Network Working Group B. Constantine Internet Draft JDSU Intended status: Informational R. Krishnan Expires: February 2016 Dell Inc. June 9, 2015 Traffic Management Benchmarking draft-ietf-bmwg-traffic-management-06.txt Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on December 9, 2015. Constantine June 9, 2015 [Page 1] Internet-Draft Traffic Management Benchmarking June, 2015 Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Abstract This framework describes a practical methodology for benchmarking the traffic management capabilities of networking devices (i.e. policing, shaping, etc.). The goal is 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. Constantine June 9, 2015 [Page 2] Internet-Draft Traffic Management Benchmarking June, 2015 Table of Contents 1. Introduction...................................................4 1.1. Traffic Management Overview...............................4 1.2. DUT Lab Configuration and Testing Overview................5 2. Conventions used in this document..............................7 3. Scope and Goals................................................8 4. Traffic Benchmarking Metrics...................................9 4.1. Metrics for Stateless Traffic Tests......................10 4.2. Metrics for Stateful Traffic Tests.......................11 5. Tester Capabilities...........................................12 5.1. Stateless Test Traffic Generation........................13 5.1.1. Burst Hunt with Stateless Traffic...................13 5.2. Stateful Test Pattern Generation.........................13 5.2.1. TCP Test Pattern Definitions........................15 6. Traffic Benchmarking Methodology..............................16 6.1. Policing Tests...........................................16 6.1.1 Policer Individual Tests................................17 6.1.2 Policer Capacity Tests..............................18 6.1.2.1 Maximum Policers on Single Physical Port..........19 6.1.2.2 Single Policer on All Physical Ports..............20 6.1.2.3 Maximum Policers on All Physical Ports............21 6.2. Queue/Scheduler Tests....................................21 6.2.1 Queue/Scheduler Individual Tests........................21 6.2.1.1 Testing Queue/Scheduler with Stateless Traffic....21 6.2.1.2 Testing Queue/Scheduler with Stateful Traffic.....23 6.2.2 Queue / Scheduler Capacity Tests......................25 6.2.2.1 Multiple Queues / Single Port Active..............25 6.2.2.1.1 Strict Priority on Egress Port..................26 6.2.2.1.2 Strict Priority + Weighted Fair Queue (WFQ).....26 6.2.2.2 Single Queue per Port / All Ports Active..........27 6.2.2.3 Multiple Queues per Port, All Ports Active........27 6.3. Shaper tests.............................................28 6.3.1 Shaper Individual Tests...............................28 6.3.1.1 Testing Shaper with Stateless Traffic.............29 6.3.1.2 Testing Shaper with Stateful Traffic..............30 6.3.2 Shaper Capacity Tests.................................32 6.3.2.1 Single Queue Shaped, All Physical Ports Active....32 6.3.2.2 All Queues Shaped, Single Port Active.............32 6.3.2.3 All Queues Shaped, All Ports Active...............33 6.4. Concurrent Capacity Load Tests...........................34 7. Security Considerations.......................................34 8. IANA Considerations...........................................34 9. References....................................................35 9.1. Normative References.....................................35 9.2. Informative References...................................35 Appendix A: Open Source Tools for Traffic Management Testing.....36 Appendix B: Stateful TCP Test Patterns...........................37 Acknowledgments..................................................41 Authors' Addresses...............................................42 Constantine June 9, 2015 [Page 3] Internet-Draft Traffic Management Benchmarking June, 2015 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 which are described in Section 1.1. This draft 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 draft 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), Differential Services Code Point (DSCP) etc.) 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 to 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: a traffic control technique that actively buffers and smooths the output rate in an attempt to adapt bursty traffic to the configured limits - Active Queue Management (AQM): 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 [AQM-RECO]. On the other hand, classic traffic management techniques reactively drop (or remark) packets based on queue full condition. The benchmarking scenarios for AQM are different and is outside of the scope of this testing framework. Constantine June 9, 2015 [Page 4] Internet-Draft Traffic Management Benchmarking June, 2015 Even though AQM is outside of 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 buffer bloat). Examples of these algorithms include code1 and pie (draft-ietf-aqm-code1 and draft-ietf-aqm-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 provide context to this test framework. |----------| |----------------| |--------------| |----------| | | | | | | | | |Interface | |Ingress Actions | |Egress Actions| |Interface | |Input | |(classification,| |(scheduling, | |Output | |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, DSCP, etc. In terms of marking, [RFC2697] and [RFC2698] define a single rate and dual rate, three color marker, respectively. The Metro Ethernet Forum (MEF) specifies policing and shaping in terms of Ingress and Egress Subscriber/Provider Conditioning Functions in MEF12.1 [MEF-12.1]; Ingress and Bandwidth Profile attributes in MEF10.2 [MEF-10.2] and MEF 26 [MEF-26]. 1.2 Lab Configuration and Testing Overview The following is the description of the lab set-up for the traffic management tests: +--------------+ +-------+ +----------+ +-----------+ | Transmitting | | | | | | Receiving | | Test Host | | | | | | Test Host | | |-----| Device|---->| Network |--->| | | | | Under | | Delay | | | | | | Test | | Emulator | | | | |<----| |<----| |<---| | | | | | | | | | +--------------+ +-------+ +----------+ +-----------+ As shown in the test diagram, the framework supports uni-directional and bi-directional traffic management tests (where the transmitting and receiving roles would be reversed on the return path). Constantine June 9, 2015 [Page 5] Internet-Draft Traffic Management Benchmarking June, 2015 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 load to the capacity limit of each interface. As an 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 significant size TCP window in its control loop. Also note that the Network Delay Emulator (NDE) SHOULD be passive in nature such as 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 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, 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. Constantine June 9, 2015 [Page 6] Internet-Draft Traffic Management Benchmarking June, 2015 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 SP: Strict Priority Queuing QL: Queue Length QoS: Quality of Service RTH: Receiving Test Host RTT: Round Trip Time SBB: Shaper Burst Bytes SBI: Shaper Burst Interval SR: Shaper Rate SSB: Send Socket Buffer Tc: CBS Time Interval Te: EBS Time Interval Ti Transmission Interval TTH: Transmitting Test Host Constantine June 9, 2015 [Page 7] Internet-Draft Traffic Management Benchmarking June, 2015 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, or 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 criterion, which is not within the charter of 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 scope of this framework to specify the procedure for testing multiple configurations of traffic management functions concurrently. The multitudes of possible combinations is 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. Constantine June 9, 2015 [Page 8] Internet-Draft Traffic Management Benchmarking June, 2015 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 w.r.t. 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 the 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. And finally, TCP metrics from [RFC6349] MUST be measured for each stateful test and provide the means to compare each repeated test. Even though the scope is targeted to TCP applications (i.e. Web, Email, database, etc.), the framework could be applied to SCTP in terms of test patterns. WebRTC, SS7 signaling, and 3gpp are SCTP-based applications that could be modeled with this framework to benchmark SCTP's effect on traffic management performance. Also note that currently, this framework does not address tcpcrypt (encrypted TCP) test patterns, although the metrics defined in Section 4.2 can still be used since 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. Constantine June 9, 2015 [Page 9] Internet-Draft Traffic Management Benchmarking June, 2015 4.1. Metrics for Stateless Traffic Tests Stateless traffic measurements require that sequence number and time-stamp 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 are the metrics that 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 Burst Size Achieved metric is a measure of the actual burst size received at the egress port of the DUT with no lost packets. As an example, the configured CBS of a DUT is 64KB and after the burst test, only a 63 KB can be achieved without packet loss. Then 63KB 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, KBytes, or MBytes. - 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 ingress to egress port (e.g. IP conversations), each flow must have sequence numbers within the test packets stream. [RFC6703] and [RFC2680] describe the need to establish the time threshold to wait before a packet is declared as lost, and this threshold MUST be reported with the results. This metric shall be reported as an integer number which cannot be negative. (see: http://tools.ietf.org/html/rfc6703#section-4.1) - Out of Order (OOO): in additions 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 which cannot be negative. Constantine June 9, 2015 [Page 10] Internet-Draft Traffic Management Benchmarking June, 2015 - Packet Delay (PD): the Packet Delay metric is the difference between the timestamp of the received egress port packets and the packets transmitted into the ingress port and specified in [RFC1242]. The transmitting host and receiving host time must be in time sync 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 Packet Delay Variation metric is the variation between the timestamp of the received egress port packets and 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 (negative is not possible for PDV and would indicate a measurement error). - Shaper Rate (SR): The SR represents the average DUT output rate (bps) over the test interval. The Shaper Rate is only applicable to the traffic shaping tests. - Shaper Burst Bytes (SBB): A traffic shaper will emit packets in different size "trains"; these are frames "back-to-back", respect the mandatory inter-frame gap. This metric characterizes the method by which the shaper emits traffic. Some shapers transmit larger bursts per interval, and a burst of 1 packet would apply to the extreme case of a shaper sending a CBR stream of single packets. This metric SHALL be reported in units of bytes, KBytes, or MBytes. Shaper Burst Bytes is only applicable to thetraffic shaping tests. - Shaper Burst Interval(SBI): the SBI is the time between shaper emitted bursts and is measured at the DUT egress port. This metric shall be reported as an real number of seconds. Shaper Burst Interval 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, database applications, etc. 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. Constantine June 9, 2015 [Page 11] Internet-Draft Traffic Management Benchmarking June, 2015 An example would be an interactive HTTP TTP session which 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: average of 6.5 seconds, minimum of 5.0 seconds, and maximum of 7.9 seconds. - TCP Efficiency: after the execution of the TCP Test Pattern, TCP Efficiency represents the percentage of Bytes that were not retransmitted. Transmitted Bytes - Retransmitted Bytes TCP Efficiency % = --------------------------------------- X 100 Transmitted Bytes Transmitted Bytes are the total number of TCP Bytes to be transmitted including the original and the retransmitted Bytes. These retransmitted bytes should be recorded from the sender's TCP/IP stack perspective, to avoid any misinterpretation that a reordered packet is a retransmitted packet (as may be the case with packet decode interpretation). - 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 millisecond across the entire test duration and 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 Constantine June 9, 2015 [Page 12] Internet-Draft Traffic Management Benchmarking June, 2015 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 such as IEEE 802.1Q VLAN, IEEE 802.1ad Q-in-Q, Multiprotocol Label Switching (MPLS), etc. Also, the test device must allow control of the classification techniques defined in [RFC4689] (i.e. IP address, DSCP, TOS, etc classification). 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. GigE, 10 GigE, etc.). Careful calibration of any test environment using iperf is important. At higher link speeds, it is recommended to use hardware based packet test equipment. 5.1.1 Burst Hunt with Stateless Traffic A central theme for the traffic management tests is to benchmark the specified burst parameter of traffic management function, since burst parameters of SLAs are specified in bytes. For testing efficiency, it is recommended to include a burst hunt feature, which automates the manual process of determining the maximum burst size which 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. Optionally for a policer function and 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. Constantine June 9, 2015 [Page 13] Internet-Draft Traffic Management Benchmarking June, 2015 For any test using stateful TCP test traffic, the Network Delay Emulator (NDE function from the lab set-up diagram) must be used in order to provide a meaningful BDP. As referenced in section 2, the target traffic rate and configured RTT MUST be verified independently using just the NDE for all stateful tests (to ensure the NDE can delay without loss). The TCP test host MUST be capable to generate and receive 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 adjusting both Send and Receive Socket Buffer sizes. The Socket Buffers must be large enough to fill the BDP for bulk transfer 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, etc.). 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, business applications, etc. This interactive traffic is bi-directional and can be chatty, meaning many turns in traffic communication during the course of a transaction (versus the relatively uni-directional 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 the client and server request / response behavior. The netperf-wrapper tool is a Python wrapper to run multiple simultaneous netperf instances and aggregate the results. Appendix A provides an overview of netperf / netperf-wrapper and another open source application emulation tools, 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 links speeds (e.g. 1 GigE, 10 GigE). Constantine June 9, 2015 [Page 14] Internet-Draft Traffic Management Benchmarking June, 2015 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 which 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 100ms | Browser <------------------------ Server 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 millisecond). This asynchronous, "request/response" behavior is intrinsic to most TCP based applications such as Email (SMTP), File Transfers (FTP and SMB), Database (SQL), Web Applications (SOAP), REST, etc. The impact to the network elements is due to the multitudes of Clients and the variety of bursty traffic, which stresses 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.R1002-0 v1.0" and provides examples to model the behavior of HTTP, FTP, and 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 format described in this work are the basis for the guidelines provides 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 in Appendix B. Some of these examples reflect those specified in "draft-ietf-bmwg-ca- bench-meth-04" which suggests traffic mixes for a variety of representative application profiles. Other examples are simply well-known application traffic types such as HTTP. Constantine June 9, 2015 [Page 15] Internet-Draft Traffic Management Benchmarking June, 2015 6. Traffic Benchmarking Methodology The traffic benchmarking methodology uses the test set-up from section 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 that are defined in each subsection. This comparison is not intended to compare real-time statistics, but the cumulative statistics reported after the test has completed and device counters have updated (it is common for device counters to update after a 10 second or greater interval). From a device configuration standpoint, scheduling and shaping functionality can be applied to logical ports such Link Aggregation (LAG). This would result in the same scheduling and shaping configuration applied to all the member physical ports. The focus of this draft 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). Defines 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). Defines 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-back packet testing concepts from [RFC2544] (but adapted to burst size algorithms and terminology). Also [MEF-14], [MEF-19], and [MEF-37] provide some basis 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. Constantine June 9, 2015 [Page 16] Internet-Draft Traffic Management Benchmarking June, 2015 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 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, 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, 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 for [RFC4115], consider a CBS and EBS of 64KB and CIR and EIR of 100 Mbps on a 1GigE physical link (in color-blind mode). A stateless traffic burst of 64KB would be sent into the policer at the GigE rate. This equates to approximately a 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 millisecond 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 Step: 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 seconds duration) Constantine June 9, 2015 [Page 17] Internet-Draft Traffic Management Benchmarking June, 2015 4. Excess Traffic Test: Generate bursts of greater than CBS + EBS limit traffic 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 and 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 and 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, (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 report format described in Section 6.1.1 for a single policer MUST be applied to each of the physical port policers. As an 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). Constantine June 9, 2015 [Page 18] Internet-Draft Traffic Management Benchmarking June, 2015 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 Test Summary: The first policer capacity test will benchmark a single physical port, 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, double tagged vlan, 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 non customer traffic); this includes network control protocol traffic. There is a separate policer for the other traffic. Typical deployments have 3 categories of policers; there may be some deployments with more or less than 3 categories of ingress policers. Test 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 Step: 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 seconds duration) Constantine June 9, 2015 [Page 19] Internet-Draft Traffic Management Benchmarking June, 2015 4. Excess Traffic Test: Generate bursts of greater than CBS + EBS limit traffic 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 recorded and 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, (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 a two (2) rows for each customer stream, the compliant traffic result and the excess traffic 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 the physical ports in the networking device are active. Procedure: The procedure is identical to 6.1.1, the configured parameters must be reported per port and the test report must include results per measured egress port Constantine June 9, 2015 [Page 20] Internet-Draft Traffic Management Benchmarking June, 2015 6.1.2.3 Maximum Policers on All Physical Ports Finally the third policer capacity test involves a combination of the first and second capacity test, namely maximum policers active per physical port and all physical ports are active. Procedure: Uses the procedural method from 6.1.2.1 and the configured parameters must be reported per port and the test report must include per stream results per measured egress port. 6.2. Queue and 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, the tests are divided into two sections; individual queue/scheduler function tests and then full capacity tests. 6.2.1 Queue/Scheduler Individual Tests Overview The various types of scheduling techniques include FIFO, Strict Priority (SP), Weighted Fair Queueing (WFQ) along with other variations. This test framework recommends to test at a minimum of three techniques although it is the discretion of the tester to benchmark other device scheduling algorithms. 6.2.1.1 Queue/Scheduler with Stateless Traffic Test 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 (queue length, QL) and then stateless traffic should be transmitted to test this QL. Constantine June 9, 2015 [Page 21] Internet-Draft Traffic Management Benchmarking June, 2015 A queue should be able to handle repetitive bursts with the transmission gaps proportional to the bottleneck bandwidth. This gap is referred to as the transmission interval (Ti). Ti can be defined for the traffic bursts and is based off of the QL and Bottleneck Bandwidth (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). Also note 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 Ti time interval. The metrics defined in section 4.1 shall be measured at the egress port and recorded; the primary result is to verify the BSA and 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 2 levels of priority including SP and FIFO queueing. Under a flow load greater 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 queue length (QL) and scheduling technique (FIFO, SP, etc) parameters 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 seconds duration) Report Format: The Queue/Scheduler Stateless Traffic individual report MUST contain all results for each QL/BB test run and a recommended format is as follows: Constantine June 9, 2015 [Page 22] Internet-Draft Traffic Management Benchmarking June, 2015 ******************************************************** Test Configuration Summary: Tr, Td DUT Configuration Summary: Scheduling technique, 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 set-up configuration in section 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 which 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 = 32KB RTT(min) = QL * 8 / BB and would equal 2.56 ms (and the BDP = 32KB) In this example, one (1) TCP connection with window size / SSB of 32KB would be required to test the QL of 32KB. This Bulk Transfer Test can be accomplished using iperf as described in Appendix A. Two types of TCP tests MUST be performed: Bulk Transfer test and 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 emulates application layer bursting which may occur any time during the TCP connection. Other tests types SHOULD include: Simple Web Site, Complex Web Site, Business Applications, Email, SMB/CIFS File Copy (which are also documented in Appendix B). Constantine June 9, 2015 [Page 23] Internet-Draft Traffic Management Benchmarking June, 2015 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 queue length (QL) and scheduling technique (FIFO, SP, etc) parameters 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 be also be configurable * The test generator MUST be capable of generating precise TCP test patterns for each application specified, to ensure repeatable results. 3. Generate application traffic between the ingress (client side) and egress (server side) ports of the DUT and measure application throughput the metrics (TTPET, TCP Efficiency, and Buffer Delay), per application stream and at the ingress and egress port (across the entire Td, default 60 seconds duration). Concerning application measurements, a couple of items require clarification. An application session may be comprised of a single TCP connection or multiple TCP connections. For the single TCP connection application sessions, the application thoughput / metrics have a 1-1 relationship to the TCP connection measurements. If an application session (i.e. 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 mulitlple 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 and provides a measure of "goodput" during each test. Constantine June 9, 2015 [Page 24] Internet-Draft Traffic Management Benchmarking June, 2015 Reporting Format: The Queue/Scheduler Stateful Traffic individual report MUST contain all results for each traffic scheduler and QL/BB test run and a recommended format is as follows: ******************************************************** Test Configuration Summary: Tr, Td DUT Configuration Summary: Scheduling technique, BB and QL Application Mixture and Intensities: this is the percent configured of 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) - Per Application Throughout (bps) and TTPET - Per Application Bytes In and Bytes Out - Per Application TCP Efficiency, and Buffer Delay ******************************************************** 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. This test 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 scheduler / queue capacity test, multiple queues per port will be tested on a single physical port. In this case, all the queues (typically 8) are active on a single physical port. Traffic from multiple ingress physical ports are directed to the same egress physical port which 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. Constantine June 9, 2015 [Page 25] Internet-Draft Traffic Management Benchmarking June, 2015 6.2.2.1.1 Strict Priority on Egress Port Test Summary: For this test, Strict Priority (SP) scheduling on the egress physical port should be tested and the benchmarking methodology specified in section 6.2.1.1 and 6.2.1.2 (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 from 6.2.1.1 and 6.2.1.2 MUST also include: Configuration: - The number of physical ingress ports active during the test - The classication 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 + Weighted Fair Queue (WFQ) on Egress Port Test Summary: For this test, Strict Priority (SP) and Weighted Fair Queue (WFQ) should be enabled simultaneously in the scheduler but on a single egress port. The benchmarking methodology specified in Section 6.2.1.1 and 6.2.1.2 (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 from 6.2.1.1 and 6.2.1.2 MUST also include: Configuration: - The number of physical ingress ports active during the test - The classication 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 queue). Constantine June 9, 2015 [Page 26] Internet-Draft Traffic Management Benchmarking June, 2015 Example: - Egress Port SP Queue: throughput and metrics for ingress streams 1-n - Egress Port WFQ Queue: 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 are directed to the same egress physical port, which will cause oversubscription on the egress physical port. Also, the same amount of traffic is directed to each egress physical port. The benchmarking methodology specified in Section 6.2.1.1 and 6.2.1.2 (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 from 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 classication 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 Traffic from multiple ingress physical ports are directed to all queues of each egress physical port, which will cause oversubscription on the egress physical ports. Also, the same amount of traffic is directed to each egress physical port. The benchmarking methodology specified in Section 6.2.1.1 and 6.2.1.2 (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. Constantine June 9, 2015 [Page 27] Internet-Draft Traffic Management Benchmarking June, 2015 Since this is a capacity test, the configuration and report results format from 6.2.1.1 and 6.2.1.2 MUST also include: Configuration: - The number of physical ingress ports active during the test - The classication 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 Queue: 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 Queue: throughput and metrics for ingress streams 1-n 6.3. Shaper tests A traffic shaper is memory based like a queue, but with the added intelligence of an active traffic scheduler. The same concepts from section 6.2 (Queue testing) can be applied to testing 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 Overview A traffic shaper generally has three (3) components that can be configured: - Ingress Queue bytes - Shaper Rate, 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 Shaper Rate and Bc/Be parameters. Shapers generally transmit into policers, so the idea is for the emitted traffic to conform to the policer's limits. Constantine June 9, 2015 [Page 28] Internet-Draft Traffic Management Benchmarking June, 2015 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 Ti (Time interval) must be large enough so that the Shaper Rate is not exceeded. An example will clarify single and multiple burst test cases. In the 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 Shaper Rate (SR) = 50 Mbps, and both Bc/Be 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 time interval between the 512,000 byte bursts must not exceed the Shaper Rate. The time interval (Ti) must adhere to a similar formula as described in section 6.2.1.1 for queues, namely: Ti = Ingress Queue x 8 / Shaper Rate For the example from the previous paragraph, Ti between bursts must be greater than 82 millisecond (512,000 bytes x 8 / 50,000,000 bps). This yields an average rate of 50 Mbps so that an Input Queue would not overflow. Test Metrics: - The metrics defined in section 4.1 (LP, OOS, PDV, SR, SBB, SBI) SHALL be measured at the egress port and recorded. Procedure: 1. Configure the DUT shaper ingress queue length (QL) and shaper egress rate parameters (SR, Bc, Be) parameters 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, SBI) at the egress port and across the entire Td (default 30 seconds duration) Constantine June 9, 2015 [Page 29] Internet-Draft Traffic Management Benchmarking June, 2015 Report Format: The Shaper Stateless Traffic individual report MUST contain all results for each QL/SR test run and 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, 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 set-up configuration in section 2. The BDP of the TCP test traffic must be calculated as described in section 6.2.2. To properly stress network buffers and the traffic shaping function, the cumulative TCP window should exceed the BDP which will stress the shaper. BDP factors of 1.1 to 1.5 are recommended, but the values are the discretion of the tester and should be documented. The cumulative TCP Window Sizes* (RWND at the receiving end & CWND at the transmitting end) equates to: TCP window size* for each connection x number of connections * as described in section 3 of [RFC6349], the SSB MUST be large enough to fill the BDP Example, if the BDP is equal to 256 Kbytes and a connection size of 64Kbytes is used for each connection, then it would require four (4) connections to fill the BDP and 5-6 connections (over subscribe the BDP) to stress test the traffic shaping function. Two types of TCP tests MUST be performed: Bulk Transfer test and 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 emulates application layer bursting which may any time during the TCP connection. Constantine June 9, 2015 [Page 30] Internet-Draft Traffic Management Benchmarking June, 2015 Other tests types SHOULD include: Simple Web Site, Complex Web Site, Business Applications, Email, SMB/CIFS File Copy (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 queue length (QL) and shaper egress rate parameters (SR, Bc, Be) parameters 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 be also be configurable * The test generator MUST be capable of generating precise TCP test patterns for each application specified, to ensure repeatable results. 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 port (across the entire Td, default 30 seconds duration). Reporting Format: The Shaper Stateful Traffic individual report MUST contain all results for each traffic scheduler and QL/SR test run and a recommended format is as follows: ******************************************************** Test Configuration Summary: Tr, Td DUT Configuration Summary: Ingress Burst Rate, QL, SR Application Mixture and Intensities: this is the percent configured of each application type Constantine June 9, 2015 [Page 31] Internet-Draft Traffic Management Benchmarking June, 2015 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) - Per Application Throughout (bps) and TTPET - Per Application Bytes In and Bytes Out - Per Application TCP Efficiency, and Buffer Delay ******************************************************** 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. This test 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, all physical ports active. Traffic from multiple ingress physical ports are directed to the same egress physical port and this will cause oversubscription on the egress physical port. Also, the same amount of traffic is directed to each egress physical port. The benchmarking methodology specified in Section 6.3.1 (procedure, metrics, and reporting format) should be applied here. Since this is a capacity test, the configuration and report results format from 6.3.1 MUST also include: Configuration: - The number of physical ingress ports active during the test - The classication 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 ports 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 Constantine June 9, 2015 [Page 32] Internet-Draft Traffic Management Benchmarking June, 2015 described in per port shaping test (previous section) 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 methodology specified in Section 6.3.1 (procedure, metrics, and reporting format) should be applied here. Since this is a capacity test, the configuration and report results format from 6.3.1 MUST also include: Configuration: - The number of physical ingress ports active during the test - The classication 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 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: And for the third shaper capacity test (which is a combination of the tests in the previous two sections),all queues will be actively shaping and all physical ports active. The benchmarking methodology specified in Section 6.3.1 (procedure, metrics, and reporting format) should be applied here. Since this is a capacity test, the configuration and report results format from 6.3.1 MUST also include: Configuration: - The number of physical ingress ports active during the test - The classication 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 and per queue parameters(QL, SR, Bc, Be) Constantine June 9, 2015 [Page 33] Internet-Draft Traffic Management Benchmarking June, 2015 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 the scope 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 which may be useful to test under capacity as well: - Policers on ingress and queuing on egress - Policers on ingress and shapers on egress (not intended for a flow to be policed then shaped, these would be two different flows tested at the same time) - etc. The test procedures and reporting formatting from the previous sections 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. IANA Considerations This document does not REQUIRE an IANA registration for ports dedicated to the TCP testing described in this document. Constantine June 9, 2015 [Page 34] Internet-Draft Traffic Management Benchmarking June, 2015 9. References 9.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC2119, March 1997. [RFC1242] S. Bradner, "Benchmarking Terminology for Network Interconnection Devices," RFC1242 July 1991 [RFC2544] S. Bradner, "Benchmarking Methodology for Network Interconnect Devices," RFC2544 March 1999 [RFC3148] M. Mathis et al., A Framework for Defining Empirical Bulk Transfer Capacity Metrics," RFC3148 July 2001 [RFC5481] A. Morton et al., "Packet Delay Variation Applicability Statement," RFC5481 March 2009 [RFC6703] A. Morton et al., "Reporting IP Network Performance Metrics: Different Points of View." RFC 6703 August 2012 [RFC2680] G. Almes et al., "A One-way Packet Loss Metric for IPPM," RFC2680 September 1999 [RFC4689] S. Poretsky et al., "Terminology for Benchmarking Network-layer Traffic Control Mechanisms," RFC4689, October 2006 [RFC4737] A. Morton et al., "Packet Reordering Metrics," RFC4737, February 2006 [RFC4115] O. Aboul-Magd et al., "A Differentiated Service Two-Rate, Three-Color Marker with Efficient Handling of in-Profile Traffic." RFC4115 July 2005 [RFC6349] Barry Constantine et al., "Framework for TCP Throughput Testing," RFC6349, August 2011 9.2. Informative References [RFC2697] J. Heinanen et al., "A Single Rate Three Color Marker," RFC2697, September 1999 [RFC2698] J. Heinanen et al., "A Two Rate Three Color Marker, " RFC2698, September 1999 [AQM-RECO] Fred Baker et al., "IETF Recommendations Regarding Active Queue Management," August 2014, https://datatracker.ietf.org/doc/draft-ietf-aqm- recommendation/ Constantine June 9, 2015 [Page 35] Internet-Draft Traffic Management Benchmarking June, 2015 [MEF-10.2] "MEF 10.2: Ethernet Services Attributes Phase 2," October 2009, http://metroethernetforum.org/PDF_Documents/ technical-specifications/MEF10.2.pdf [MEF-12.1] "MEF 12.1: Carrier Ethernet Network Architecture Framework -- Part 2: Ethernet Services Layer - Base Elements," April 2010, https://www.metroethernetforum.org/Assets/Technical _Specifications/PDF/MEF12.1.pdf [MEF-26] "MEF 26: External Network Network Interface (ENNI) - Phase 1,"January 2010, http://www.metroethernetforum.org /PDF_Documents/technical-specifications/MEF26.pdf [MEF-14] "Abstract Test Suite for Traffic Management Phase 1, https://www.metroethernetforum.org/Assets /Technical_Specifications/PDF/MEF_14.pdf [MEF-19] "Abstract Test Suite for UNII Type 1", https://www.metroethernetforum.org/Assets /Technical_Specifications/PDF/MEF_19.pdf [MEF-37] "Abstract Test Suite for ENNI", https://www.metroethernetforum.org/Assets /Technical_Specifications/PDF/MEF_37.pdf 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),uperf, TMIX, TCP-incast-generator, and D-ITG (Distributed Internet Traffic Generator). Iperf can generate UDP 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 uni-directional and bi-directional 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 are 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), the number of connections, the packet size, TCP port and the test duration can be controlled. A report of bytes transmitted and throughput achieved are provided by the iperf sender, while TCP-incast-generator and D-ITG provide even more statistics. Constantine June 9, 2015 [Page 36] Internet-Draft Traffic Management Benchmarking June, 2015 Netperf is a software application that provides network bandwidth testing between two hosts on a network. It supports Unix domain sockets, TCP, SCTP, DLPI 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 aggregate the results. uperf uses a description (or model) of an application mixture and the tool generates the load according to the model desciptor. uperf is more flexible than Netperf in it's ability to generate request / response application behavior within a single TCP connection. The application model descriptor can be based off of empirical data, but currently the import of packet captures is not directly supported. Tmix is another application traffic emulation tool and 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 environment, TMix also runs on Linux hosts. These open source tool's traffic generation capabilities facilitate the emulation of the TCP test patterns which are 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 or multiple TCP connections(s). 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 from "3GPP2 C.R1002-0 v1.0" is referenced (Table 4.1.3.2.1) 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) Constantine June 9, 2015 [Page 37] Internet-Draft Traffic Management Benchmarking June, 2015 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 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. - Inter-active Patterns: While Web site patterns are inter-active to a degree, they mainly emulate the downloading of various complexity web sites. Inter-active patterns are more chatty in nature since there is alot of user interaction with the servers. Examples include business applications such as Peoplesoft, Oracle and consumer applications such as Facebook, IM, etc. For the inter- active patterns, the packet capture technique was used to characterize some business applications and also the email application. Constantine June 9, 2015 [Page 38] Internet-Draft Traffic Management Benchmarking June, 2015 In summary, an inter-active 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 inter-active applications Again using packet capture as a means to characterize, the following table reflects the guidelines for Simple Business Application, Complex Business Application, eCommerce, and Email Send / Receive: Simple Complex Parameter Biz. App. Biz. App 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 Constantine June 9, 2015 [Page 39] Internet-Draft Traffic Management Benchmarking June, 2015 Complex Business Application, eCommerce, and Email Send / Receive (continued): Simple Complex Parameter Biz. App. Biz. App eCommerce* Email -------------------------------------------------------------------- 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 from "SPECweb2009" (need proper reference) ** The client and server processing time is distributed across the transmission / receipt of all of messages. Client processing time consists mainly of the delay between user interactions (not machine processing). And 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 th file transfer. Constantine June 9, 2015 [Page 40] Internet-Draft Traffic Management Benchmarking June, 2015 Again using packet capture as a means to characterize the following table reflects the guidelines for SMB/CIFS file copy: SMB 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 64KB 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 the document. We would also like to thank Scott Bradner for providing guidance early in the drafts conception in the area of benchmarking scope of traffic management functions. Additionally, we would like to thank Tim Copley for this original input and David Taht, Gory Erg, Toke Hoiland-Jorgensen for their review and input for the AQM group. And for the formal reviews of this document, we would like to thank Gilles Forget, Vijay Gurbani, Reinhard Schrage, and Bhuvaneswaran Vengainathan Constantine June 9, 2015 [Page 41] Internet-Draft Traffic Management Benchmarking June, 2015 Authors' Addresses Barry Constantine JDSU, Test and Measurement Division Germantown, MD 20876-7100, USA Phone: +1 240 404 2227 Email: barry.constantine@jdsu.com Ram(Ramki) Krishnan Dell Inc. Santa Clara, CA 95054, USA Phone: +001-408-406-7890 Email: ramkri123@gmail.com Constantine June 9, 2015 [Page 42]