VSPERF Design¶
1. VSPERF Design Document¶
1.1. Intended Audience¶
This document is intended to aid those who want to modify the vsperf code. Or to extend it - for example to add support for new traffic generators, deployment scenarios and so on.
1.2. Usage¶
1.2.1. Example Connectivity to DUT¶
Establish connectivity to the VSPERF DUT Linux host, such as the DUT in Pod 3, by following the steps in Testbed POD3
The steps cover booking the DUT and establishing the VSPERF environment.
1.2.2. Example Command Lines¶
List all the cli options:
$ ./vsperf -h
Run all tests that have tput in their name - phy2phy_tput, pvp_tput etc.:
$ ./vsperf --tests 'tput'
As above but override default configuration with settings in ‘10_custom.conf’.
This is useful as modifying configuration directly in the configuration files
in conf/NN_*.py shows up as changes under git source control:
$ ./vsperf --conf-file=<path_to_custom_conf>/10_custom.conf --tests 'tput'
Override specific test parameters. Useful for shortening the duration of tests for development purposes:
$ ./vsperf --test-params 'TRAFFICGEN_DURATION=10;TRAFFICGEN_RFC2544_TESTS=1;' \
'TRAFFICGEN_PKT_SIZES=(64,)' pvp_tput
1.4. Configuration¶
The conf package contains the configuration files (*.conf) for all system
components, it also provides a settings object that exposes all of these
settings.
Settings are not passed from component to component. Rather they are available globally to all components once they import the conf package.
from conf import settings
...
log_file = settings.getValue('LOG_FILE_DEFAULT')
Settings files (*.conf) are valid python code so can be set to complex
types such as lists and dictionaries as well as scalar types:
first_packet_size = settings.getValue('PACKET_SIZE_LIST')[0]
1.4.1. Configuration Procedure and Precedence¶
Configuration files follow a strict naming convention that allows them to be
processed in a specific order. All the .conf files are named NN_name.conf,
where NN is a decimal number. The files are processed in order from 00_name.conf
to 99_name.conf so that if the name setting is given in both a lower and higher
numbered conf file then the higher numbered file is the effective setting as it
is processed after the setting in the lower numbered file.
The values in the file specified by --conf-file takes precedence over all
the other configuration files and does not have to follow the naming
convention.
1.4.2. Configuration of PATHS dictionary¶
VSPERF uses external tools like Open vSwitch and Qemu for execution of testcases. These tools may be downloaded and built automatically by VSPERF installation scripts or installed manually by user from binary packages. It is also possible to use a combination of both approaches, but it is essential to correctly set paths to all required tools. These paths are stored within a PATHS dictionary, which is evaluated before execution of each testcase, in order to setup testcase specific environment. Values selected for testcase execution are internally stored inside TOOLS dictionary, which is used by VSPERF to execute external tools, load kernel modules, etc.
The default configuration of PATHS dictionary is spread among three different configuration files
to follow logical grouping of configuration options. Basic description of PATHS dictionary
is placed inside conf/00_common.conf. The configuration specific to DPDK and vswitches
is located at conf/02_vswitch.conf. The last part related to the Qemu is defined inside
conf/04_vnf.conf. Default configuration values can be used in case, that all required
tools were downloaded and built automatically by vsperf itself. In case, that some of
tools were installed manually from binary packages, then it will be necessary to modify
the content of PATHS dictionary accordingly.
Dictionary has a specific section of configuration options for every tool type, it means:
PATHS['vswitch']- contains a separete dictionary for each of vswitches supported by VSPEFExample:
PATHS['vswitch'] = { 'OvsDpdkVhost': { ... }, 'OvsVanilla' : { ... }, ... }
PATHS['dpdk']- contains paths to the dpdk sources, kernel modules and tools (e.g. testpmd)Example:
PATHS['dpdk'] = { 'type' : 'src', 'src': { 'path': os.path.join(ROOT_DIR, 'src/dpdk/dpdk/'), 'modules' : ['uio', os.path.join(RTE_TARGET, 'kmod/igb_uio.ko')], 'bind-tool': 'tools/dpdk*bind.py', 'testpmd': os.path.join(RTE_TARGET, 'app', 'testpmd'), }, ... }
PATHS['qemu']- contains paths to the qemu sources and executable fileExample:
PATHS['qemu'] = { 'type' : 'bin', 'bin': { 'qemu-system': 'qemu-system-x86_64' }, ... }
Every section specific to the particular vswitch, dpdk or qemu may contain following types of configuration options:
option
type- is a string, which defines the type of configured paths (‘src’ or ‘bin’) to be selected for a given section:
- value
srcmeans, that VSPERF will use vswitch, DPDK or QEMU built from sources e.g. by execution ofsystems/build_base_machine.shscript during VSPERF installation- value
binmeans, that VSPERF will use vswitch, DPDK or QEMU binaries installed directly in the operating system, e.g. via OS specific packaging systemoption
path- is a string with a valid system path; Its content is checked for existence, prefixed with section name and stored into TOOLS for later use e.g.TOOLS['dpdk_src']orTOOLS['vswitch_src']option
modules- is list of strings with names of kernel modules; Every module name from given list is checked for a ‘.ko’ suffix. In case that it matches and if it is not an absolute path to the module, then module name is prefixed with value ofpathoption defined for the same sectionExample:
""" snippet of PATHS definition from the configuration file: """ PATHS['vswitch'] = { 'OvsVanilla' = { 'type' : 'src', 'src': { 'path': '/tmp/vsperf/src_vanilla/ovs/ovs/', 'modules' : ['datapath/linux/openvswitch.ko'], ... }, ... } ... } """ Final content of TOOLS dictionary used during runtime: """ TOOLS['vswitch_modules'] = ['/tmp/vsperf/src_vanilla/ovs/ovs/datapath/linux/openvswitch.ko']all other options are strings with names and paths to specific tools; If a given string contains a relative path and option
pathis defined for a given section, then string content will be prefixed with content of thepath. Otherwise the name of the tool will be searched within standard system directories. In case that filename contains OS specific wildcards, then they will be expanded to the real path. At the end of the processing, every absolute path will be checked for its existence. In case that temporary path (i.e. path with a_tmpsuffix) does not exist, then log will be written and vsperf will continue. If any other path will not exist, then vsperf execution will be terminated with a runtime error.Example:
""" snippet of PATHS definition from the configuration file: """ PATHS['vswitch'] = { 'OvsDpdkVhost': { 'type' : 'src', 'src': { 'path': '/tmp/vsperf/src_vanilla/ovs/ovs/', 'ovs-vswitchd': 'vswitchd/ovs-vswitchd', 'ovsdb-server': 'ovsdb/ovsdb-server', ... } ... } ... } """ Final content of TOOLS dictionary used during runtime: """ TOOLS['ovs-vswitchd'] = '/tmp/vsperf/src_vanilla/ovs/ovs/vswitchd/ovs-vswitchd' TOOLS['ovsdb-server'] = '/tmp/vsperf/src_vanilla/ovs/ovs/ovsdb/ovsdb-server'
Note: In case that bin type is set for DPDK, then TOOLS['dpdk_src'] will be set to
the value of PATHS['dpdk']['src']['path']. The reason is, that VSPERF uses downloaded
DPDK sources to copy DPDK and testpmd into the GUEST, where testpmd is built. In case,
that DPDK sources are not available, then vsperf will continue with test execution,
but testpmd can’t be used as a guest loopback. This is useful in case, that other guest
loopback applications (e.g. buildin or l2fwd) are used.
Note: In case of RHEL 7.3 OS usage, binary package configuration is required
for Vanilla OVS tests. With the installation of a supported rpm for OVS there is
a section in the conf\10_custom.conf file that can be used.
1.4.3. Configuration of TRAFFIC dictionary¶
TRAFFIC dictionary is used for configuration of traffic generator. Default values
can be found in configuration file conf/03_traffic.conf. These default values
can be modified by (first option has the highest priorty):
Parameterssection of testcase defintion- command line options specified by
--test-paramsargument- custom configuration file
It is to note, that in case of option 1 and 2, it is possible to specify only
values, which should be changed. In case of custom configuration file, it is
required to specify whole TRAFFIC dictionary with its all values or explicitly
call and update() method of TRAFFIC dictionary.
Detailed description of TRAFFIC dictionary items follows:
'traffic_type' - One of the supported traffic types.
E.g. rfc2544_throughput, rfc2544_back2back
or rfc2544_continuous
Data type: str
Default value: "rfc2544_throughput".
'bidir' - Specifies if generated traffic will be full-duplex (True)
or half-duplex (False)
Data type: str
Supported values: "True", "False"
Default value: "False".
'frame_rate' - Defines desired percentage of frame rate used during
continuous stream tests.
Data type: int
Default value: 100.
'multistream' - Defines number of flows simulated by traffic generator.
Value 0 disables multistream feature
Data type: int
Supported values: 0-65535
Default value: 0.
'stream_type' - Stream type is an extension of the "multistream" feature.
If multistream is disabled, then stream type will be
ignored. Stream type defines ISO OSI network layer used
for simulation of multiple streams.
Data type: str
Supported values:
"L2" - iteration of destination MAC address
"L3" - iteration of destination IP address
"L4" - iteration of destination port
of selected transport protocol
Default value: "L4".
'pre_installed_flows'
- Pre-installed flows is an extension of the "multistream"
feature. If enabled, it will implicitly insert a flow
for each stream. If multistream is disabled, then
pre-installed flows will be ignored.
Note: It is supported only for p2p deployment scenario.
Data type: str
Supported values:
"Yes" - flows will be inserted into OVS
"No" - flows won't be inserted into OVS
Default value: "No".
'flow_type' - Defines flows complexity.
Data type: str
Supported values:
"port" - flow is defined by ingress ports
"IP" - flow is defined by ingress ports
and src and dst IP addresses
Default value: "port"
'l2' - A dictionary with l2 network layer details. Supported
values are:
'srcmac' - Specifies source MAC address filled by traffic generator.
NOTE: It can be modified by vsperf in some scenarios.
Data type: str
Default value: "00:00:00:00:00:00".
'dstmac' - Specifies destination MAC address filled by traffic generator.
NOTE: It can be modified by vsperf in some scenarios.
Data type: str
Default value: "00:00:00:00:00:00".
'framesize' - Specifies default frame size. This value should not be
changed directly. It will be overridden during testcase
execution by values specified by list TRAFFICGEN_PKT_SIZES.
Data type: int
Default value: 64
'l3' - A dictionary with l3 network layer details. Supported
values are:
'srcip' - Specifies source MAC address filled by traffic generator.
NOTE: It can be modified by vsperf in some scenarios.
Data type: str
Default value: "1.1.1.1".
'dstip' - Specifies destination MAC address filled by traffic generator.
NOTE: It can be modified by vsperf in some scenarios.
Data type: str
Default value: "90.90.90.90".
'proto' - Specifies deflaut protocol type.
Please check particular traffic generator implementation
for supported protocol types.
Data type: str
Default value: "udp".
'l4' - A dictionary with l4 network layer details. Supported
values are:
'srcport' - Specifies source port of selected transport protocol.
NOTE: It can be modified by vsperf in some scenarios.
Data type: int
Default value: 3000
'dstport' - Specifies destination port of selected transport protocol.
NOTE: It can be modified by vsperf in some scenarios.
Data type: int
Default value: 3001
'vlan' - A dictionary with vlan encapsulation details. Supported
values are:
'enabled' - Specifies if vlan encapsulation should be enabled or
disabled.
Data type: bool
Default value: False
'id' - Specifies vlan id.
Data type: int (NOTE: must fit to 12 bits)
Default value: 0
'priority' - Specifies a vlan priority (PCP header field).
Data type: int (NOTE: must fit to 3 bits)
Default value: 0
'cfi' - Specifies if frames can or cannot be dropped during
congestion (DEI header field).
Data type: int (NOTE: must fit to 1 bit)
Default value: 0
1.4.4. Configuration of GUEST options¶
VSPERF is able to setup scenarios involving a number of VMs in series or in parallel.
All configuration options related to a particular VM instance are defined as
lists and prefixed with GUEST_ label. It is essential, that there is enough
items in all GUEST_ options to cover all VM instances involved in the test.
In case there is not enough items, then VSPERF will use the first item of
particular GUEST_ option to expand the list to required length.
Example of option expansion for 4 VMs:
""" Original values: """ GUEST_SMP = ['2'] GUEST_MEMORY = ['2048', '4096'] """ Values after automatic expansion: """ GUEST_SMP = ['2', '2', '2', '2'] GUEST_MEMORY = ['2048', '4096', '2048', '2048']
First option can contain macros starting with # to generate VM specific values.
These macros can be used only for options of list or str types with GUEST_
prefix.
Example of macros and their expnasion for 2 VMs:
""" Original values: """ GUEST_SHARE_DIR = ['/tmp/qemu#VMINDEX_share'] GUEST_BRIDGE_IP = ['#IP(1.1.1.5)/16'] """ Values after automatic expansion: """ GUEST_SHARE_DIR = ['/tmp/qemu0_share', '/tmp/qemu1_share'] GUEST_BRIDGE_IP = ['1.1.1.5/16', '1.1.1.6/16']
Additional examples are available at 04_vnf.conf.
Note: In case, that macro is detected in the first item of the list, then all other items are ignored and list content is created automatically.
Multiple macros can be used inside one configuration option definition, but macros
cannot be used inside other macros. The only exception is macro #VMINDEX, which
is expanded first and thus it can be used inside other macros.
Following macros are supported:
#VMINDEX- it is replaced by index of VM being executed; This macro is expanded first, so it can be used inside other macros.Example:
GUEST_SHARE_DIR = ['/tmp/qemu#VMINDEX_share']
#MAC(mac_address[, step])- it will iterate givenmac_addresswith optionalstep. In case that step is not defined, then it is set to 1. It means, that first VM will use the value ofmac_address, second VM value ofmac_addressincreased bystep, etc.Example:
GUEST_NICS = [[{'mac' : '#MAC(00:00:00:00:00:01,2)'}]]
#IP(ip_address[, step])- it will iterate givenip_addresswith optionalstep. In case that step is not defined, then it is set to 1. It means, that first VM will use the value ofip_address, second VM value ofip_addressincreased bystep, etc.Example:
GUEST_BRIDGE_IP = ['#IP(1.1.1.5)/16']
#EVAL(expression)- it will evaluate givenexpressionas python code; Only simple expressions should be used. Call of the functions is not supported.Example:
GUEST_CORE_BINDING = [('#EVAL(6+2*#VMINDEX)', '#EVAL(7+2*#VMINDEX)')]
1.4.5. Other Configuration¶
conf.settings also loads configuration from the command line and from the environment.
1.5. PXP Deployment¶
Every testcase uses one of the supported deployment scenarios to setup test environment. The controller responsible for a given scenario configures flows in the vswitch to route traffic among physical interfaces connected to the traffic generator and virtual machines. VSPERF supports several deployments including PXP deployment, which can setup various scenarios with multiple VMs.
These scenarios are realized by VswitchControllerPXP class, which can configure and execute given number of VMs in serial or parallel configurations. Every VM can be configured with just one or an even number of interfaces. In case that VM has more than 2 interfaces, then traffic is properly routed among pairs of interfaces.
Example of traffic routing for VM with 4 NICs in serial configuration:
+------------------------------------------+
| VM with 4 NICs |
| +---------------+ +---------------+ |
| | Application | | Application | |
| +---------------+ +---------------+ |
| ^ | ^ | |
| | v | v |
| +---------------+ +---------------+ |
| | logical ports | | logical ports | |
| | 0 1 | | 2 3 | |
+--+---------------+----+---------------+--+
^ : ^ :
| | | |
: v : v
+-----------+---------------+----+---------------+----------+
| vSwitch | 0 1 | | 2 3 | |
| | logical ports | | logical ports | |
| previous +---------------+ +---------------+ next |
| VM or PHY ^ | ^ | VM or PHY|
| port -----+ +------------+ +---> port |
+-----------------------------------------------------------+
It is also possible to define different number of interfaces for each VM to better simulate real scenarios.
Example of traffic routing for 2 VMs in serial configuration, where 1st VM has 4 NICs and 2nd VM 2 NICs:
+------------------------------------------+ +---------------------+
| 1st VM with 4 NICs | | 2nd VM with 2 NICs |
| +---------------+ +---------------+ | | +---------------+ |
| | Application | | Application | | | | Application | |
| +---------------+ +---------------+ | | +---------------+ |
| ^ | ^ | | | ^ | |
| | v | v | | | v |
| +---------------+ +---------------+ | | +---------------+ |
| | logical ports | | logical ports | | | | logical ports | |
| | 0 1 | | 2 3 | | | | 0 1 | |
+--+---------------+----+---------------+--+ +--+---------------+--+
^ : ^ : ^ :
| | | | | |
: v : v : v
+-----------+---------------+----+---------------+-------+---------------+----------+
| vSwitch | 0 1 | | 2 3 | | 4 5 | |
| | logical ports | | logical ports | | logical ports | |
| previous +---------------+ +---------------+ +---------------+ next |
| VM or PHY ^ | ^ | ^ | VM or PHY|
| port -----+ +------------+ +---------------+ +----> port |
+-----------------------------------------------------------------------------------+
The number of VMs involved in the test and the type of their connection is defined by deployment name as follows:
pvvp[number]- configures scenario with VMs connected in series with optionalnumberof VMs. In case thatnumberis not specified, then 2 VMs will be used.Example of 2 VMs in a serial configuration:
+----------------------+ +----------------------+ | 1st VM | | 2nd VM | | +---------------+ | | +---------------+ | | | Application | | | | Application | | | +---------------+ | | +---------------+ | | ^ | | | ^ | | | | v | | | v | | +---------------+ | | +---------------+ | | | logical ports | | | | logical ports | | | | 0 1 | | | | 0 1 | | +---+---------------+--+ +---+---------------+--+ ^ : ^ : | | | | : v : v +---+---------------+---------+---------------+--+ | | 0 1 | | 3 4 | | | | logical ports | vSwitch | logical ports | | | +---------------+ +---------------+ | | ^ | ^ | | | | +-----------------+ v | | +----------------------------------------+ | | | physical ports | | | | 0 1 | | +---+----------------------------------------+---+ ^ : | | : v +------------------------------------------------+ | | | traffic generator | | | +------------------------------------------------+
pvpv[number]- configures scenario with VMs connected in parallel with optionalnumberof VMs. In case thatnumberis not specified, then 2 VMs will be used. Multistream feature is used to route traffic to particular VMs (or NIC pairs of every VM). It means, that VSPERF will enable multistream feaure and sets the number of streams to the number of VMs and their NIC pairs. Traffic will be dispatched based on Stream Type, i.e. by UDP port, IP address or MAC address.
- Example of 2 VMs in a parallel configuration, where traffic is dispatched
based on the UDP port.
+----------------------+ +----------------------+ | 1st VM | | 2nd VM | | +---------------+ | | +---------------+ | | | Application | | | | Application | | | +---------------+ | | +---------------+ | | ^ | | | ^ | | | | v | | | v | | +---------------+ | | +---------------+ | | | logical ports | | | | logical ports | | | | 0 1 | | | | 0 1 | | +---+---------------+--+ +---+---------------+--+ ^ : ^ : | | | | : v : v +---+---------------+---------+---------------+--+ | | 0 1 | | 3 4 | | | | logical ports | vSwitch | logical ports | | | +---------------+ +---------------+ | | ^ | ^ : | | | ......................: : | | UDP | UDP : | : | | port| port: +--------------------+ : | | 0 | 1 : | : | | | : v v | | +----------------------------------------+ | | | physical ports | | | | 0 1 | | +---+----------------------------------------+---+ ^ : | | : v +------------------------------------------------+ | | | traffic generator | | | +------------------------------------------------+
PXP deployment is backward compatible with PVP deployment, where pvp is
an alias for pvvp1 and it executes just one VM.
The number of interfaces used by VMs is defined by configuration option
GUEST_NICS_NR. In case that more than one pair of interfaces is defined
for VM, then:
- for
pvvp(serial) scenario every NIC pair is connected in serial before connection to next VM is created- for
pvpv(parallel) scenario every NIC pair is directly connected to the physical ports and unique traffic stream is assigned to it
Examples:
- Deployment
pvvp10will start 10 VMs and connects them in series- Deployment
pvpv4will start 4 VMs and connects them in parallel- Deployment
pvpv1and GUEST_NICS_NR = [4] will start 1 VM with 4 interfaces and every NIC pair is directly connected to the physical ports- Deployment
pvvpand GUEST_NICS_NR = [2, 4] will start 2 VMs; 1st VM will have 2 interfaces and 2nd VM 4 interfaces. These interfaces will be connected in serial, i.e. traffic will flow as follows: PHY1 -> VM1_1 -> VM1_2 -> VM2_1 -> VM2_2 -> VM2_3 -> VM2_4 -> PHY2
Note: In case that only 1 or more than 2 NICs are configured for VM,
then testpmd should be used as forwarding application inside the VM.
As it is able to forward traffic between multiple VM NIC pairs.
Note: In case of linux_bridge, all NICs are connected to the same
bridge inside the VM.
1.6. VM, vSwitch, Traffic Generator Independence¶
VSPERF supports different vSwithes, Traffic Generators, VNFs and Forwarding Applications by using standard object-oriented polymorphism:
- Support for vSwitches is implemented by a class inheriting from IVSwitch.
- Support for Traffic Generators is implemented by a class inheriting from ITrafficGenerator.
- Support for VNF is implemented by a class inheriting from IVNF.
- Support for Forwarding Applications is implemented by a class inheriting from IPktFwd.
By dealing only with the abstract interfaces the core framework can support many implementations of different vSwitches, Traffic Generators, VNFs and Forwarding Applications.
1.6.1. IVSwitch¶
class IVSwitch:
start(self)
stop(self)
add_switch(switch_name)
del_switch(switch_name)
add_phy_port(switch_name)
add_vport(switch_name)
get_ports(switch_name)
del_port(switch_name, port_name)
add_flow(switch_name, flow)
del_flow(switch_name, flow=None)
1.6.2. ITrafficGenerator¶
class ITrafficGenerator:
connect()
disconnect()
send_burst_traffic(traffic, numpkts, time, framerate)
send_cont_traffic(traffic, time, framerate)
start_cont_traffic(traffic, time, framerate)
stop_cont_traffic(self):
send_rfc2544_throughput(traffic, tests, duration, lossrate)
start_rfc2544_throughput(traffic, tests, duration, lossrate)
wait_rfc2544_throughput(self)
send_rfc2544_back2back(traffic, tests, duration, lossrate)
start_rfc2544_back2back(traffic, , tests, duration, lossrate)
wait_rfc2544_back2back()
Note send_xxx() blocks whereas start_xxx() does not and must be followed by a subsequent call to wait_xxx().
1.6.3. IVnf¶
class IVnf:
start(memory, cpus,
monitor_path, shared_path_host,
shared_path_guest, guest_prompt)
stop()
execute(command)
wait(guest_prompt)
execute_and_wait (command)
1.6.4. IPktFwd¶
class IPktFwd: start() stop()
1.6.5. Controllers¶
Controllers are used in conjunction with abstract interfaces as way of decoupling the control of vSwtiches, VNFs, TrafficGenerators and Forwarding Applications from other components.
The controlled classes provide basic primitive operations. The Controllers sequence and co-ordinate these primitive operation in to useful actions. For instance the vswitch_controller_p2p can be used to bring any vSwitch (that implements the primitives defined in IVSwitch) into the configuration required by the Phy-to-Phy Deployment Scenario.
In order to support a new vSwitch only a new implementation of IVSwitch needs be created for the new vSwitch to be capable of fulfilling all the Deployment Scenarios provided for by existing or future vSwitch Controllers.
Similarly if a new Deployment Scenario is required it only needs to be written once as a new vSwitch Controller and it will immediately be capable of controlling all existing and future vSwitches in to that Deployment Scenario.
Similarly the Traffic Controllers can be used to co-ordinate basic operations provided by implementers of ITrafficGenerator to provide useful tests. Though traffic generators generally already implement full test cases i.e. they both generate suitable traffic and analyse returned traffic in order to implement a test which has typically been predefined in an RFC document. However the Traffic Controller class allows for the possibility of further enhancement - such as iterating over tests for various packet sizes or creating new tests.
1.6.6. Traffic Controller’s Role¶
1.6.7. Loader & Component Factory¶
The working of the Loader package (which is responsible for finding arbitrary classes based on configuration data) and the Component Factory which is responsible for choosing the correct class for a particular situation - e.g. Deployment Scenario can be seen in this diagram.
1.7. Routing Tables¶
Vsperf uses a standard set of routing tables in order to allow tests to easily mix and match Deployment Scenarios (PVP, P2P topology), Tuple Matching and Frame Modification requirements.
+--------------+
| |
| Table 0 | table#0 - Match table. Flows designed to force 5 & 10
| | tuple matches go here.
| |
+--------------+
|
|
v
+--------------+ table#1 - Routing table. Flow entries to forward
| | packets between ports goes here.
| Table 1 | The chosen port is communicated to subsequent tables by
| | setting the metadata value to the egress port number.
| | Generally this table is set-up by by the
+--------------+ vSwitchController.
|
|
v
+--------------+ table#2 - Frame modification table. Frame modification
| | flow rules are isolated in this table so that they can
| Table 2 | be turned on or off without affecting the routing or
| | tuple-matching flow rules. This allows the frame
| | modification and tuple matching required by the tests
| | in the VSWITCH PERFORMANCE FOR TELCO NFV test
+--------------+ specification to be independent of the Deployment
| Scenario set up by the vSwitchController.
|
v
+--------------+
| |
| Table 3 | table#3 - Egress table. Egress packets on the ports
| | setup in Table 1.
+--------------+
2. Traffic Generator Integration Guide¶
2.1. Intended Audience¶
This document is intended to aid those who want to integrate new traffic generator into the vsperf code. It is expected, that reader has already read generic part of VSPERF Design Document.
Let us create a sample traffic generator called sample_tg, step by step.
2.2. Step 1 - create a directory¶
Implementation of trafficgens is located at tools/pkt_gen/ directory, where every implementation has its dedicated sub-directory. It is required to create a new directory for new traffic generator implementations.
E.g.
$ mkdir tools/pkt_gen/sample_tg
2.3. Step 2 - create a trafficgen module¶
Every trafficgen class must inherit from generic ITrafficGenerator interface class. VSPERF during its initialization scans content of pkt_gen directory for all python modules, that inherit from ITrafficGenerator. These modules are automatically added into the list of supported traffic generators.
Example:
Let us create a draft of tools/pkt_gen/sample_tg/sample_tg.py module.
from tools.pkt_gen import trafficgen
class SampleTG(trafficgen.ITrafficGenerator):
"""
A sample traffic generator implementation
"""
pass
VSPERF is immediately aware of the new class:
$ ./vsperf --list-trafficgen
Output should look like:
Classes derived from: ITrafficGenerator
======
* Ixia: A wrapper around the IXIA traffic generator.
* IxNet: A wrapper around IXIA IxNetwork applications.
* Dummy: A dummy traffic generator whose data is generated by the user.
* SampleTG: A sample traffic generator implementation
* TestCenter: Spirent TestCenter
2.4. Step 3 - configuration¶
All configuration values, required for correct traffic generator function, are passed from VSPERF to the traffic generator in a dictionary. Default values shared among all traffic generators are defined in conf/03_traffic.conf within TRAFFIC dictionary. Default values are loaded by ITrafficGenerator interface class automatically, so it is not needed to load them explicitly. In case that there are any traffic generator specific default values, then they should be set within class specific __init__ function.
VSPERF passes test specific configuration within traffic dictionary to every start and send function. So implementation of these functions must ensure, that default values are updated with the testcase specific values. Proper merge of values is assured by call of merge_spec function from conf module.
Example of merge_spec usage in tools/pkt_gen/sample_tg/sample_tg.py module:
from conf import merge_spec
def start_rfc2544_throughput(self, traffic=None, duration=30):
self._params = {}
self._params['traffic'] = self.traffic_defaults.copy()
if traffic:
self._params['traffic'] = merge_spec(
self._params['traffic'], traffic)
2.5. Step 4 - generic functions¶
There are some generic functions, which every traffic generator should provide. Although these functions are mainly optional, at least empty implementation must be provided. This is required, so that developer is explicitly aware of these functions.
The connect function is called from the traffic generator controller from its __enter__ method. This function should assure proper connection initialization between DUT and traffic generator. In case, that such implementation is not needed, empty implementation is required.
The disconnect function should perform clean up of any connection specific actions called from the connect function.
Example in tools/pkt_gen/sample_tg/sample_tg.py module:
def connect(self):
pass
def disconnect(self):
pass
2.6. Step 5 - supported traffic types¶
Currently VSPERF supports three different types of tests for traffic generators, these are identified in vsperf through the traffic type, which include:
- RFC2544 throughput - Send fixed size packets at different rates, using
- traffic configuration, until minimum rate at which no packet loss is detected is found. Methods with its implementation have suffix _rfc2544_throughput.
- RFC2544 back2back - Send fixed size packets at a fixed rate, using traffic
- configuration, for specified time interval. Methods with its implementation have suffix _rfc2544_back2back.
- continuous flow - Send fixed size packets at given framerate, using traffic
- configuration, for specified time interval. Methods with its implementation have suffix _cont_traffic.
In general, both synchronous and asynchronous interfaces must be implemented for each traffic type. Synchronous functions start with prefix send_. Asynchronous with prefixes start_ and wait_ in case of throughput and back2back and start_ and stop_ in case of continuous traffic type.
Example of synchronous interfaces:
def send_rfc2544_throughput(self, traffic=None, tests=1, duration=20,
lossrate=0.0):
def send_rfc2544_back2back(self, traffic=None, tests=1, duration=20,
lossrate=0.0):
def send_cont_traffic(self, traffic=None, duration=20):
Example of asynchronous interfaces:
def start_rfc2544_throughput(self, traffic=None, tests=1, duration=20,
lossrate=0.0):
def wait_rfc2544_throughput(self):
def start_rfc2544_back2back(self, traffic=None, tests=1, duration=20,
lossrate=0.0):
def wait_rfc2544_back2back(self):
def start_cont_traffic(self, traffic=None, duration=20):
def stop_cont_traffic(self):
Description of parameters used by send, start, wait and stop functions:
param traffic: A dictionary with detailed definition of traffic pattern. It contains following parameters to be implemented by traffic generator.
Note: Traffic dictionary has also virtual switch related parameters, which are not listed below.
Note: There are parameters specific to testing of tunnelling protocols, which are discussed in detail at integration tests userguide
- param traffic_type: One of the supported traffic types, e.g. rfc2544_throughput, rfc2544_continuous or rfc2544_back2back.
- param frame_rate: Defines desired percentage of frame rate used during continuous stream tests.
- param bidir: Specifies if generated traffic will be full-duplex (true) or half-duplex (false).
- param multistream: Defines number of flows simulated by traffic generator. Value 0 disables MultiStream feature.
- param stream_type: Stream Type defines ISO OSI network layer used for simulation of multiple streams. Supported values:
- L2 - iteration of destination MAC address
- L3 - iteration of destination IP address
- L4 - iteration of destination port of selected transport protocol
- param l2: A dictionary with data link layer details, e.g. srcmac, dstmac and framesize.
- param l3: A dictionary with network layer details, e.g. srcip, dstip and proto.
- param l3: A dictionary with transport layer details, e.g. srcport, dstport.
- param vlan: A dictionary with vlan specific parameters, e.g. priority, cfi, id and vlan on/off switch enabled.
param tests: Number of times the test is executed.
param duration: Duration of continuous test or per iteration duration in case of RFC2544 throughput or back2back traffic types.
param lossrate: Acceptable lossrate percentage.
2.7. Step 6 - passing back results¶
It is expected that methods send, wait and stop will return values measured by traffic generator within a dictionary. Dictionary keys are defined in ResultsConstants implemented in core/results/results_constants.py. Please check sections for RFC2544 Throughput & Continuous and for Back2Back. The same key names should be used by all traffic generator implementations.
