Internet Engineering Task Force (IETF) B. Constantine
Request for Comments: 7640 JDSU
Category: Informational R. Krishnan
ISSN: 2070-1721 Dell Inc.
September 2015
Traffic Management Benchmarking
Abstract
This framework describes a practical methodology for benchmarking the
traffic management capabilities of networking devices (i.e.,
policing, shaping, etc.). The goals are to provide a repeatable test
method that objectively compares performance of the device's traffic
management capabilities and to specify the means to benchmark traffic
management with representative application traffic.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7640.
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Table of Contents
1. Introduction ....................................................3
1.1. Traffic Management Overview ................................3
1.2. Lab Configuration and Testing Overview .....................5
2. Conventions Used in This Document ...............................6
3. Scope and Goals .................................................7
4. Traffic Benchmarking Metrics ...................................10
4.1. Metrics for Stateless Traffic Tests .......................10
4.2. Metrics for Stateful Traffic Tests ........................12
5. Tester Capabilities ............................................13
5.1. Stateless Test Traffic Generation .........................13
5.1.1. Burst Hunt with Stateless Traffic ..................14
5.2. Stateful Test Pattern Generation ..........................14
5.2.1. TCP Test Pattern Definitions .......................15
6. Traffic Benchmarking Methodology ...............................17
6.1. Policing Tests ............................................17
6.1.1. Policer Individual Tests ...........................18
6.1.2. Policer Capacity Tests .............................19
6.1.2.1. Maximum Policers on Single Physical Port ..20
6.1.2.2. Single Policer on All Physical Ports ......22
6.1.2.3. Maximum Policers on All Physical Ports ....22
6.2. Queue/Scheduler Tests .....................................23
6.2.1. Queue/Scheduler Individual Tests ...................23
6.2.1.1. Testing Queue/Scheduler with
Stateless Traffic .........................23
6.2.1.2. Testing Queue/Scheduler with
Stateful Traffic ..........................25
6.2.2. Queue/Scheduler Capacity Tests .....................28
6.2.2.1. Multiple Queues, Single Port Active .......28
6.2.2.1.1. Strict Priority on
Egress Port ....................28
6.2.2.1.2. Strict Priority + WFQ on
Egress Port ....................29
6.2.2.2. Single Queue per Port, All Ports Active ...30
6.2.2.3. Multiple Queues per Port, All
Ports Active ..............................31
6.3. Shaper Tests ..............................................32
6.3.1. Shaper Individual Tests ............................32
6.3.1.1. Testing Shaper with Stateless Traffic .....33
6.3.1.2. Testing Shaper with Stateful Traffic ......34
6.3.2. Shaper Capacity Tests ..............................36
6.3.2.1. Single Queue Shaped, All Physical
Ports Active ..............................37
6.3.2.2. All Queues Shaped, Single Port Active .....37
6.3.2.3. All Queues Shaped, All Ports Active .......39
6.4. Concurrent Capacity Load Tests ............................40
7. Security Considerations ........................................40
8. References .....................................................41
8.1. Normative References ......................................41
8.2. Informative References ....................................42
Appendix A. Open Source Tools for Traffic Management Testing ......44
Appendix B. Stateful TCP Test Patterns ............................45
Acknowledgments ...................................................51
Authors' Addresses ................................................51
1. Introduction
Traffic management (i.e., policing, shaping, etc.) is an increasingly
important component when implementing network Quality of Service
(QoS).
There is currently no framework to benchmark these features, although
some standards address specific areas as described in Section 1.1.
This document provides a framework to conduct repeatable traffic
management benchmarks for devices and systems in a lab environment.
Specifically, this framework defines the methods to characterize the
capacity of the following traffic management features in network
devices: classification, policing, queuing/scheduling, and traffic
shaping.
This benchmarking framework can also be used as a test procedure to
assist in the tuning of traffic management parameters before service
activation. In addition to Layer 2/3 (Ethernet/IP) benchmarking,
Layer 4 (TCP) test patterns are proposed by this document in order to
more realistically benchmark end-user traffic.
1.1. Traffic Management Overview
In general, a device with traffic management capabilities performs
the following functions:
- Traffic classification: identifies traffic according to various
configuration rules (for example, IEEE 802.1Q Virtual LAN (VLAN),
Differentiated Services Code Point (DSCP)) and marks this traffic
internally to the network device. Multiple external priorities
(DSCP, 802.1p, etc.) can map to the same priority in the device.
- Traffic policing: limits the rate of traffic that enters a network
device according to the traffic classification. If the traffic
exceeds the provisioned limits, the traffic is either dropped or
remarked and forwarded onto the next network device.
- Traffic scheduling: provides traffic classification within the
network device by directing packets to various types of queues and
applies a dispatching algorithm to assign the forwarding sequence
of packets.
- Traffic shaping: controls traffic by actively buffering and
smoothing the output rate in an attempt to adapt bursty traffic to
the configured limits.
- Active Queue Management (AQM): involves monitoring the status of
internal queues and proactively dropping (or remarking) packets,
which causes hosts using congestion-aware protocols to "back off"
and in turn alleviate queue congestion [RFC7567]. On the other
hand, classic traffic management techniques reactively drop (or
remark) packets based on queue-full conditions. The benchmarking
scenarios for AQM are different and are outside the scope of this
testing framework.
Even though AQM is outside the scope of this framework, it should be
noted that the TCP metrics and TCP test patterns (defined in
Sections 4.2 and 5.2, respectively) could be useful to test new AQM
algorithms (targeted to alleviate "bufferbloat"). Examples of these
algorithms include Controlled Delay [CoDel] and Proportional Integral
controller Enhanced [PIE].
The following diagram is a generic model of the traffic management
capabilities within a network device. It is not intended to
represent all variations of manufacturer traffic management
capabilities, but it provides context for this test framework.
|----------| |----------------| |--------------| |----------|
| | | | | | | |
|Interface | |Ingress Actions | |Egress Actions| |Interface |
|Ingress | |(classification,| |(scheduling, | |Egress |
|Queues | | marking, | | shaping, | |Queues |
| |-->| policing, or |-->| active queue |-->| |
| | | shaping) | | management, | | |
| | | | | remarking) | | |
|----------| |----------------| |--------------| |----------|
Figure 1: Generic Traffic Management Capabilities of a Network Device
Ingress actions such as classification are defined in [RFC4689] and
include IP addresses, port numbers, and DSCP. In terms of marking,
[RFC2697] and [RFC2698] define a Single Rate Three Color Marker and a
Two Rate Three Color Marker, respectively.
The Metro Ethernet Forum (MEF) specifies policing and shaping in
terms of ingress and egress subscriber/provider conditioning
functions as described in MEF 12.1 [MEF-12.1], 12.2 [MEF-12.2], as well as ingress and
bandwidth profile attributes as described in MEF 10.2 [MEF-10.2] 10.3 [MEF-10.3] and
MEF 26 [MEF-26]. 26.1 [MEF-26.1].
1.2. Lab Configuration and Testing Overview
The following diagram shows the lab setup for the traffic management
tests:
+--------------+ +-------+ +----------+ +-----------+
| Transmitting | | | | | | Receiving |
| Test Host | | | | | | Test Host |
| |-----| Device|---->| Network |--->| |
| | | Under | | Delay | | |
| | | Test | | Emulator | | |
| |<----| |<----| |<---| |
| | | | | | | |
+--------------+ +-------+ +----------+ +-----------+
Figure 2: Lab Setup for Traffic Management Tests
As shown in the test diagram, the framework supports unidirectional
and bidirectional traffic management tests (where the transmitting
and receiving roles would be reversed on the return path).
This testing framework describes the tests and metrics for each of
the following traffic management functions:
- Classification
- Policing
- Queuing/scheduling
- Shaping
The tests are divided into individual and rated capacity tests. The
individual tests are intended to benchmark the traffic management
functions according to the metrics defined in Section 4. The
capacity tests verify traffic management functions under the load of
many simultaneous individual tests and their flows.
This involves concurrent testing of multiple interfaces with the
specific traffic management function enabled, and increasing the load
to the capacity limit of each interface.
For example, a device is specified to be capable of shaping on all of
its egress ports. The individual test would first be conducted to
benchmark the specified shaping function against the metrics defined
in Section 4. Then, the capacity test would be executed to test the
shaping function concurrently on all interfaces and with maximum
traffic load.
The Network Delay Emulator (NDE) is required for TCP stateful tests
in order to allow TCP to utilize a TCP window of significant size in
its control loop.
Note also that the NDE SHOULD be passive in nature (e.g., a fiber
spool). This is recommended to eliminate the potential effects that
an active delay element (i.e., test impairment generator) may have on
the test flows. In the case where a fiber spool is not practical due
to the desired latency, an active NDE MUST be independently verified
to be capable of adding the configured delay without loss. In other
words, the Device Under Test (DUT) would be removed and the NDE
performance benchmarked independently.
Note that the NDE SHOULD be used only as emulated delay. Most NDEs
allow for per-flow delay actions, emulating QoS prioritization. For
this framework, the NDE's sole purpose is simply to add delay to all
packets (emulate network latency). So, to benchmark the performance
of the NDE, the maximum offered load should be tested against the
following frame sizes: 128, 256, 512, 768, 1024, 1500, and
9600 bytes. The delay accuracy at each of these packet sizes can
then be used to calibrate the range of expected Bandwidth-Delay
Product (BDP) for the TCP stateful tests.
2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
The following acronyms are used:
AQM: Active Queue Management
BB: Bottleneck Bandwidth
BDP: Bandwidth-Delay Product
BSA: Burst Size Achieved
CBS: Committed Burst Size
CIR: Committed Information Rate
DUT: Device Under Test
EBS: Excess Burst Size
EIR: Excess Information Rate
NDE: Network Delay Emulator
QL: Queue Length
QoS: Quality of Service
RTT: Round-Trip Time
SBB: Shaper Burst Bytes
SBI: Shaper Burst Interval
SP: Strict Priority
SR: Shaper Rate
SSB: Send Socket Buffer
SUT: System Under Test
Ti: Transmission Interval
TTP: TCP Test Pattern
TTPET: TCP Test Pattern Execution Time
3. Scope and Goals
The scope of this work is to develop a framework for benchmarking and
testing the traffic management capabilities of network devices in the
lab environment. These network devices may include but are not
limited to:
- Switches (including Layer 2/3 devices)
- Routers
- Firewalls
- General Layer 4-7 appliances (Proxies, WAN Accelerators, etc.)
Essentially, any network device that performs traffic management as
defined in Section 1.1 can be benchmarked or tested with this
framework.
The primary goal is to assess the maximum forwarding performance
deemed to be within the provisioned traffic limits that a network
device can sustain without dropping or impairing packets, and without
compromising the accuracy of multiple instances of traffic management
functions. This is the benchmark for comparison between devices.
Within this framework, the metrics are defined for each traffic
management test but do not include pass/fail criteria, which are not
within the charter of the BMWG. This framework provides the test
methods and metrics to conduct repeatable testing, which will provide
the means to compare measured performance between DUTs.
As mentioned in Section 1.2, these methods describe the individual
tests and metrics for several management functions. It is also
within scope that this framework will benchmark each function in
terms of overall rated capacity. This involves concurrent testing of
multiple interfaces with the specific traffic management function
enabled, up to the capacity limit of each interface.
It is not within the scope of this framework to specify the procedure
for testing multiple configurations of traffic management functions
concurrently. The multitudes of possible combinations are almost
unbounded, and the ability to identify functional "break points"
would be almost impossible.
However, Section 6.4 provides suggestions for some profiles of
concurrent functions that would be useful to benchmark. The key
requirement for any concurrent test function is that tests MUST
produce reliable and repeatable results.
Also, it is not within scope to perform conformance testing. Tests
defined in this framework benchmark the traffic management functions
according to the metrics defined in Section 4 and do not address any
conformance to standards related to traffic management.
The current specifications don't specify exact behavior or
implementation, and the specifications that do exist (cited in
Section 1.1) allow implementations to vary with regard to short-term
rate accuracy and other factors. This is a primary driver for this
framework: to provide an objective means to compare vendor traffic
management functions.
Another goal is to devise methods that utilize flows with congestion-
aware transport (TCP) as part of the traffic load and still produce
repeatable results in the isolated test environment. This framework
will derive stateful test patterns (TCP or application layer) that
can also be used to further benchmark the performance of applicable
traffic management techniques such as queuing/scheduling and traffic
shaping. In cases where the network device is stateful in nature
(i.e., firewall, etc.), stateful test pattern traffic is important to
test, along with stateless UDP traffic in specific test scenarios
(i.e., applications using TCP transport and UDP VoIP, etc.).
As mentioned earlier in this document, repeatability of test results
is critical, especially considering the nature of stateful TCP
traffic. To this end, the stateful tests will use TCP test patterns
to emulate applications. This framework also provides guidelines for
application modeling and open source tools to achieve the repeatable
stimulus. Finally, TCP metrics from [RFC6349] MUST be measured for
each stateful test and provide the means to compare each repeated
test.
Even though this framework targets the testing of TCP applications
(i.e., web, email, database, etc.), it could also be applied to the
Stream Control Transmission Protocol (SCTP) in terms of test
patterns. WebRTC, Signaling System 7 (SS7) signaling, and 3GPP are
SCTP-based applications that could be modeled with this framework to
benchmark SCTP's effect on traffic management performance.
Note that at the time of this writing, this framework does not
address tcpcrypt (encrypted TCP) test patterns, although the metrics
defined in Section 4.2 can still be used because the metrics are
based on TCP retransmission and RTT measurements (versus any of the
payload). Thus, if tcpcrypt becomes popular, it would be natural for
benchmarkers to consider encrypted TCP patterns and include them in
test cases.
4. Traffic Benchmarking Metrics
The metrics to be measured during the benchmarks are divided into two
(2) sections: packet-layer metrics used for the stateless traffic
testing and TCP-layer metrics used for the stateful traffic testing.
4.1. Metrics for Stateless Traffic Tests
Stateless traffic measurements require that a sequence number and
timestamp be inserted into the payload for lost-packet analysis.
Delay analysis may be achieved by insertion of timestamps directly
into the packets or timestamps stored elsewhere (packet captures).
This framework does not specify the packet format to carry sequence
number or timing information.
However, [RFC4737] and [RFC4689] provide recommendations for sequence
tracking, along with definitions of in-sequence and out-of-order
packets.
The following metrics MUST be measured during the stateless traffic
benchmarking components of the tests:
- Burst Size Achieved (BSA): For the traffic policing and network
queue tests, the tester will be configured to send bursts to test
either the Committed Burst Size (CBS) or Excess Burst Size (EBS)
of a policer or the queue/buffer size configured in the DUT. The
BSA metric is a measure of the actual burst size received at the
egress port of the DUT with no lost packets. For example, the
configured CBS of a DUT is 64 KB, and after the burst test, only a
63 KB burst can be achieved without packet loss. Then, 63 KB is
the BSA. Also, the average Packet Delay Variation (PDV) (see
below) as experienced by the packets sent at the BSA burst size
should be recorded. This metric SHALL be reported in units of
bytes, KB, or MB.
- Lost Packets (LP): For all traffic management tests, the tester
will transmit the test packets into the DUT ingress port, and the
number of packets received at the egress port will be measured.
The difference between packets transmitted into the ingress port
and received at the egress port is the number of lost packets as
measured at the egress port. These packets must have unique
identifiers such that only the test packets are measured. For
cases where multiple flows are transmitted from the ingress port
to the egress port (e.g., IP conversations), each flow must have
sequence numbers within the stream of test packets.
[RFC6703] and [RFC2680] describe the need to establish the time
threshold to wait before a packet is declared as lost. This
threshold MUST be reported, with the results reported as an integer
number that cannot be negative.
- Out-of-Sequence (OOS): In addition to the LP metric, the test
packets must be monitored for sequence. [RFC4689] defines the
general function of sequence tracking, as well as definitions for
in-sequence and out-of-order packets. Out-of-order packets will
be counted per [RFC4737]. This metric SHALL be reported as an
integer number that cannot be negative.
- Packet Delay (PD): The PD metric is the difference between the
timestamp of the received egress port packets and the packets
transmitted into the ingress port, as specified in [RFC1242]. The
transmitting host and receiving host time must be in time sync
(achieved by using NTP, GPS, etc.). This metric SHALL be reported
as a real number of seconds, where a negative measurement usually
indicates a time synchronization problem between test devices.
- Packet Delay Variation (PDV): The PDV metric is the variation
between the timestamp of the received egress port packets, as
specified in [RFC5481]. Note that per [RFC5481], this PDV is the
variation of one-way delay across many packets in the traffic
flow. Per the measurement formula in [RFC5481], select the high
percentile of 99%, and units of measure will be a real number of
seconds (a negative value is not possible for the PDV and would
indicate a measurement error).
- Shaper Rate (SR): The SR represents the average DUT output rate
(bps) over the test interval. The SR is only applicable to the
traffic-shaping tests.
- Shaper Burst Bytes (SBB): A traffic shaper will emit packets in
"trains" of different sizes; these frames are emitted "back-to-
back" with respect to the mandatory interframe gap. This metric
characterizes the method by which the shaper emits traffic. Some
shapers transmit larger bursts per interval, and a burst of
one packet would apply to the less common case of a shaper sending
a constant-bitrate stream of single packets. This metric SHALL be
reported in units of bytes, KB, or MB. The SBB metric is only
applicable to the traffic-shaping tests.
- Shaper Burst Interval (SBI): The SBI is the time between bursts
emitted by the shaper and is measured at the DUT egress port.
This metric SHALL be reported as a real number of seconds. The
SBI is only applicable to the traffic-shaping tests.
4.2. Metrics for Stateful Traffic Tests
The stateful metrics will be based on [RFC6349] TCP metrics and MUST
include:
- TCP Test Pattern Execution Time (TTPET): [RFC6349] defined the TCP
Transfer Time for bulk transfers, which is simply the measured
time to transfer bytes across single or concurrent TCP
connections. The TCP test patterns used in traffic management
tests will include bulk transfer and interactive applications.
The interactive patterns include instances such as HTTP business
applications and database applications. The TTPET will be the
measure of the time for a single execution of a TCP Test Pattern
(TTP). Average, minimum, and maximum times will be measured or
calculated and expressed as a real number of seconds.
An example would be an interactive HTTP TTP session that should take
5 seconds on a GigE network with 0.5-millisecond latency. During ten
(10) executions of this TTP, the TTPET results might be an average of
6.5 seconds, a minimum of 5.0 seconds, and a maximum of 7.9 seconds.
- TCP Efficiency: After the execution of the TTP, TCP Efficiency
represents the percentage of bytes that were not retransmitted.
Transmitted Bytes - Retransmitted Bytes
TCP Efficiency % = --------------------------------------- X 100
Transmitted Bytes
"Transmitted Bytes" is the total number of TCP bytes to be
transmitted, including the original bytes and the retransmitted
bytes. To avoid any misinterpretation that a reordered packet is a
retransmitted packet (as may be the case with packet decode
interpretation), these retransmitted bytes should be recorded from
the perspective of the sender's TCP/IP stack.
- Buffer Delay: Buffer Delay represents the increase in RTT during a
TCP test versus the baseline DUT RTT (non-congested, inherent
latency). RTT and the technique to measure RTT (average versus
baseline) are defined in [RFC6349]. Referencing [RFC6349], the
average RTT is derived from the total of all measured RTTs during
the actual test sampled at every second divided by the test
duration in seconds.
Total RTTs during transfer
Average RTT during transfer = ------------------------------
Transfer duration in seconds
Average RTT during transfer - Baseline RTT
Buffer Delay % = ------------------------------------------ X 100
Baseline RTT
Note that even though this was not explicitly stated in [RFC6349],
retransmitted packets should not be used in RTT measurements.
Also, the test results should record the average RTT in milliseconds
across the entire test duration, as well as the number of samples.
5. Tester Capabilities
The testing capabilities of the traffic management test environment
are divided into two (2) sections: stateless traffic testing and
stateful traffic testing.
5.1. Stateless Test Traffic Generation
The test device MUST be capable of generating traffic at up to the
link speed of the DUT. The test device must be calibrated to verify
that it will not drop any packets. The test device's inherent PD and
PDV must also be calibrated and subtracted from the PD and PDV
metrics. The test device must support the encapsulation to be
tested, e.g., IEEE 802.1Q VLAN, IEEE 802.1ad Q-in-Q, Multiprotocol
Label Switching (MPLS). Also, the test device must allow control of
the classification techniques defined in [RFC4689] (e.g., IP address,
DSCP, classification of Type of Service).
The open source tool "iperf" can be used to generate stateless UDP
traffic and is discussed in Appendix A. Since iperf is a software-
based tool, there will be performance limitations at higher link
speeds (e.g., 1 GigE, 10 GigE). Careful calibration of any test
environment using iperf is important. At higher link speeds, using
hardware-based packet test equipment is recommended.
5.1.1. Burst Hunt with Stateless Traffic
A central theme for the traffic management tests is to benchmark the
specified burst parameter of a traffic management function, since
burst parameters listed in Service Level Agreements (SLAs) are
specified in bytes. For testing efficiency, including a burst hunt
feature is recommended, as this feature automates the manual process
of determining the maximum burst size that can be supported by a
traffic management function.
The burst hunt algorithm should start at the target burst size
(maximum burst size supported by the traffic management function) and
will send single bursts until it can determine the largest burst that
can pass without loss. If the target burst size passes, then the
test is complete. The "hunt" aspect occurs when the target burst
size is not achieved; the algorithm will drop down to a configured
minimum burst size and incrementally increase the burst until the
maximum burst supported by the DUT is discovered. The recommended
granularity of the incremental burst size increase is 1 KB.
For a policer function, if the burst size passes, the burst should be
increased by increments of 1 KB to verify that the policer is truly
configured properly (or enabled at all).
5.2. Stateful Test Pattern Generation
The TCP test host will have many of the same attributes as the TCP
test host defined in [RFC6349]. The TCP test device may be a
standard computer or a dedicated communications test instrument. In
both cases, it must be capable of emulating both a client and a
server.
For any test using stateful TCP test traffic, the Network Delay
Emulator (the NDE function as shown in the lab setup diagram in
Section 1.2) must be used in order to provide a meaningful BDP. As
discussed in Section 1.2, the target traffic rate and configured RTT
MUST be verified independently, using just the NDE for all stateful
tests (to ensure that the NDE can add delay without inducing any
packet loss).
The TCP test host MUST be capable of generating and receiving
stateful TCP test traffic at the full link speed of the DUT. As a
general rule of thumb, testing TCP throughput at rates greater than
500 Mbps may require high-performance server hardware or dedicated
hardware-based test tools.
The TCP test host MUST allow the adjustment of both Send and Receive
Socket Buffer sizes. The Socket Buffers must be large enough to fill
the BDP for bulk transfer of TCP test application traffic.
Measuring RTT and retransmissions per connection will generally
require a dedicated communications test instrument. In the absence
of dedicated hardware-based test tools, these measurements may need
to be conducted with packet capture tools; i.e., conduct TCP
throughput tests, and analyze RTT and retransmissions in packet
captures.
The TCP implementation used by the test host MUST be specified in the
test results (e.g., TCP New Reno, TCP options supported).
Additionally, the test results SHALL provide specific congestion
control algorithm details, as per [RFC3148].
While [RFC6349] defined the means to conduct throughput tests of TCP
bulk transfers, the traffic management framework will extend TCP test
execution into interactive TCP application traffic. Examples include
email, HTTP, and business applications. This interactive traffic is
bidirectional and can be chatty, meaning many turns in traffic
communication during the course of a transaction (versus the
relatively unidirectional flow of bulk transfer applications).
The test device must not only support bulk TCP transfer application
traffic but MUST also support chatty traffic. A valid stress test
SHOULD include both traffic types. This is due to the non-uniform,
bursty nature of chatty applications versus the relatively uniform
nature of bulk transfers (the bulk transfer smoothly stabilizes to
equilibrium state under lossless conditions).
While iperf is an excellent choice for TCP bulk transfer testing, the
"netperf" open source tool provides the ability to control client and
server request/response behavior. The netperf-wrapper tool is a
Python script that runs multiple simultaneous netperf instances and
aggregates the results. Appendix A provides an overview of
netperf/netperf-wrapper, as well as iperf. As with any software-
based tool, the performance must be qualified to the link speed to be
tested. Hardware-based test equipment should be considered for
reliable results at higher link speeds (e.g., 1 GigE, 10 GigE).
5.2.1. TCP Test Pattern Definitions
As mentioned in the goals of this framework, techniques are defined
to specify TCP traffic test patterns to benchmark traffic management
technique(s) and produce repeatable results. Some network devices,
such as firewalls, will not process stateless test traffic; this is
another reason why stateful TCP test traffic must be used.
An application could be fully emulated up to Layer 7; however, this
framework proposes that stateful TCP test patterns be used in order
to provide granular and repeatable control for the benchmarks. The
following diagram illustrates a simple web-browsing application
(HTTP).
GET URL
Client -------------------------> Web
|
Web 200 OK 100 ms |
|
Browser <------------------------- Server
Figure 3: Simple Flow Diagram for a Web Application
In this example, the Client Web Browser (client) requests a URL, and
then the Web Server delivers the web page content to the client
(after a server delay of 100 milliseconds). This asynchronous
"request/response" behavior is intrinsic to most TCP-based
applications, such as email (SMTP), file transfers (FTP and Server
Message Block (SMB)), database (SQL), web applications (SOAP), and
Representational State Transfer (REST). The impact on the network
elements is due to the multitudes of clients and the variety of
bursty traffic, which stress traffic management functions. The
actual emulation of the specific application protocols is not
required, and TCP test patterns can be defined to mimic the
application network traffic flows and produce repeatable results.
Application modeling techniques have been proposed in
[3GPP2-C_R1002-A], which provides examples to model the behavior of
HTTP, FTP, and Wireless Application Protocol (WAP) applications at
the TCP layer. The models have been defined with various
mathematical distributions for the request/response bytes and
inter-request gap times. The model definition formats described in
[3GPP2-C_R1002-A] are the basis for the guidelines provided in
Appendix B and are also similar to formats used by network modeling
tools. Packet captures can also be used to characterize application
traffic and specify some of the test patterns listed in Appendix B.
This framework does not specify a fixed set of TCP test patterns but
does provide test cases that SHOULD be performed; see Appendix B.
Some of these examples reflect those specified in [CA-Benchmark],
which suggests traffic mixes for a variety of representative
application profiles. Other examples are simply well-known
application traffic types such as HTTP.
6. Traffic Benchmarking Methodology
The traffic benchmarking methodology uses the test setup from
Section 1.2 and metrics defined in Section 4.
Each test SHOULD compare the network device's internal statistics
(available via command line management interface, SNMP, etc.) to the
measured metrics defined in Section 4. This evaluates the accuracy
of the internal traffic management counters under individual test
conditions and capacity test conditions as defined in Sections 4.1
and 4.2. This comparison is not intended to compare real-time
statistics, but rather the cumulative statistics reported after the
test has completed and device counters have updated (it is common for
device counters to update after an interval of 10 seconds or more).
From a device configuration standpoint, scheduling and shaping
functionality can be applied to logical ports (e.g., Link Aggregation
(LAG)). This would result in the same scheduling and shaping
configuration applied to all of the member physical ports. The focus
of this document is only on tests at a physical-port level.
The following sections provide the objective, procedure, metrics, and
reporting format for each test. For all test steps, the following
global parameters must be specified:
Test Runs (Tr):
The number of times the test needs to be run to ensure accurate
and repeatable results. The recommended value is a minimum
of 10.
Test Duration (Td):
The duration of a test iteration, expressed in seconds. The
recommended minimum value is 60 seconds.
The variability in the test results MUST be measured between test
runs, and if the variation is characterized as a significant portion
of the measured values, the next step may be to revise the methods to
achieve better consistency.
6.1. Policing Tests
A policer is defined as the entity performing the policy function.
The intent of the policing tests is to verify the policer performance
(i.e., CIR/CBS and EIR/EBS parameters). The tests will verify that
the network device can handle the CIR with CBS and the EIR with EBS,
and will use back-to-back packet-testing concepts as described in
[RFC2544] (but adapted to burst size algorithms and terminology).
Also, [MEF-14], [MEF-19], and [MEF-37] provide some bases for
specific components of this test. The burst hunt algorithm defined
in Section 5.1.1 can also be used to automate the measurement of the
CBS value.
The tests are divided into two (2) sections: individual policer tests
and then full-capacity policing tests. It is important to benchmark
the basic functionality of the individual policer and then proceed
into the fully rated capacity of the device. This capacity may
include the number of policing policies per device and the number of
policers simultaneously active across all ports.
6.1.1. Policer Individual Tests
Objective:
Test a policer as defined by [RFC4115] or [MEF-10.2], [MEF-10.3], depending
upon the equipment's specification. In addition to verifying that
the policer allows the specified CBS and EBS bursts to pass, the
policer test MUST verify that the policer will remark or drop
excess packets, and pass traffic at the specified CBS/EBS values.
Test Summary:
Policing tests should use stateless traffic. Stateful TCP test
traffic will generally be adversely affected by a policer in the
absence of traffic shaping. So, while TCP traffic could be used,
it is more accurate to benchmark a policer with stateless traffic.
As an example of a policer as defined by [RFC4115], consider a
CBS/EBS of 64 KB and CIR/EIR of 100 Mbps on a 1 GigE physical link
(in color-blind mode). A stateless traffic burst of 64 KB would
be sent into the policer at the GigE rate. This equates to an
approximately 0.512-millisecond burst time (64 KB at 1 GigE). The
traffic generator must space these bursts to ensure that the
aggregate throughput does not exceed the CIR. The Ti between the
bursts would equal CBS * 8 / CIR = 5.12 milliseconds in this
example.
Test Metrics:
The metrics defined in Section 4.1 (BSA, LP, OOS, PD, and PDV)
SHALL be measured at the egress port and recorded.
Procedure:
1. Configure the DUT policing parameters for the desired CIR/EIR
and CBS/EBS values to be tested.
2. Configure the tester to generate a stateless traffic burst
equal to CBS and an interval equal to Ti (CBS in bits/CIR).
3. Compliant Traffic Test: Generate bursts of CBS + EBS traffic
into the policer ingress port, and measure the metrics defined
in Section 4.1 (BSA, LP, OOS, PD, and PDV) at the egress port
and across the entire Td (default 60-second duration).
4. Excess Traffic Test: Generate bursts of greater than CBS + EBS
bytes into the policer ingress port, and verify that the
policer only allowed the BSA bytes to exit the egress. The
excess burst MUST be recorded; the recommended value is
1000 bytes. Additional tests beyond the simple color-blind
example might include color-aware mode, configurations where
EIR is greater than CIR, etc.
Reporting Format:
The policer individual report MUST contain all results for each
CIR/EIR/CBS/EBS test run. A recommended format is as follows:
***********************************************************
Test Configuration Summary: Tr, Td
DUT Configuration Summary: CIR, EIR, CBS, EBS
The results table should contain entries for each test run,
as follows (Test #1 to Test #Tr):
- Compliant Traffic Test: BSA, LP, OOS, PD, and PDV
- Excess Traffic Test: BSA
***********************************************************
6.1.2. Policer Capacity Tests
Objective:
The intent of the capacity tests is to verify the policer
performance in a scaled environment with multiple ingress customer
policers on multiple physical ports. This test will benchmark the
maximum number of active policers as specified by the device
manufacturer.
Test Summary:
The specified policing function capacity is generally expressed in
terms of the number of policers active on each individual physical
port as well as the number of unique policer rates that are
utilized. For all of the capacity tests, the benchmarking test
procedure and reporting format described in Section 6.1.1 for a
single policer MUST be applied to each of the physical-port
policers.
For example, a Layer 2 switching device may specify that each of
the 32 physical ports can be policed using a pool of policing
service policies. The device may carry a single customer's
traffic on each physical port, and a single policer is
instantiated per physical port. Another possibility is that a
single physical port may carry multiple customers, in which case
many customer flows would be policed concurrently on an individual
physical port (separate policers per customer on an individual
port).
Test Metrics:
The metrics defined in Section 4.1 (BSA, LP, OOS, PD, and PDV)
SHALL be measured at the egress port and recorded.
The following sections provide the specific test scenarios,
procedures, and reporting formats for each policer capacity test.
6.1.2.1. Maximum Policers on Single Physical Port
Test Summary:
The first policer capacity test will benchmark a single physical
port, with maximum policers on that physical port.
Assume multiple categories of ingress policers at rates
r1, r2, ..., rn. There are multiple customers on a single
physical port. Each customer could be represented by a
single-tagged VLAN, a double-tagged VLAN, a Virtual Private LAN
Service (VPLS) instance, etc. Each customer is mapped to a
different policer. Each of the policers can be of rates
r1, r2, ..., rn.
An example configuration would be
- Y1 customers, policer rate r1
- Y2 customers, policer rate r2
- Y3 customers, policer rate r3
...
- Yn customers, policer rate rn
Some bandwidth on the physical port is dedicated for other traffic
(i.e., other than customer traffic); this includes network control
protocol traffic. There is a separate policer for the other
traffic. Typical deployments have three categories of policers;
there may be some deployments with more or less than three
categories of ingress policers.
Procedure:
1. Configure the DUT policing parameters for the desired CIR/EIR
and CBS/EBS values for each policer rate (r1-rn) to be tested.
2. Configure the tester to generate a stateless traffic burst
equal to CBS and an interval equal to Ti (CBS in bits/CIR) for
each customer stream (Y1-Yn). The encapsulation for each
customer must also be configured according to the service
tested (VLAN, VPLS, IP mapping, etc.).
3. Compliant Traffic Test: Generate bursts of CBS + EBS traffic
into the policer ingress port for each customer traffic stream,
and measure the metrics defined in Section 4.1 (BSA, LP, OOS,
PD, and PDV) at the egress port for each stream and across the
entire Td (default 30-second duration).
4. Excess Traffic Test: Generate bursts of greater than CBS + EBS
bytes into the policer ingress port for each customer traffic
stream, and verify that the policer only allowed the BSA bytes
to exit the egress for each stream. The excess burst MUST be
recorded; the recommended value is 1000 bytes.
Reporting Format:
The policer individual report MUST contain all results for each
CIR/EIR/CBS/EBS test run, per customer traffic stream. A
recommended format is as follows:
*****************************************************************
Test Configuration Summary: Tr, Td
Customer Traffic Stream Encapsulation: Map each stream to VLAN,
VPLS, IP address
DUT Configuration Summary per Customer Traffic Stream: CIR, EIR,
CBS, EBS
The results table should contain entries for each test run,
as follows (Test #1 to Test #Tr):
- Customer Stream Y1-Yn (see note) Compliant Traffic Test:
BSA, LP, OOS, PD, and PDV
- Customer Stream Y1-Yn (see note) Excess Traffic Test: BSA
*****************************************************************
Note: For each test run, there will be two (2) rows for each
customer stream: the Compliant Traffic Test result and the Excess
Traffic Test result.
6.1.2.2. Single Policer on All Physical Ports
Test Summary:
The second policer capacity test involves a single policer
function per physical port with all physical ports active. In
this test, there is a single policer per physical port. The
policer can have one of the rates r1, r2, ..., rn. All of the
physical ports in the networking device are active.
Procedure:
The procedure for this test is identical to the procedure listed
in Section 6.1.1. The configured parameters must be reported
per port, and the test report must include results per measured
egress port.
6.1.2.3. Maximum Policers on All Physical Ports
The third policer capacity test is a combination of the first and
second capacity tests, i.e., maximum policers active per physical
port and all physical ports active.
Procedure:
The procedure for this test is identical to the procedure listed
in Section 6.1.2.1. The configured parameters must be reported
per port, and the test report must include per-stream results per
measured egress port.
6.2. Queue/Scheduler Tests
Queues and traffic scheduling are closely related in that a queue's
priority dictates the manner in which the traffic scheduler transmits
packets out of the egress port.
Since device queues/buffers are generally an egress function, this
test framework will discuss testing at the egress (although the
technique can be applied to ingress-side queues).
Similar to the policing tests, these tests are divided into two
sections: individual queue/scheduler function tests and then
full-capacity tests.
6.2.1. Queue/Scheduler Individual Tests
The various types of scheduling techniques include FIFO, Strict
Priority (SP) queuing, and Weighted Fair Queuing (WFQ), along with
other variations. This test framework recommends testing with a
minimum of three techniques, although benchmarking other
device-scheduling algorithms is left to the discretion of the tester.
6.2.1.1. Testing Queue/Scheduler with Stateless Traffic
Objective:
Verify that the configured queue and scheduling technique can
handle stateless traffic bursts up to the queue depth.
Test Summary:
A network device queue is memory based, unlike a policing
function, which is token or credit based. However, the same
concepts from Section 6.1 can be applied to testing network device
queues.
The device's network queue should be configured to the desired
size in KB (i.e., Queue Length (QL)), and then stateless traffic
should be transmitted to test this QL.
A queue should be able to handle repetitive bursts with the
transmission gaps proportional to the Bottleneck Bandwidth (BB).
The transmission gap is referred to here as the transmission
interval (Ti). The Ti can be defined for the traffic bursts and
is based on the QL and BB of the egress interface.
Ti = QL * 8 / BB
Note that this equation is similar to the Ti required for
transmission into a policer (QL = CBS, BB = CIR). Note also that
the burst hunt algorithm defined in Section 5.1.1 can also be used
to automate the measurement of the queue value.
The stateless traffic burst SHALL be transmitted at the link speed
and spaced within the transmission interval (Ti). The metrics
defined in Section 4.1 SHALL be measured at the egress port and
recorded; the primary intent is to verify the BSA and verify that
no packets are dropped.
The scheduling function must also be characterized to benchmark
the device's ability to schedule the queues according to the
priority. An example would be two levels of priority that include
SP and FIFO queuing. Under a flow load greater than the egress
port speed, the higher-priority packets should be transmitted
without drops (and also maintain low latency), while the lower-
priority (or best-effort) queue may be dropped.
Test Metrics:
The metrics defined in Section 4.1 (BSA, LP, OOS, PD, and PDV)
SHALL be measured at the egress port and recorded.
Procedure:
1. Configure the DUT QL and scheduling technique parameters (FIFO,
SP, etc.).
2. Configure the tester to generate a stateless traffic burst
equal to QL and an interval equal to Ti (QL in bits/BB).
3. Generate bursts of QL traffic into the DUT, and measure the
metrics defined in Section 4.1 (LP, OOS, PD, and PDV) at the
egress port and across the entire Td (default 30-second
duration).
Reporting Format:
The Queue/Scheduler Stateless Traffic individual report MUST
contain all results for each QL/BB test run. A recommended format
is as follows:
****************************************************************
Test Configuration Summary: Tr, Td
DUT Configuration Summary: Scheduling technique (i.e., FIFO, SP,
WFQ, etc.), BB, and QL
The results table should contain entries for each test run,
as follows (Test #1 to Test #Tr):
- LP, OOS, PD, and PDV
****************************************************************
6.2.1.2. Testing Queue/Scheduler with Stateful Traffic
Objective:
Verify that the configured queue and scheduling technique can
handle stateful traffic bursts up to the queue depth.
Test Background and Summary:
To provide a more realistic benchmark and to test queues in
Layer 4 devices such as firewalls, stateful traffic testing is
recommended for the queue tests. Stateful traffic tests will also
utilize the Network Delay Emulator (NDE) from the network setup
configuration in Section 1.2.
The BDP of the TCP test traffic must be calibrated to the QL of
the device queue. Referencing [RFC6349], the BDP is equal to:
BB * RTT / 8 (in bytes)
The NDE must be configured to an RTT value that is large enough to
allow the BDP to be greater than QL. An example test scenario is
defined below:
- Ingress link = GigE
- Egress link = 100 Mbps (BB)
- QL = 32 KB
RTT(min) = QL * 8 / BB and would equal 2.56 ms
(and the BDP = 32 KB)
In this example, one (1) TCP connection with window size / SSB of
32 KB would be required to test the QL of 32 KB. This Bulk
Transfer Test can be accomplished using iperf, as described in
Appendix A.
Two types of TCP tests MUST be performed: the Bulk Transfer Test
and the Micro Burst Test Pattern, as documented in Appendix B.
The Bulk Transfer Test only bursts during the TCP Slow Start (or
Congestion Avoidance) state, while the Micro Burst Test Pattern
emulates application-layer bursting, which may occur any time
during the TCP connection.
Other types of tests SHOULD include the following: simple web
sites, complex web sites, business applications, email, and
SMB/CIFS (Common Internet File System) file copy (all of which are
also documented in Appendix B).
Test Metrics:
The test results will be recorded per the stateful metrics defined
in Section 4.2 -- primarily the TCP Test Pattern Execution Time
(TTPET), TCP Efficiency, and Buffer Delay.
Procedure:
1. Configure the DUT QL and scheduling technique parameters (FIFO,
SP, etc.).
2. Configure the test generator* with a profile of an emulated
application traffic mixture.
- The application mixture MUST be defined in terms of
percentage of the total bandwidth to be tested.
- The rate of transmission for each application within the
mixture MUST also be configurable.
* To ensure repeatable results, the test generator MUST be
capable of generating precise TCP test patterns for each
application specified.
3. Generate application traffic between the ingress (client side)
and egress (server side) ports of the DUT, and measure the
metrics (TTPET, TCP Efficiency, and Buffer Delay) per
application stream and at the ingress and egress ports (across
the entire Td, default 60-second duration).
A couple of items require clarification concerning application
measurements: an application session may be comprised of a single
TCP connection or multiple TCP connections.
If an application session utilizes a single TCP connection, the
application throughput/metrics have a 1-1 relationship to the TCP
connection measurements.
If an application session (e.g., an HTTP-based application)
utilizes multiple TCP connections, then all of the TCP connections
are aggregated in the application throughput measurement/metrics
for that application.
Then, there is the case of multiple instances of an application
session (i.e., multiple FTPs emulating multiple clients). In this
situation, the test should measure/record each FTP application
session independently, tabulating the minimum, maximum, and
average for all FTP sessions.
Finally, application throughput measurements are based on Layer 4
TCP throughput and do not include bytes retransmitted. The TCP
Efficiency metric MUST be measured during the test, because it
provides a measure of "goodput" during each test.
Reporting Format:
The Queue/Scheduler Stateful Traffic individual report MUST
contain all results for each traffic scheduler and QL/BB test run.
A recommended format is as follows:
******************************************************************
Test Configuration Summary: Tr, Td
DUT Configuration Summary: Scheduling technique (i.e., FIFO, SP,
WFQ, etc.), BB, and QL
Application Mixture and Intensities: These are the percentages
configured for each application type.
The results table should contain entries for each test run, with
minimum, maximum, and average per application session, as follows
(Test #1 to Test #Tr):
- Throughput (bps) and TTPET for each application session
- Bytes In and Bytes Out for each application session
- TCP Efficiency and Buffer Delay for each application session
******************************************************************
6.2.2. Queue/Scheduler Capacity Tests
Objective:
The intent of these capacity tests is to benchmark queue/scheduler
performance in a scaled environment with multiple
queues/schedulers active on multiple egress physical ports. These
tests will benchmark the maximum number of queues and schedulers
as specified by the device manufacturer. Each priority in the
system will map to a separate queue.
Test Metrics:
The metrics defined in Section 4.1 (BSA, LP, OOS, PD, and PDV)
SHALL be measured at the egress port and recorded.
The following sections provide the specific test scenarios,
procedures, and reporting formats for each queue/scheduler capacity
test.
6.2.2.1. Multiple Queues, Single Port Active
For the first queue/scheduler capacity test, multiple queues per port
will be tested on a single physical port. In this case, all of the
queues (typically eight) are active on a single physical port.
Traffic from multiple ingress physical ports is directed to the same
egress physical port. This will cause oversubscription on the egress
physical port.
There are many types of priority schemes and combinations of
priorities that are managed by the scheduler. The following sections
specify the priority schemes that should be tested.
6.2.2.1.1. Strict Priority on Egress Port
Test Summary:
For this test, SP scheduling on the egress physical port should be
tested, and the benchmarking methodologies specified in
Sections 6.2.1.1 (stateless) and 6.2.1.2 (stateful) (procedure,
metrics, and reporting format) should be applied here. For a
given priority, each ingress physical port should get a fair share
of the egress physical-port bandwidth.
Since this is a capacity test, the configuration and report
results format (see Sections 6.2.1.1 and 6.2.1.2) MUST also
include:
Configuration:
- The number of physical ingress ports active during the test
- The classification marking (DSCP, VLAN, etc.) for each physical
ingress port
- The traffic rate for stateful traffic and the traffic
rate/mixture for stateful traffic for each physical
ingress port
Report Results:
- For each ingress port traffic stream, the achieved throughput
rate and metrics at the egress port
6.2.2.1.2. Strict Priority + WFQ on Egress Port
Test Summary:
For this test, SP and WFQ should be enabled simultaneously in the
scheduler, but on a single egress port. The benchmarking
methodologies specified in Sections 6.2.1.1 (stateless) and
6.2.1.2 (stateful) (procedure, metrics, and reporting format)
should be applied here. Additionally, the egress port
bandwidth-sharing among weighted queues should be proportional to
the assigned weights. For a given priority, each ingress physical
port should get a fair share of the egress physical-port
bandwidth.
Since this is a capacity test, the configuration and report
results format (see Sections 6.2.1.1 and 6.2.1.2) MUST also
include:
Configuration:
- The number of physical ingress ports active during the test
- The classification marking (DSCP, VLAN, etc.) for each physical
ingress port
- The traffic rate for stateful traffic and the traffic
rate/mixture for stateful traffic for each physical
ingress port
Report Results:
- For each ingress port traffic stream, the achieved throughput
rate and metrics at each queue of the egress port queue (both
the SP and WFQ)
Example:
- Egress Port SP Queue: throughput and metrics for ingress
streams 1-n
- Egress Port WFQ: throughput and metrics for ingress streams 1-n
6.2.2.2. Single Queue per Port, All Ports Active
Test Summary:
Traffic from multiple ingress physical ports is directed to the
same egress physical port. This will cause oversubscription on
the egress physical port. Also, the same amount of traffic is
directed to each egress physical port.
The benchmarking methodologies specified in Sections 6.2.1.1
(stateless) and 6.2.1.2 (stateful) (procedure, metrics, and
reporting format) should be applied here. Each ingress physical
port should get a fair share of the egress physical-port
bandwidth. Additionally, each egress physical port should receive
the same amount of traffic.
Since this is a capacity test, the configuration and report
results format (see Sections 6.2.1.1 and 6.2.1.2) MUST also
include:
Configuration:
- The number of ingress ports active during the test
- The number of egress ports active during the test
- The classification marking (DSCP, VLAN, etc.) for each physical
ingress port
- The traffic rate for stateful traffic and the traffic
rate/mixture for stateful traffic for each physical
ingress port
Report Results:
- For each egress port, the achieved throughput rate and metrics
at the egress port queue for each ingress port stream
Example:
- Egress Port 1: throughput and metrics for ingress streams 1-n
- Egress Port n: throughput and metrics for ingress streams 1-n
6.2.2.3. Multiple Queues per Port, All Ports Active
Test Summary:
Traffic from multiple ingress physical ports is directed to all
queues of each egress physical port. This will cause
oversubscription on the egress physical ports. Also, the same
amount of traffic is directed to each egress physical port.
The benchmarking methodologies specified in Sections 6.2.1.1
(stateless) and 6.2.1.2 (stateful) (procedure, metrics, and
reporting format) should be applied here. For a given priority,
each ingress physical port should get a fair share of the egress
physical-port bandwidth. Additionally, each egress physical port
should receive the same amount of traffic.
Since this is a capacity test, the configuration and report
results format (see Sections 6.2.1.1 and 6.2.1.2) MUST also
include:
Configuration:
- The number of physical ingress ports active during the test
- The classification marking (DSCP, VLAN, etc.) for each physical
ingress port
- The traffic rate for stateful traffic and the traffic
rate/mixture for stateful traffic for each physical
ingress port
Report Results:
- For each egress port, the achieved throughput rate and metrics
at each egress port queue for each ingress port stream
Example:
- Egress Port 1, SP Queue: throughput and metrics for ingress
streams 1-n
- Egress Port 2, WFQ: throughput and metrics for ingress
streams 1-n
...
- Egress Port n, SP Queue: throughput and metrics for ingress
streams 1-n
- Egress Port n, WFQ: throughput and metrics for ingress
streams 1-n
6.3. Shaper Tests
Like a queue, a traffic shaper is memory based, but with the added
intelligence of an active traffic scheduler. The same concepts as
those described in Section 6.2 (queue testing) can be applied to
testing a network device shaper.
Again, the tests are divided into two sections: individual shaper
benchmark tests and then full-capacity shaper benchmark tests.
6.3.1. Shaper Individual Tests
A traffic shaper generally has three (3) components that can be
configured:
- Ingress Queue bytes
- Shaper Rate (SR), bps
- Burst Committed (Bc) and Burst Excess (Be), bytes
The Ingress Queue holds burst traffic, and the shaper then meters
traffic out of the egress port according to the SR and Bc/Be
parameters. Shapers generally transmit into policers, so the idea is
for the emitted traffic to conform to the policer's limits.
6.3.1.1. Testing Shaper with Stateless Traffic
Objective:
Test a shaper by transmitting stateless traffic bursts into the
shaper ingress port and verifying that the egress traffic is
shaped according to the shaper traffic profile.
Test Summary:
The stateless traffic must be burst into the DUT ingress port and
not exceed the Ingress Queue. The burst can be a single burst or
multiple bursts. If multiple bursts are transmitted, then the
transmission interval (Ti) must be large enough so that the SR is
not exceeded. An example will clarify single-burst and multiple-
burst test cases.
In this example, the shaper's ingress and egress ports are both
full-duplex Gigabit Ethernet. The Ingress Queue is configured to
be 512,000 bytes, the SR = 50 Mbps, and both Bc and Be are
configured to be 32,000 bytes. For a single-burst test, the
transmitting test device would burst 512,000 bytes maximum into
the ingress port and then stop transmitting.
If a multiple-burst test is to be conducted, then the burst bytes
divided by the transmission interval between the 512,000-byte
bursts must not exceed the SR. The transmission interval (Ti)
must adhere to a formula similar to the formula described in
Section 6.2.1.1 for queues, namely:
Ti = Ingress Queue * 8 / SR
For the example from the previous paragraph, the Ti between bursts
must be greater than 82 milliseconds (512,000 bytes * 8 /
50,000,000 bps). This yields an average rate of 50 Mbps so that
an Ingress Queue would not overflow.
Test Metrics:
The metrics defined in Section 4.1 (LP, OOS, PDV, SR, SBB, and
SBI) SHALL be measured at the egress port and recorded.
Procedure:
1. Configure the DUT shaper ingress QL and shaper egress rate
parameters (SR, Bc, Be).
2. Configure the tester to generate a stateless traffic burst
equal to QL and an interval equal to Ti (QL in bits/BB).
3. Generate bursts of QL traffic into the DUT, and measure the
metrics defined in Section 4.1 (LP, OOS, PDV, SR, SBB, and SBI)
at the egress port and across the entire Td (default 30-second
duration).
Reporting Format:
The Shaper Stateless Traffic individual report MUST contain all
results for each QL/SR test run. A recommended format is as
follows:
***********************************************************
Test Configuration Summary: Tr, Td
DUT Configuration Summary: Ingress Burst Rate, QL, SR
The results table should contain entries for each test run,
as follows (Test #1 to Test #Tr):
- LP, OOS, PDV, SR, SBB, and SBI
***********************************************************
6.3.1.2. Testing Shaper with Stateful Traffic
Objective:
Test a shaper by transmitting stateful traffic bursts into the
shaper ingress port and verifying that the egress traffic is
shaped according to the shaper traffic profile.
Test Summary:
To provide a more realistic benchmark and to test queues in
Layer 4 devices such as firewalls, stateful traffic testing is
also recommended for the shaper tests. Stateful traffic tests
will also utilize the Network Delay Emulator (NDE) from the
network setup configuration in Section 1.2.
The BDP of the TCP test traffic must be calculated as described in
Section 6.2.1.2. To properly stress network buffers and the
traffic-shaping function, the TCP window size (which is the
minimum of the TCP RWND and sender socket) should be greater than
the BDP, which will stress the shaper. BDP factors of 1.1 to 1.5
are recommended, but the values are left to the discretion of the
tester and should be documented.
The cumulative TCP window sizes* (RWND at the receiving end and
CWND at the transmitting end) equates to the TCP window size* for
each connection, multiplied by the number of connections.
* As described in Section 3 of [RFC6349], the SSB MUST be large
enough to fill the BDP.
For example, if the BDP is equal to 256 KB and a connection size
of 64 KB is used for each connection, then it would require four
(4) connections to fill the BDP and 5-6 connections (oversubscribe
the BDP) to stress-test the traffic-shaping function.
Two types of TCP tests MUST be performed: the Bulk Transfer Test
and the Micro Burst Test Pattern, as documented in Appendix B.
The Bulk Transfer Test only bursts during the TCP Slow Start (or
Congestion Avoidance) state, while the Micro Burst Test Pattern
emulates application-layer bursting, which may occur any time
during the TCP connection.
Other types of tests SHOULD include the following: simple web
sites, complex web sites, business applications, email, and
SMB/CIFS file copy (all of which are also documented in
Appendix B).
Test Metrics:
The test results will be recorded per the stateful metrics defined
in Section 4.2 -- primarily the TCP Test Pattern Execution Time
(TTPET), TCP Efficiency, and Buffer Delay.
Procedure:
1. Configure the DUT shaper ingress QL and shaper egress rate
parameters (SR, Bc, Be).
2. Configure the test generator* with a profile of an emulated
application traffic mixture.
- The application mixture MUST be defined in terms of
percentage of the total bandwidth to be tested.
- The rate of transmission for each application within the
mixture MUST also be configurable.
* To ensure repeatable results, the test generator MUST be
capable of generating precise TCP test patterns for each
application specified.
3. Generate application traffic between the ingress (client side)
and egress (server side) ports of the DUT, and measure the
metrics (TTPET, TCP Efficiency, and Buffer Delay) per
application stream and at the ingress and egress ports (across
the entire Td, default 30-second duration).
Reporting Format:
The Shaper Stateful Traffic individual report MUST contain all
results for each traffic scheduler and QL/SR test run. A
recommended format is as follows:
******************************************************************
Test Configuration Summary: Tr, Td
DUT Configuration Summary: Ingress Burst Rate, QL, SR
Application Mixture and Intensities: These are the percentages
configured for each application type.
The results table should contain entries for each test run, with
minimum, maximum, and average per application session, as follows
(Test #1 to Test #Tr):
- Throughput (bps) and TTPET for each application session
- Bytes In and Bytes Out for each application session
- TCP Efficiency and Buffer Delay for each application session
******************************************************************
6.3.2. Shaper Capacity Tests
Objective:
The intent of these scalability tests is to verify shaper
performance in a scaled environment with shapers active on
multiple queues on multiple egress physical ports. These tests
will benchmark the maximum number of shapers as specified by the
device manufacturer.
The following sections provide the specific test scenarios,
procedures, and reporting formats for each shaper capacity test.
6.3.2.1. Single Queue Shaped, All Physical Ports Active
Test Summary:
The first shaper capacity test involves per-port shaping with all
physical ports active. Traffic from multiple ingress physical
ports is directed to the same egress physical port. This will
cause oversubscription on the egress physical port. Also, the
same amount of traffic is directed to each egress physical port.
The benchmarking methodologies specified in Sections 6.3.1.1
(stateless) and 6.3.1.2 (stateful) (procedure, metrics, and
reporting format) should be applied here. Since this is a
capacity test, the configuration and report results format (see
Section 6.3.1) MUST also include:
Configuration:
- The number of physical ingress ports active during the test
- The classification marking (DSCP, VLAN, etc.) for each physical
ingress port
- The traffic rate for stateful traffic and the traffic
rate/mixture for stateful traffic for each physical
ingress port
- The shaped egress port shaper parameters (QL, SR, Bc, Be)
Report Results:
- For each active egress port, the achieved throughput rate and
shaper metrics for each ingress port traffic stream
Example:
- Egress Port 1: throughput and metrics for ingress streams 1-n
- Egress Port n: throughput and metrics for ingress streams 1-n
6.3.2.2. All Queues Shaped, Single Port Active
Test Summary:
The second shaper capacity test is conducted with all queues
actively shaping on a single physical port. The benchmarking
methodology described in the per-port shaping test
(Section 6.3.2.1) serves as the foundation for this.
Additionally, each of the SP queues on the egress physical port is
configured with a shaper. For the highest-priority queue, the
maximum amount of bandwidth available is limited by the bandwidth
of the shaper. For the lower-priority queues, the maximum amount
of bandwidth available is limited by the bandwidth of the shaper
and traffic in higher-priority queues.
The benchmarking methodologies specified in Sections 6.3.1.1
(stateless) and 6.3.1.2 (stateful) (procedure, metrics, and
reporting format) should be applied here. Since this is a
capacity test, the configuration and report results format (see
Section 6.3.1) MUST also include:
Configuration:
- The number of physical ingress ports active during the test
- The classification marking (DSCP, VLAN, etc.) for each physical
ingress port
- The traffic rate for stateful traffic and the traffic
rate/mixture for stateful traffic for each physical
ingress port
- For the active egress port, each of the following shaper queue
parameters: QL, SR, Bc, Be
Report Results:
- For each queue of the active egress port, the achieved
throughput rate and shaper metrics for each ingress port
traffic stream
Example:
- Egress Port High-Priority Queue: throughput and metrics for
ingress streams 1-n
- Egress Port Lower-Priority Queue: throughput and metrics for
ingress streams 1-n
6.3.2.3. All Queues Shaped, All Ports Active
Test Summary:
For the third shaper capacity test (which is a combination of the
tests listed in Sections 6.3.2.1 and 6.3.2.2), all queues will be
actively shaping and all physical ports active.
The benchmarking methodologies specified in Sections 6.3.1.1
(stateless) and 6.3.1.2 (stateful) (procedure, metrics, and
reporting format) should be applied here. Since this is a
capacity test, the configuration and report results format (see
Section 6.3.1) MUST also include:
Configuration:
- The number of physical ingress ports active during the test
- The classification marking (DSCP, VLAN, etc.) for each physical
ingress port
- The traffic rate for stateful traffic and the traffic
rate/mixture for stateful traffic for each physical
ingress port
- For each of the active egress ports: shaper port parameters and
per-queue parameters (QL, SR, Bc, Be)
Report Results:
- For each queue of each active egress port, the achieved
throughput rate and shaper metrics for each ingress port
traffic stream
Example:
- Egress Port 1, High-Priority Queue: throughput and metrics for
ingress streams 1-n
- Egress Port 1, Lower-Priority Queue: throughput and metrics for
ingress streams 1-n
...
- Egress Port n, High-Priority Queue: throughput and metrics for
ingress streams 1-n
- Egress Port n, Lower-Priority Queue: throughput and metrics for
ingress streams 1-n
6.4. Concurrent Capacity Load Tests
As mentioned in Section 3 of this document, it is impossible to
specify the various permutations of concurrent traffic management
functions that should be tested in a device for capacity testing.
However, some profiles are listed below that may be useful for
testing multiple configurations of traffic management functions:
- Policers on ingress and queuing on egress
- Policers on ingress and shapers on egress (not intended for a flow
to be policed and then shaped; these would be two different flows
tested at the same time)
The test procedures and reporting formats from Sections 6.1, 6.2,
and 6.3 may be modified to accommodate the capacity test profile.
7. Security Considerations
Documents of this type do not directly affect the security of the
Internet or of corporate networks as long as benchmarking is not
performed on devices or systems connected to production networks.
Further, benchmarking is performed on a "black box" basis, relying
solely on measurements observable external to the DUT/SUT.
Special capabilities SHOULD NOT exist in the DUT/SUT specifically for
benchmarking purposes. Any implications for network security arising
from the DUT/SUT SHOULD be identical in the lab and in production
networks.
8. References
8.1. Normative References
[3GPP2-C_R1002-A]
3rd Generation Partnership Project 2, "cdma2000 Evaluation
Methodology", Version 1.0, Revision A, May 2009,
<http://www.3gpp2.org/public_html/specs/
C.R1002-A_v1.0_Evaluation_Methodology.pdf>.
[RFC1242] Bradner, S., "Benchmarking Terminology for Network
Interconnection Devices", RFC 1242, DOI 10.17487/RFC1242,
July 1991, <http://www.rfc-editor.org/info/rfc1242>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544,
DOI 10.17487/RFC2544, March 1999,
<http://www.rfc-editor.org/info/rfc2544>.
[RFC2680] Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way
Packet Loss Metric for IPPM", RFC 2680,
DOI 10.17487/RFC2680, September 1999,
<http://www.rfc-editor.org/info/rfc2680>.
[RFC3148] Mathis, M. and M. Allman, "A Framework for Defining
Empirical Bulk Transfer Capacity Metrics", RFC 3148,
DOI 10.17487/RFC3148, July 2001,
<http://www.rfc-editor.org/info/rfc3148>.
[RFC4115] Aboul-Magd, O. and S. Rabie, "A Differentiated Service
Two-Rate, Three-Color Marker with Efficient Handling of
in-Profile Traffic", RFC 4115, DOI 10.17487/RFC4115,
July 2005, <http://www.rfc-editor.org/info/rfc4115>.
[RFC4689] Poretsky, S., Perser, J., Erramilli, S., and S. Khurana,
"Terminology for Benchmarking Network-layer Traffic
Control Mechanisms", RFC 4689, DOI 10.17487/RFC4689,
October 2006, <http://www.rfc-editor.org/info/rfc4689>.
[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
S., and J. Perser, "Packet Reordering Metrics", RFC 4737,
DOI 10.17487/RFC4737, November 2006,
<http://www.rfc-editor.org/info/rfc4737>.
[RFC5481] Morton, A. and B. Claise, "Packet Delay Variation
Applicability Statement", RFC 5481, DOI 10.17487/RFC5481,
March 2009, <http://www.rfc-editor.org/info/rfc5481>.
[RFC6349] Constantine, B., Forget, G., Geib, R., and R. Schrage,
"Framework for TCP Throughput Testing", RFC 6349,
DOI 10.17487/RFC6349, August 2011,
<http://www.rfc-editor.org/info/rfc6349>.
[RFC6703] Morton, A., Ramachandran, G., and G. Maguluri, "Reporting
IP Network Performance Metrics: Different Points of View",
RFC 6703, DOI 10.17487/RFC6703, August 2012,
<http://www.rfc-editor.org/info/rfc6703>.
[SPECweb2009]
Standard Performance Evaluation Corporation (SPEC),
"SPECweb2009 Release 1.20 Benchmark Design Document",
April 2010, <https://www.spec.org/web2009/docs/design/
SPECweb2009_Design.html>.
8.2. Informative References
[CA-Benchmark]
Hamilton, M. and S. Banks, "Benchmarking Methodology for
Content-Aware Network Devices", Work in Progress,
draft-ietf-bmwg-ca-bench-meth-04, February 2013.
[CoDel] Nichols, K., Jacobson, V., McGregor, A., and J. Iyengar,
"Controlled Delay Active Queue Management", Work in
Progress, draft-ietf-aqm-codel-01, April 2015.
[MEF-10.2]
[MEF-10.3] Metro Ethernet Forum, "Ethernet Services Attributes
Phase 2", 3", MEF 10.2, 10.3, October 2009, 2013,
<https://www.mef.net/Assets/Technical_Specifications/
PDF/MEF_10.2.pdf>.
[MEF-12.1]
PDF/MEF_10.3.pdf>.
[MEF-12.2] Metro Ethernet Forum, "Carrier Ethernet Network
Architecture Framework -- Part 2: Ethernet Services Layer
- Base Elements",
Layer", MEF 12.1, April 2010, 12.2, May 2014,
<https://www.mef.net/Assets/Technical_Specifications/
PDF/MEF_12.1.pdf>.
PDF/MEF_12.2.pdf>.
[MEF-14] Metro Ethernet Forum, "Abstract Test Suite for Traffic
Management Phase 1", MEF 14, November 2005,
<https://www.mef.net/Assets/
Technical_Specifications/PDF/MEF_14.pdf>.
[MEF-19] Metro Ethernet Forum, "Abstract Test Suite for UNI
Type 1", MEF 19, April 2007, <https://www.mef.net/Assets/
Technical_Specifications/PDF/MEF_19.pdf>.
[MEF-26]
[MEF-26.1] Metro Ethernet Forum, "External Network Network Interface
(ENNI) - Phase 1", 2", MEF 26, 26.1, January 2010, 2012,
<http://www.mef.net/Assets/Technical_Specifications/
PDF/MEF_26.pdf>.
PDF/MEF_26.1.pdf>.
[MEF-37] Metro Ethernet Forum, "Abstract Test Suite for ENNI",
MEF 37, January 2012, <https://www.mef.net/Assets/
Technical_Specifications/PDF/MEF_37.pdf>.
[PIE] Pan, R., Natarajan, P., Baker, F., White, G., VerSteeg,
B., Prabhu, M., Piglione, C., and V. Subramanian, "PIE: A
Lightweight Control Scheme To Address the Bufferbloat
Problem", Work in Progress, draft-ietf-aqm-pie-02,
August 2015.
[RFC2697] Heinanen, J. and R. Guerin, "A Single Rate Three Color
Marker", RFC 2697, DOI 10.17487/RFC2697, September 1999,
<http://www.rfc-editor.org/info/rfc2697>.
[RFC2698] Heinanen, J. and R. Guerin, "A Two Rate Three Color
Marker", RFC 2698, DOI 10.17487/RFC2698, September 1999,
<http://www.rfc-editor.org/info/rfc2698>.
[RFC7567] Baker, F., Ed., and G. Fairhurst, Ed., "IETF
Recommendations Regarding Active Queue Management",
BCP 197, RFC 7567, DOI 10.17487/RFC7567, July 2015,
<http://www.rfc-editor.org/info/rfc7567>.
Appendix A. Open Source Tools for Traffic Management Testing
This framework specifies that stateless and stateful behaviors SHOULD
both be tested. Some open source tools that can be used to
accomplish many of the tests proposed in this framework are iperf,
netperf (with netperf-wrapper), the "uperf" tool, Tmix,
TCP-incast-generator, and D-ITG (Distributed Internet Traffic
Generator).
iperf can generate UDP-based or TCP-based traffic; a client and
server must both run the iperf software in the same traffic mode.
The server is set up to listen, and then the test traffic is
controlled from the client. Both unidirectional and bidirectional
concurrent testing are supported.
The UDP mode can be used for the stateless traffic testing. The
target bandwidth, packet size, UDP port, and test duration can be
controlled. A report of bytes transmitted, packets lost, and delay
variation is provided by the iperf receiver.
iperf (TCP mode), TCP-incast-generator, and D-ITG can be used for
stateful traffic testing to test bulk transfer traffic. The TCP
window size (which is actually the SSB), number of connections,
packet size, TCP port, and test duration can be controlled. A report
of bytes transmitted and throughput achieved is provided by the iperf
sender, while TCP-incast-generator and D-ITG provide even more
statistics.
netperf is a software application that provides network bandwidth
testing between two hosts on a network. It supports UNIX domain
sockets, TCP, SCTP, and UDP via BSD Sockets. netperf provides a
number of predefined tests, e.g., to measure bulk (unidirectional)
data transfer or request/response performance
(http://en.wikipedia.org/wiki/Netperf). netperf-wrapper is a Python
script that runs multiple simultaneous netperf instances and
aggregates the results.
uperf uses a description (or model) of an application mixture. It
generates the load according to the model descriptor. uperf is more
flexible than netperf in its ability to generate request/response
application behavior within a single TCP connection. The application
model descriptor can be based on empirical data, but at the time of
this writing, the import of packet captures is not directly
supported.
Tmix is another application traffic emulation tool. It uses packet
captures directly to create the traffic profile. The packet trace is
"reverse compiled" into a source-level characterization, called a
"connection vector", of each TCP connection present in the trace.
While most widely used in ns2 simulation environments, Tmix also runs
on Linux hosts.
The traffic generation capabilities of these open source tools
facilitate the emulation of the TCP test patterns discussed in
Appendix B.
Appendix B. Stateful TCP Test Patterns
This framework recommends at a minimum the following TCP test
patterns, since they are representative of real-world application
traffic (Section 5.2.1 describes some methods to derive other
application-based TCP test patterns).
- Bulk Transfer: Generate concurrent TCP connections whose aggregate
number of in-flight data bytes would fill the BDP. Guidelines
from [RFC6349] are used to create this TCP traffic pattern.
- Micro Burst: Generate precise burst patterns within a single TCP
connection or multiple TCP connections. The idea is for TCP to
establish equilibrium and then burst application bytes at defined
sizes. The test tool must allow the burst size and burst time
interval to be configurable.
- Web Site Patterns: The HTTP traffic model shown in Table 4.1.3-1
of [3GPP2-C_R1002-A] demonstrates a way to develop these TCP test
patterns. In summary, the HTTP traffic model consists of the
following parameters:
- Main object size (Sm)
- Embedded object size (Se)
- Number of embedded objects per page (Nd)
- Client processing time (Tcp)
- Server processing time (Tsp)
Web site test patterns are illustrated with the following examples:
- Simple web site: Mimic the request/response and object download
behavior of a basic web site (small company).
- Complex web site: Mimic the request/response and object download
behavior of a complex web site (eCommerce site).
Referencing the HTTP traffic model parameters, the following table
was derived (by analysis and experimentation) for simple web site and
complex web site TCP test patterns:
Simple Complex
Parameter Web Site Web Site
-----------------------------------------------------
Main object Ave. = 10KB Ave. = 300KB
size (Sm) Min. = 100B Min. = 50KB
Max. = 500KB Max. = 2MB
Embedded object Ave. = 7KB Ave. = 10KB
size (Se) Min. = 50B Min. = 100B
Max. = 350KB Max. = 1MB
Number of embedded Ave. = 5 Ave. = 25
objects per page (Nd) Min. = 2 Min. = 10
Max. = 10 Max. = 50
Client processing Ave. = 3s Ave. = 10s
time (Tcp)* Min. = 1s Min. = 3s
Max. = 10s Max. = 30s
Server processing Ave. = 5s Ave. = 8s
time (Tsp)* Min. = 1s Min. = 2s
Max. = 15s Max. = 30s
* The client and server processing time is distributed across the
transmission/receipt of all of the main and embedded objects.
To be clear, the parameters in this table are reasonable guidelines
for the TCP test pattern traffic generation. The test tool can use
fixed parameters for simpler tests and mathematical distributions for
more complex tests. However, the test pattern must be repeatable to
ensure that the benchmark results can be reliably compared.
- Interactive Patterns: While web site patterns are interactive to a
degree, they mainly emulate the downloading of web sites of
varying complexity. Interactive patterns are more chatty in
nature, since there is a lot of user interaction with the servers.
Examples include business applications such as PeopleSoft and
Oracle, and consumer applications such as Facebook and IM. For
the interactive patterns, the packet capture technique was used to
characterize some business applications and also the email
application.
In summary, an interactive application can be described by the
following parameters:
- Client message size (Scm)
- Number of client messages (Nc)
- Server response size (Srs)
- Number of server messages (Ns)
- Client processing time (Tcp)
- Server processing time (Tsp)
- File size upload (Su)*
- File size download (Sd)*
* The file size parameters account for attachments uploaded or
downloaded and may not be present in all interactive applications.
Again using packet capture as a means to characterize, the following
table reflects the guidelines for simple business applications,
complex business applications, eCommerce, and email Send/Receive:
Simple Complex
Business Business
Parameter Application Application eCommerce* Email
--------------------------------------------------------------------
Client message Ave. = 450B Ave. = 2KB Ave. = 1KB Ave. = 200B
size (Scm) Min. = 100B Min. = 500B Min. = 100B Min. = 100B
Max. = 1.5KB Max. = 100KB Max. = 50KB Max. = 1KB
Number of client Ave. = 10 Ave. = 100 Ave. = 20 Ave. = 10
messages (Nc) Min. = 5 Min. = 50 Min. = 10 Min. = 5
Max. = 25 Max. = 250 Max. = 100 Max. = 25
Client processing Ave. = 10s Ave. = 30s Ave. = 15s Ave. = 5s
time (Tcp)** Min. = 3s Min. = 3s Min. = 5s Min. = 3s
Max. = 30s Max. = 60s Max. = 120s Max. = 45s
Server response Ave. = 2KB Ave. = 5KB Ave. = 8KB Ave. = 200B
size (Srs) Min. = 500B Min. = 1KB Min. = 100B Min. = 150B
Max. = 100KB Max. = 1MB Max. = 50KB Max. = 750B
Number of server Ave. = 50 Ave. = 200 Ave. = 100 Ave. = 15
messages (Ns) Min. = 10 Min. = 25 Min. = 15 Min. = 5
Max. = 200 Max. = 1000 Max. = 500 Max. = 40
Server processing Ave. = 0.5s Ave. = 1s Ave. = 2s Ave. = 4s
time (Tsp)** Min. = 0.1s Min. = 0.5s Min. = 1s Min. = 0.5s
Max. = 5s Max. = 20s Max. = 10s Max. = 15s
File size Ave. = 50KB Ave. = 100KB Ave. = N/A Ave. = 100KB
upload (Su) Min. = 2KB Min. = 10KB Min. = N/A Min. = 20KB
Max. = 200KB Max. = 2MB Max. = N/A Max. = 10MB
File size Ave. = 50KB Ave. = 100KB Ave. = N/A Ave. = 100KB
download (Sd) Min. = 2KB Min. = 10KB Min. = N/A Min. = 20KB
Max. = 200KB Max. = 2MB Max. = N/A Max. = 10MB
* eCommerce used a combination of packet capture techniques and
reference traffic flows as described in [SPECweb2009].
** The client and server processing time is distributed across the
transmission/receipt of all of the messages. The client
processing time consists mainly of the delay between user
interactions (not machine processing).
Again, the parameters in this table are the guidelines for the TCP
test pattern traffic generation. The test tool can use fixed
parameters for simpler tests and mathematical distributions for more
complex tests. However, the test pattern must be repeatable to
ensure that the benchmark results can be reliably compared.
- SMB/CIFS file copy: Mimic a network file copy, both read and
write. As opposed to FTP, which is a bulk transfer and is only
flow-controlled via TCP, SMB/CIFS divides a file into application
blocks and utilizes application-level handshaking in addition to
TCP flow control.
In summary, an SMB/CIFS file copy can be described by the following
parameters:
- Client message size (Scm)
- Number of client messages (Nc)
- Server response size (Srs)
- Number of server messages (Ns)
- Client processing time (Tcp)
- Server processing time (Tsp)
- Block size (Sb)
The client and server messages are SMB control messages. The block
size is the data portion of the file transfer.
Again using packet capture as a means to characterize, the following
table reflects the guidelines for SMB/CIFS file copy:
SMB/CIFS
Parameter File Copy
--------------------------------
Client message Ave. = 450B
size (Scm) Min. = 100B
Max. = 1.5KB
Number of client Ave. = 10
messages (Nc) Min. = 5
Max. = 25
Client processing Ave. = 1ms
time (Tcp) Min. = 0.5ms
Max. = 2
Server response Ave. = 2KB
size (Srs) Min. = 500B
Max. = 100KB
Number of server Ave. = 10
messages (Ns) Min. = 10
Max. = 200
Server processing Ave. = 1ms
time (Tsp) Min. = 0.5ms
Max. = 2ms
Block Ave. = N/A
size (Sb)* Min. = 16KB
Max. = 128KB
* Depending upon the tested file size, the block size will be
transferred "n" number of times to complete the example. An
example would be a 10 MB file test and 64 KB block size. In
this case, 160 blocks would be transferred after the control
channel is opened between the client and server.
Acknowledgments
We would like to thank Al Morton for his continuous review and
invaluable input to this document. We would also like to thank Scott
Bradner for providing guidance early in this document's conception,
in the area of the benchmarking scope of traffic management
functions. Additionally, we would like to thank Tim Copley for his
original input, as well as David Taht, Gory Erg, and Toke
Hoiland-Jorgensen for their review and input for the AQM group.
Also, for the formal reviews of this document, we would like to thank
Gilles Forget, Vijay Gurbani, Reinhard Schrage, and Bhuvaneswaran
Vengainathan.
Authors' Addresses
Barry Constantine
JDSU, Test and Measurement Division
Germantown, MD 20876-7100
United States
Phone: +1-240-404-2227
Email: barry.constantine@jdsu.com
Ram (Ramki) Krishnan
Dell Inc.
Santa Clara, CA 95054
United States
Phone: +1-408-406-7890
Email: ramkri123@gmail.com