iftcntl(8) System Manager's Manual iftcntl(8)
NAME
iftcntl - View and modify network interface traffic control settings
SYNOPSIS
/usr/sbin/iftcntl interface command parameters
OPTIONS
This section is organized by the tasks you can perform with the iftcntl command. Each task subsection provides the iftcntl command syntax
and the options to use to complete the tasks.
Adding a Flow
Syntax: iftcntl interface addflow service parameters
Specifies the name of the interface on which to add a flow. Adds a flow on the interface specified by the interface parameter. Specifies
the service on which to add a flow. The valid value is cl (Controlled-Load) service. See RFC 2211 for more information. For the cl ser-
vice, the following parameters are mandatory: Specifies the average data rate in bytes per second. Specifies the peak data rate in bytes
per second. This parameter is typically ignored by Controlled-Load implementations, and is assumed to be the maximum line rate. Specifies
the bucket depth in bytes. This value should be several times greater than the size of the data packets, even for a constant data stream.
This ensures data packet conformance with the given traffic specification, even in cases of unavoidable slight jitter. Specifies the mini-
mum policed unit in bytes. Specifies the maximum packet size in bytes.
The following example adds a flow on tu0 for the cl service and shows the successful completion of the command. The example shows a
reservation suitable for a data source that sends a constant 500-byte packet data stream at 1 megabit per second (Mbit/s), or
125,000 bytes per second, using the User Datagram Protocol (UDP) and IPv4. The UDP and IPv4 headers create an overhead of 28 bytes,
which results in 528-byte packets and a data rate of 132,000 bytes per second. # iftcntl tu0 addflow cl 132000 0 4000 528 528 rhan-
dle 0xfffffc00053ff9a0
In the previous example, the second line, printed on stdout, contains the reservation handle (rhandle), and indicates that the com-
mand was accepted by admission control. To make this flow reservation effective, you must add a filter. This enables the packet
classifier to identify which packets belong to the flow. See the Adding a Filter section.
Deleting a Flow
Syntax: iftcntl interface delflow rhandle
Specifies the name of the interface on which to delete a flow. Deletes a flow reservation on the interface specified by the interface
parameter. This also deletes any filters associated with the reservation. Specifies the reservation handle of the flow.
Displaying a Flow
Syntax: iftcntl interface showflow -r rhandle
Specifies the name of the interface. Displays the flow reservation on the interface specified by the interface parameter and with the
reservation handle specified in the following option. Specifies the reservation handle of the flow.
The following example displays the flow reservation for interface tu0 and with the reservation handle 0xfffffc00053ff9a0: # iftcntl
tu0 showflow 0xfffffc00053ff9a0 rhandle policestyle orig service bitrate
------------------------------------------------------- 0xfffffc00053ff9a0 CL.EtherBasic MGMT 5 1100176
tspec r=132000 p=0 b=4000 m=528 M=528
policed 0/0, dropped 0/0, good 0/0, refcount=1, no filters
In the previous example, MGMT in the orig column indicates the iftcntl addflowmr as the originator of the flow. If RSVP originated
the flow, RSVP would appear in the orig column. The bitrate column indicates the (worst case) data rate (in bits per second) of the
flow including the link layer overhead (for example, the Ethernet header).
The second line for each flow displays service specific parameters of the flow. The third line displays statistics, expressed as
the number of packets/number of bytes, for the following packets: Packets not conforming to the given traffic specification.
Policed packets that had to be dropped. This is subset of the number of policed packets. Packets conforming to the traffic speci-
fication.
Displaying All Flows
Syntax: iftcntl interface listflows
Specifies the name of the interface. Displays all existing flow reservations on the interface specified by the interface parameter, unless
one of the following options is specified.
The following example displays all flow reservations for interface tu0: # iftcntl tu0 listflows rhandle policestyle
orig service bitrate ------------------------------------------------------- 0xfffffc0003f0e960 CL.EtherBasic RSVP 5
1141760 0xfffffc00053ff9a0 CL.EtherBasic MGMT 5 1100176
In the previous example, two reservations exist. The orig column indicates the originator of the flow, in this case RSVP and MGMT
(manually by using the iftcntl addflow command. The bitrate column indicates the (worst case) data rate (in bits per second) of the
flow including the link layer overhead (for example, the Ethernet header).
Adding a Filter
Syntax: iftcntl addfilter rhandle filter_spec
Adds a filter association to a flow specified by the rhandle parameter. The packet classifier in the IP output path of the kernel uses fil-
ter to decide whether a given packet is part of any flow for which a reservation exists. You can associate multiple filters with a single
flow. Specifies the name of the flow with which to associate the filter. Specifies one of the following filter specifications: Matches
packets with the given IP destination address (dest), destination port number (dest_port), and protocol number (proto). Valid proto values
include 17 (UDP) and 6 (TCP). Matches packet as in the previous filter specification, but also restricts the source IP address (src) and
port number (src_port) to the given values. Matches IPv6 packets with the given source address and flowlabel.
The following example adds a filter to flow 0xfffffc000220e140 and shows the successful completion of the command. # iftcntl tu0
addfilter 0xfffffc000220e140 16.32.128.43 4364 6 16.32.64.1 12865 fhandle 0x50000da01
In the previous example, the last line, printed on stdout, contains the filter handle (fhandle), and indicates that the command was
successful.
Deleting a Filter
Syntax: iftcntl delfilter rhandle fhandle
Deletes a filter with the filter handle specified by the rhandle and fhandleparameters. If you delete all filters associated with a flow,
the flow reservation remains; it is not deleted. Specifies the reservation handle of the filter. Specifies the filter handle of the fil-
ter.
Configure Parameters
Syntax: iftcntl interface config [param_name [value]]
Specifies the name of the interface. Displays the current, minimum, maximum, and default values for all traffic control parameters for the
interface specified by the interface parameter, unless one of the following parameters is specified. Displays the specified parameter,
unless a value parameter (value) is also specified. See the DESCRIPTION section for a list of parameters. Sets the parameter specified by
the param_name parameter to the value value.
The following example displays all traffic control parameters for interface tu0. See the Traffic Control Parameters section for a
description of each parameter.
# iftcntl tu0 config ipv4_wf_hashtsize = 229 (0..4294967295, default = 229) ipv4_wf_maxentries = 458 (0..4294967295, default =
458) ipv4_portfilt_hashtsize = 229 (0..4294967295, default = 229) ipv4_portfilt_maxentries = 458 (0..4294967295, default = 458) ipv6_flow-
filt_hashtsize = 229 (0..4294967295, default = 229) ipv6_flowfilt_maxentries = 458 (0..4294967295, default = 458) max_nonconform_queue_len
= 24 (0..2147483647, default = 24) max_total_r = 5000000 (0..18446744073709551615,
default = 5000000) max_total_b = 1000000 (0..18446744073709551615,
default = 1000000) max_nr_flows = 500 (0..4294967295, default = 500)
DESCRIPTION
The iftcntl command installs flows and filters on network interfaces that support traffic control. The Resource ReSerVation Protocol
(RSVP) typically performs this dynamically when it receives an application request. However, you can use iftcntl if you need to manually
establish a reservation. If invoked manually, no RSVP signaling occurs and only the specified interface is affected. The iftcntl command
operates independently from RSVP.
The iftcntl command fails on interfaces with no traffic control support.
You can use the iftcntl to configure traffic control parameters in order to constrain the amount of resources that RSVP is able to reserve.
If you want this to occur each time the system is booted, place the appropriate iftcntl command lines in the /etc/inet.local file.
If problems occur with RSVP reservations, use iftcntl showflow command to debug them. The rsvpstat -T command displays the reservation
handles for each reservation managed by RSVP. You then use the iftcntl showflow command and specify the reservation handle to display the
statistics for the flow.
Traffic Control Parameters
There are two types of traffic control parameters: those that configure the packet classifier and those that configure interfaces. The
following parameters configure the packet classifier: Specifies the number of hash buckets. Specifies the maximum number of filters.
Specifies the number of hash buckets. Specifies the maximum number of filters. Specifies the number of hash buckets. Specifies the maxi-
mum number of filters.
The following parameters configure an interface for Controlled-Load traffic control: Specifies the size of an interface output queue that
is to hold policed packets. Packets on this queue have a lower priority than best-effort packets. If you set this value to zero, all
policed packets are dropped immediately. Specifies the maximum total amount of bandwidth (in bits per second) available for reservations.
The default is half the link rate. Specifies the maximum total amount of token bucket space (in bytes) that can be allocated to reserva-
tions. Specifies the maximum number of flows for which reservations will be granted.
SEE ALSO
Commands: rsvpd(8), rsvpstat(8)
Files: inet.local(4)
Networking: RSVP(7)
Specifications: RFC 1633, Integrated Services in the Internet Architecture: an Overview
RFC 2211, Specification of the Controlled-Load Network Element Service
RFC 2216, Network Element Service Specification Template
iftcntl(8)