NAME
pvctxctl
- display or control ATM PVC transmitter parameters
SYNOPSIS
pvctxctl
interface
[vpi[.blm Pp:vci]]
pvctxctl
interface
vpi[.blm Pp:vci]
[-n]
[-b max-bandwidth]
[-j vpi[.blm Pp:vci]]
[-p pcr]
DESCRIPTION
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
en(4).
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 interface. 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 VCs.
The options are as follows:
- interface
-
The
interface
parameter is a string of the form
``name unit'',
for example,
``en0''.
- vpi:[.blm Ppvci
- ]
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".
- -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[.blm Pp: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 PCRs.
For example, if two VCs (say 201 and 202) share a
45Mbps VP, use:
#
pvctxctl
en0
201
-b
45M
#
pvctxctl
en0
202
-b
45M
-j
201
- -n
-
This parameter is only for a sub interface.
Use NULL encapsulation instead of LLC/SNAP.
- -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.
SEE ALSO
en(4),
ifconfig(8),
pvcsif(8),
route(8)
BUGS
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 en0:
-
# ifconfig en0 10.0.0.1
# route add -iface 10.0.0.2 -link en0:3.0.0.c9
# pvctxctl en0 0xc9 -b 45M
For a shadow interface,
-
# pvcsif en0 # creates pvc0
# ifconfig pvc0 10.0.0.1 10.0.0.2
# pvctxctl pvc0 201 -b 45M