DHCP load test tool

Table of Contents

Introduction

This document is a reference manual for Nippon C.A.D. Co., Ltd.'s "dhcpperf" DHCP load testing tool.

The DHCP load testing tool simulates the sending of DHCP address requests by multiple clients simultaneously to a DHCP server in order to test and evaluate its performance under high loads. Scenario data files are used for the DHCP information, making it possible for clients to specify not only lease requests and releases, but also relay routes and other unique options when performing testing.

Quick Start Guide

This tool is started using the command format below.

To perform a basic test, run the following command.

./dhcpperf -v -s <DHCP server IP address> <device name>

Replace <device name> with the name of the network device in the network where the DHCP server is located. Unicast will be used to send DHCPDISCOVER messages, DHCPREQUEST messages, and DHCPRELEASE messages to the specified DHCP server IP address.

When it is not possible to communicate with the DHCP server, measurement will not be successful, and the following will be displayed.

secs success failure  active | minimum current maximum | average slowest fastest
   1       0       0       0 |       0       0       0 |       0       0       0
   2       0       0       2 |       0       0       0 |       0       0       0
   3       0       0       3 |       0       0       0 |       0       0       0
Unable to continue.

When it is possible to communicate with the DHCP server, a message which begins as follows will be displayed.

secs success failure  active | minimum current maximum | average slowest fastest
   1       0       0       0 |       0       0       0 |       0       0       0
   2       1       0       1 |       0       0       0 |     303     303     303
   3       2       0       1 |       0       2       2 |     303     303     303
...

First, the DHCP server's performance limit will be measured.

secs success failure  active | minimum current maximum | average slowest fastest
  19    4125     133    2726 |       0    2000    2000 |     302     332     300
Inital probe complete: High-water mark is 2000 clients/second.

The "current" value indicates the number of DHCPDISCOVER messages sent per second. When 2,000 messages per second are sent, one message will be sent every 0.5 milliseconds. See the "Outputting statistical information" section for detailed explanations of each column.

When the maximum number of transactions has been determined, measurement will begin at roughly half the maximum number of transactions.

The default measurement time is 120 seconds. If the number of errors is low, the measurement will be considered to have been successful, the number of transactions will be increased, and measurement will begin again. Conversely, if the number of errors is high, the number of transactions will be decreased, and measurement will begin again.

secs success failure  active | minimum current maximum | average slowest fastest
  20    4936     505    3579 |       0       0    2000 |     302     332     300
  21    5174    1008    2334 |       0       0    2000 |     302     334     300
  22    5174    1000    1334 |       0       0    2000 |     302     334     300
  23    5174    1334       0 |       0       0    2000 |     302     334     300
Preparing for next test run.
  24    5174       0       0 |       0       0    2000 |     302     334     300
  25    5174       0       0 |       0       0    2000 |     302     334     300
  26    5174       0       0 |       0       0    2000 |     302     334     300
  27    5174       0       0 |       0       0    2000 |     302     334     300
  28    5174       0       0 |       0       0    2000 |     302     334     300
Beginning test run: 1000 clients/second for 120 seconds.
  29       0       0       0 |       0    1000    2000 |       0       0       0
  30     566       0     372 |       0    1000    2000 |     301     303     300
  31    1372       0     507 |       0    1000    2000 |     301     304     300
  32    2160       0     659 |       0    1000    2000 |     301     304     300
  33    2943     134     681 |       0    1000    2000 |     301     304     300
Stopping run after 33 seconds; 134/7056 clients failed.
Preparing for next test run.
  33    2943       0     682 |       0       0    1000 |     301     304     300
  34    3182     134     309 |       0       0    1000 |     302     335     300
  35    3182     155     154 |       0       0    1000 |     302     335     300
  36    3182     154       0 |       0       0    1000 |     302     335     300
  37    3182       0       0 |       0       0    1000 |     302     335     300
Beginning test run: 500 clients/second for 120 seconds.
  38       0       0       0 |       0     500    1000 |       0       0       0
...
 706   88228       0     455 |     775     777     779 |     302     377     300
Succeeded test run: 88228/88246 clients/seconds.

Ultimately, the measurement results with the fewest errors and largest number of successful transactions will be reported as the DHCP server's transaction processing capability.

Finished and report: 777 transactions per second.

This indicates that 777 transactions can be processed per second.

This completes the basic testing process. The process described is for a basic test. Scenario data files can be used to perform tests with detailed parameter settings.

Installation

This tool is available for 64-bit CentOS 5 and CentOS 6. The RPM version can be installed using the following command.

rpm -ivh dhcpperf-<version numbers>.rpm

This will unpack the following files.

/usr/bin/dhcpperf
/usr/share/ncad/dhcpperf/expand.dat
/usr/share/ncad/dhcpperf/discover.dat
/usr/share/ncad/dhcpperf/release.dat
/usr/share/ncad/dhcpperf/request.dat

Startup options

  • -h –help
    Displays the help message
  • –usage
    Displays a simple help message
  • -v –progress
    Displays statistical information, updated every second
  • -s –server server IP address [, server IP address …]
    Specifies the DHCP server's IP address. Testing is performed using a broadcast address if no DHCP server IP address is specified.
  • –test-duration time
    Specifies the measurement time (in seconds). The default value is 120 seconds.
  • –hardware XX:XX:XX:XX:XX:XX
    Specifies the MAC addresses to use for requests.
  • –hardware-length number
    Specified the length of MAC address to for use requests. number increase incrementally from this value. When the last three bytes reach their maximum value, the last three bytes only are returned to 0.
  • –clients number
    Specifies the initial number of simultaneous requests per second.
  • –limit number
    Specifies the number of upper limit of clients.
  • –timeout time
    Specifies the amount of time considered to be a DHCP packet timeout. The default value is 3 seconds.
  • –cooldown-time time
    Specifies the cooldown time between completing one measurement and beginning the next measurement. The default value is 5 seconds.
  • –error-threshold threshold value
    Specifies the failure ratio which is treated as an error (=number of failures รท number of successes x 100). The default value is 0.1%.
    (when set to 0.1, one error for every 1,000 successes is not considered an error)
  • –recv-port port number
    Specifies the number of the port on which to receive DHCP packets. When not specified, the default value for client measurement is port number 68, and the default value for relay measurement is port number 67.
  • –send-port port number
    Specifies the number of the port to which to send DHCP packets. The default value is port number 67.
  • –nthreads number of thread pools
    Specifies the number of thread pools the program can use. This number can be matched to the number of cores to improve processing efficiency.
  • –disable-promiscuous
    Don't use promiscuous mode to communicate.
  • –test-mode [mode]
    highload: Measures at the highest speed, gradually stepping down.
    slowly: Gradually steps up the load.
    endless: Applies a constant load without stopping.
    once: Performs processing one time.
  • –log-file file name
    Specifies the name of the saved debug log file.
    (* Please note that log rotation is not performed, so log files can become extremely large.)

Scenario data files

The scenario data file can be used to define the contents of the DHCP requests.

  Name Data type Remark
  Hops Integer  
  Secs Integer  
  Broadcast 0 or 1  
  Ciaddr IP address  
  Yiaddr IP address  
  Siaddr IP address  
  Giaddr IP address  
  Chaddr IP address  
  Sname String  
  File String  
  1…255 Variant  
  53 DHCP message name DHCP Message Type
  54 IP address Server Identifier
       

DHCP message name

The following string can be used for the DHCP message name.
*Not case sensitive

  • DHCPDISCOVER
    Sends DHCPDISCOVER messages. Normally, for clients, Broadcast = 1 is specified, and for relays, Giaddr = <DHCP server address> is specified.
  • DHCPREQUEST
    Sends DHCPREQUEST messages.
  • DHCPRELEASE
    Sends DHCPRELEASE messages.
  • DHCPDECLINE
    Sends DHCPDECLINE messages.
  • DHCPINFORM
    Sends DHCPINFORM messages.

Variant

The variant can be entered in the form of a string, IP address list, decimal value, or hexadecimal value.

  • Strings is indicated by putting them in double-quotes.
    Ex.: "dhcpperf"
  • IP address lists is indicated by entring them in IPaddress form, such as 192.168.100.1, separated with commas.
    Ex.: 192.168.0.100, 192.168.0.101, 192.168.0.102
  • Decimal values are indicated by entering values between 0 and 255, separated by commas.
    Ex.: 1,2,3,4,5,6,7,8,9
  • Hexadecimal values are indicated by entering two-digit values between 00 and FF, separated by colons.
    Ex.: 00:01:02:03

Special symbol @auto

When @auto is specified for a parameter value, the same parameter in the response data from the DHCP server is used.

For example, When @auto is specified for option 54, when the response message contains option 54, it is transmitted as-is as a request message. When no option parameter number is included in a DHCPDISCOVER message or response message, no option parameters are included in the next request message. As a general rule, the same response parameters are used, but special values can be set for some parameters by specifying @auto.

Broadcast

When @auto is specified for the Broadcast parameter, the Broadcast parameter will be set to 0 if the command line -server option is specified. If the command line -server option is not specified, the Broadcast parameter will be set to 1.

Therefore, by specifying Broadcast=@auto for DHCPDISCOVER messages only, and specifying Broadcast=0 for all other messages, such as DHCPREQUEST messages, the tester can be switched between client operation or relay operation based on whether the -server command line argument has been specified.

Ciaddr

When @auto is specified for the Ciaddr parameter, the IP address of the Yiaddr parameter in the response from the DHCP server will be set.

Giaddr

When @auto is specified for the Giaddr parameter, the IP address assigned to the device name will be set if the command line -server option is specified.

Chaddr

When @auto is specified for the Chaddr parameter, the MAC address used in the inquiry sent to the DHCP server will be randomized. The randomized MAC addresses will be assigned by using the MAC address value specified with the -hardware command line argument, but with different values for the last three bytes of the address.

*Due to program design, these MAC addresses will generally be sequential, but note that the MAC addresses are not guaranteed to be sequential.

Option 50

When @auto is specified for the Option 50 parameter, the IP address of the Yiaddr parameter in the response from the DHCP server will be set. This parameter is not normally set for DHCPDISCOVER messages. When this parameter is set, Option 50 will be added to DHCPDISCOVER messages.

Option 54

When @auto is specified for the Option 54 parameter, the DHCP server IP address will be specified for Option 54 of DHCPDISCOVER messages specified with the -server command line argument. Therefore, by specifying 54=@auto for all messages, the tester can be switched between client operation or relay operation based on whether the -server command line argument has been specified.

Option 61

When @auto is specified for the Option 61 parameter, the client ID will be automatically allocated. The automatically allocated ID is a 7 byte long ID. The first byte is 0x01, and the remaining bits are the MAC address.

Manipulating the scenario data file by using the -server command line argument

By specifying @auto for Broadcast, Giaddr, and Option 54 in the scenario data file, the tester can be automatically switched between client operation or relay operation based on whether the -server command line argument has been specified. Specific values can also be set for Broadcast, Giaddr, and Option 54 in the scenario data file. When specific values are set, the -server command line argument will be ignored, and testing will be performed based on the scenario data.

Performing DHCP client testing using scenario data

Scenario data defines one item of data transmitted by the tool. Multiple scenario data files can be specified from the command line to control communications with the DHCP server. Each transaction is composed of a series of operations, and the tool measures how many transactions the DHCP server can respond to correctly per second.

The easiest way to measure DHCP server performance is to use the "5 way hand-shake": DHCPDISCOVER -> DHCPOFFER -> DHCPREQUEST -> DHCPACK -> DHCPRELEASE.

This tool uses scenario data files for DHCPDISCOVER, DHCPREQUEST, and DHCPRELEASE messages. Below is an example of the structure of a file that defines scenario data for a "5 way hand-shake" test.

  • discover.dat
Hops=0
Secs=0
Broadcast=@auto
Ciaddr=0.0.0.0
Yiaddr=0.0.0.0
Siaddr=0.0.0.0
Giaddr=0.0.0.0
Chaddr=@auto
Sname=""
File=""
12="dhcpperf"
53=DHCPDISCOVER
55=1,3,6,15
61=@auto
  • request.dat
Hops=0
Secs=0
Broadcast=@auto
Ciaddr=0.0.0.0
Yiaddr=0.0.0.0
Siaddr=0.0.0.0
Giaddr=@auto
Chaddr=@auto
Sname=""
File=""
12="dhcpperf"
53=DHCPREQUEST
54=@auto
55=1,3,6,15
50=@auto
61=@auto
  • release.dat
Hops=0
Secs=0
Broadcast=@auto
Ciaddr=@auto
Yiaddr=0.0.0.0
Siaddr=0.0.0.0
Giaddr=@auto
Chaddr=@auto
Sname=""
File=""
12="dhcpperf"
53=DHCPRELEASE
54=@auto
55=1,3,6,15
50=@auto
61=@auto
./dhcpperf -v <Device name> ./discover.dat ./request.dat ./release.dat

*Client testing uses a broadcast address, so the -server IP address command line argument cannot be specified. Also note that broadcast flag 1 is specified for the discover.dat Broadcast parameter.

Relay agent testing using scenario data

When performing testing via a relay agent, the IP address of the tool must be specified for Giaddr, and the DHCP server IP address must be specified for Option 54. If @auto is specified for Broadcast, Giaddr, and Option 54, the IP address specified in the -server command line argument or the IP address set as the <device name> will be automatically used.

Below is an example of the structure of a file that defines scenario data for a "5 way hand-shake" relay test.

  • discover.dat
Hops=0
Secs=0
Broadcast=@auto
Ciaddr=0.0.0.0
Yiaddr=0.0.0.0
Siaddr=0.0.0.0
Giaddr=@auto
Chaddr=@auto
Sname=""
File=""
12="dhcpperf"
53=DHCPDISCOVER
54=@auto
55=1,3,6,15,119,95,252,44,46,47,5,197,43,69,42,201,202
61=@auto
82=01:04:20:00:00:1e:02:06:70:58:12:35:13:33
  • request.dat
Hops=0
Secs=0
Broadcast=@auto
Ciaddr=0.0.0.0
Yiaddr=0.0.0.0
Siaddr=0.0.0.0
Giaddr=@auto
Chaddr=@auto
Sname=""
File=""
12="dhcpperf"
50=@auto
53=DHCPREQUEST
54=@auto
55=1,3,6,15,119,95,252,44,46,47,5,197,43,69,42,201,202
61=@auto
82=01:04:20:00:00:1e:02:06:70:58:12:35:13:33
  • release.dat
Hops=0
Secs=0
Broadcast=@auto
Ciaddr=@auto
Yiaddr=0.0.0.0
Siaddr=0.0.0.0
Giaddr=@auto
Chaddr=@auto
Sname=""
File=""
12="dhcpperf"
50=@auto
53=DHCPRELEASE
54=@auto
55=1,3,6,15,119,95,252,44,46,47,5,197,43,69,42,201,202
61=@auto
82=01:04:20:00:00:1e:02:06:70:58:12:35:13:33
./dhcpperf -v -s <DHCP server IP address> <device name> ./discover.dat ./request.dat ./release.dat

If different Broadcast parameters are set for client and relay testing, and @auto is specified for the Giaddr parameter, the tester can be switched between client operation or relay operation based on whether the -server command line argument has been specified.

*General purpose scenario data is stored in usr/share/ncad/dhcpperf. Testing can be easily performed by editing scenario data files and adding options.

Kinds of load testing

  • highload
    Measures the maximum load first. The load is increased every second. When the error rate exceeds the threshold, the maximum load is considered to have been reached. Once the maximum load has been determined, a constant load is applied for the test duration, and if the error rate threshold is exceeded, the load is decreased. Conversely, if the error rate threshold is not exceeded, the load is increased, and the DHCP performance is evaluated.
  • slowly
    Maximum DHCP server performance is measured starting with a low load, which is gradually raised. At the start, a load of one transaction per second is applied for the test duration. If the error rate threshold is not exceeded, the load is doubled. Conversely, if the error rate threshold is exceeded, the load is halved, and the DHCP performance is evaluated.
  • endless
    In this form of testing a constant load is applied without stopping.
  • once
    This testing only performs one DHCP server transaction. This testing can be used to confirm connectivity. A return value of "0" indicates connectivity. A return value of "1" indicates a transmission error.

Outputting statistical information

Running the tester with the -v or -progress command line arguments displays statistical information on the standard output device, updated every second.
The following information is output.

  • secs
    Amount of seconds the program has been running.
  • success
    Total number of transaction successes.
  • failure
    Number of NAK responses or timeouts.
  • active
    Number of transactions in-progress or awaiting responses.
  • minimum
    Minimum number of transactions per second.
  • current
    Number of transactions per second.
  • maximum
    Maximum number of transactions per second.
  • average
    Average time from start to end of each transaction. Measured in milliseconds.
  • slowest
    Maximum time from start to end of a transaction. Measured in milliseconds.
  • fastest
    Minimum time from start to end of a transaction. Measured in milliseconds.

Lease renewal testing

Lease renewal, even when performed via a relay.
Testing sample data which includes lease renewal is contained in /usr/share/ncad/dhcpperf/expand.dat, and can be used by using the following command.

./dhcpperf -v -s <DHCP server IP address> <device name> discover.dat request.dat expand.dat release.dat

Date: 2014-12-22

Author: Nippon C.A.D. Co.,Ltd. Products Development Division

Created: 2016-04-01 ้‡‘ 11:50

Emacs 24.4.1 (Org mode 8.0.7)

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