent.  For example, ENI Midway
     chip has 8 shaper channels but the driver reserves one for non-shaping

     The options are as follows:

     Interface   The interface parameter is a string of the form ``name
                 unit'', for example, ``en0''.

     [vpi: vci]  The VC number to which the shaper is assigned.  When the VPI
                 number is omitted, VPI number 0 is assumed.  For example, to
                 assign a shaper to VPI=0 and VCI=201, the following forms can
                 be used: "201", "0xc9", "0:201", "0:0xc9".

     -p pcr      The PCR (Peak Cell Rate) parameter specifies the peak cell
                 rate in "cells per second".  If PCR value "0" is specified,
                 no shaper is assigned, which means cells are sent at full-
                 speed of the link.  If PCR value ``-1'' is specified, the
                 corresponding VC is invalidated.

     -b max-bandwidth
                 The PCR parameter can be specified also in ``bits per
                 second''.  The rate is the rate of AAL5 frame and the PCR is
                 calculated by the following form:

                       PCR = max-bandwidth / 8 / 48

                 ``K'' and ``M'' can be used as a short hand of ``000'' and
                 ``000000'' respectively.  For example, ``45M'' means
                 ``45Mbps'' or PCR value ``117187''.

     [-j [vpi:]vci]
                 The join parameter is intended for VP shaping.  The VC shaper
                 channel is shared with the existing VC, which means the sum
                 of the cell rates never exceeds the maximum PCR among the
                 shared VCs.  On the other hand, when the shaper channel is
                 not shared, the sum of the cell rates could be the sum of the

                 For example, if two VCs (say 201 and 202) share a 45Mbps VP,

                       # pvctxctl en0 201 -b 45M
                       # pvctxctl en0 202 -b 45M -j 201

     -n          This parameter is only for a sub interface.  Use NULL encap-
                 sulation instead of LLC/SNAP.

     en(4), ifconfig(8), pvcsif(8), route(8)

     A real ATM interface and a sub interface require different sequences to
     set a shaper.  For example, to assign a 45Mbps shaper to VC 201 (0xc9) of

           # ifconfig en0
           # route add -iface -link en0:3.0.0.c9
           # pvctxctl en0 0xc9 -b 45M

     For a shadow interface,

           # pvcsif en0                            # creates pvc0
           # ifconfig pvc0
           # pvctxctl pvc0 201 -b 45M

BSD                            December 29, 1997                           BSD