Internet DRAFT - draft-constantine-bmwg-traffic-management

draft-constantine-bmwg-traffic-management



Network Working Group                                     B. Constantine
Internet Draft                                                      JDSU
Intended status: Informational                                 T. Copley
Expires: December 2014                                           Level-3
June 25, 2014                                                R. Krishnan
                                                  Brocade Communications



                      Traffic Management Benchmarking
            draft-constantine-bmwg-traffic-management-04.txt


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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.

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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.......................9
      4.2. Metrics for Stateful Traffic Tests.......................11
   5. Tester Capabilities...........................................11
      5.1. Stateless Test Traffic Generation........................11
      5.2. Stateful Test Pattern Generation.........................12
         5.2.1. TCP Test Pattern Definitions........................13
   6. Traffic Benchmarking Methodology..............................15
      6.1. Policing Tests...........................................15
      6.1.1 Policer Individual Tests................................15
          6.1.2 Policer Capacity Tests..............................16
          6.1.2.1 Maximum Policers on Single Physical Port..........16
          6.1.2.2 Single Policer on All Physical Ports..............17
          6.1.2.3 Maximum Policers on All Physical Ports............17
      6.2. Queue/Scheduler Tests....................................17
      6.2.1 Queue/Scheduler Individual Tests........................17
          6.2.1.1 Testing Queue/Scheduler with Stateless Traffic....17
          6.2.1.2 Testing Queue/Scheduler with Stateful Traffic.....18
        6.2.2 Queue / Scheduler Capacity Tests......................19
          6.2.2.1 Multiple Queues / Single Port Active..............19
          6.2.2.1.1 Strict Priority on Egress Port..................19
          6.2.2.1.2 Strict Priority + Weighted Fair Queue (WFQ).....19
          6.2.2.2 Single Queue per Port / All Ports Active..........19
          6.2.2.3 Multiple Queues per Port, All Ports Active........20
      6.3. Shaper tests.............................................20
        6.3.1 Shaper Individual Tests...............................20
          6.3.1.1 Testing Shaper with Stateless Traffic.............20
          6.3.1.2 Testing Shaper with Stateful Traffic..............21
        6.3.2 Shaper Capacity Tests.................................22
          6.3.2.1 Single Queue Shaped, All Physical Ports Active....22
          6.3.2.2 All Queues Shaped, Single Port Active.............22
          6.3.2.3 All Queues Shaped, All Ports Active...............22
      6.4. Concurrent Capacity Load Tests...........................24
   7. Security Considerations.......................................24
   8. IANA Considerations...........................................24
   9. Conclusions...................................................24
   10. References...................................................24
      10.1. Normative References....................................25
      10.2. Informative References..................................25
   11. Acknowledgments..............................................25

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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. 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 benchmarking, Layer 4 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 (i.e. VLAN, 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 contracted limits, the traffic is either dropped or 
    remarked and sent 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 meters the output rate in an attempt to adapt bursty traffic
    to the configured limits
  - Active Queue Management (AQM): monitors the status of internal 
    queues and actively drops (or re-marks) packets, which causes hosts
    using congestion-aware protocols to back-off and in turn can 
    alleviate queue congestion.  Note that AQM is outside of the scope 
	of this testing framework.

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   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   |   |          |
   |          |   |                |   | re-marking)  |   |          |
   |----------|   |----------------|   |--------------|   |----------|

   Figure 1: Generic Traffic Management capabilities of a Network Device

   Ingress actions such as classification are defined in RFC 4689 and 
   include IP addresses, port numbers, DSCP, etc.  In terms of marking,
   RFC 2697 and RFC 2698 define a single rate and dual rate, three color 
   marker, respectively.
   
   The MEF specifies policing and shaping in terms of Ingress and Egress 
   Subscriber/Provider Conditioning Functions in MEF12.1; Ingress and
   Bandwidth Profile attributes in MEF 10.2 and MEF 26.
   
1.2 DUT 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 |
    |              |-----| DUT   |---->| Network  |--->|           |
    |              |     |       |     | Delay    |    |           |
    |              |     |       |     | Emulator |    |           |
    |              |<----|       |<----|          |<---|           |
    |              |     |       |     |          |    |           |
    +--------------+     +-------+     +----------+    +-----------+

   As shown in the test diagram, the framework supports uni-directional 
   and bi-directional traffic management tests.

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   This testing framework describes the tests and metrics for each of 
   the following traffic management functions:
   - Policing
   - Queuing / Scheduling
   - Shaping
   
   The tests are divided into individual tests 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 full load.
   This involves concurrent testing of multiple interfaces with the 
   specific traffic management function enabled, and doing so to the 
   capacity limit of each interface.  
   
   As an example: a device is specified to be capable of shaping on all
   of it's egress ports. The individual test would first be conducted to
   benchmark the advertised 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 a requirement for the TCP
   stateful tests, which require network delay to allow TCP to fully
   open the TCP window.  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 that 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 the NDE should be used in "full pipe" delay mode. 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 BDPs for the TCP stateful tests.
   
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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 RFC 2119 [RFC2119].

   The following acronyms are used:

   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

   RED: Random Early Discard

   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
   
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   Ti Transmission Interval
   
   TTP: TCP Test Pattern
   
   TTPET: TCP Test Pattern Execution Time

   WRED: Weighted Random Early Discard

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 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, this framework describes 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 traffic management functions concurrently.  The 
   multitudes of possible combinations is almost unbounded and the 
   ability to identify functional "break points" would be most times 
   impossible.

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   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.  Traffic 
   management specifications largely do not exist and this is a prime
   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.)

   And finally, this framework will provide references to open source
   tools that can be used to provide stateless and/or stateful
   traffic generation emulation.

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 segment layer metrics used for the stateful traffic 
   testing.

4.1.  Metrics for Stateless Traffic Tests

   For the stateless traffic tests, the metrics are defined at the layer
   3 packet level versus layer 2 packet level for consistency.

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   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, RFC 4689 provides
   recommendations for sequence tracking along with definitions of 
   in-sequence and out-of-order packets.
   
   The following are the metrics to be used 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.   

   - 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.  RFC 4737 and RFC 2680 describe the need to
   to establish the time threshold to wait before a packet is declared 
   as lost. packet as lost, and this threshold MUST be reported with 
   the results.

   - Out of Sequence (OOS): in additions to the LP metric, the test
   packets must be monitored for sequence and the out-of-sequence (OOS)
   packets. RFC 4689 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 RFC 4737 and RFC 2680.

   - 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 RFC 2285. 

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   - Packet Delay Variation (PDV): the Packet Delay Variation metric is
   the variation between the timestamp of the received egress port
   packets and specified in RFC 5481.
   
   - Shaper Rate (SR): the Shaper Rate is only applicable to the 
   traffic shaping tests.  The SR represents the average egress output
   rate (bps) over the test interval.
   
   - Shaper Burst Bytes (SBB): the Shaper Burst Bytes is 
   only applicable to the traffic shaping tests.  A traffic shaper will
   emit packets in different size "trains" (bytes back-to-back).  This
   metric characterizes the method by which the shaper emits traffic.
   Some shapers transmit larger bursts per interval, while other shapers
   may transmit a single frame at the CIR rate (two extreme examples).
   
   - Shaper Burst Interval(SBI):  the interval is only applicable to the 
   traffic shaping tests and again is the time between a shaper emitted
   bursts.
   
4.2. Metrics for Stateful Traffic Tests

   The stateful metrics will be based on RFC 6349 TCP metrics and will
   include:

   - TCP Test Pattern Execution Time (TTPET): RFC 6349 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.
   
   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).   

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   - 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 RFC 6349.  Referencing RFC 6349, 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 RFC 6349, 
    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

5.1. Stateless Test Traffic Generation

   The test set must be capable of generating traffic at up to the
   link speed of the DUT.  The test set must be calibrated to verify
   that it will not drop any packets.  The test set's inherent PD and PDV
   must also be calibrated and subtracted from the PD and PDV metrics.
   The test set must support the encapsulation to be tested such as
   VLAN, Q-in-Q, MPLS, etc.  Also, the test set must allow control of 
   the classification techniques defined in RFC 4689 (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.

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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 RFC 6349.  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
   (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 (i.e. OS version, i.e. LINUX OS kernel using TCP New Reno,
   TCP options supported, etc.).
   

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   While RFC 6349 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.

   The test device must not only support bulk TCP transfer application
   traffic but also 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
   open source tool "Flowgrind" (referenced in Appendix A) is 
   client-server based and emulates interactive applications at the TCP 
   layer.  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).

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


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   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.
   
   There are two (2) techniques recommended by this framework to develop 
   standard TCP test patterns for traffic management benchmarking.

   The first technique involves modeling, which have been described in 
   "3GPP2 C.R1002-0 v1.0" and describe 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 Flowgrind tool (Appendix A)
   supports many of the distributions and is a good choice as long as 
   the processing limits of the server platform are taken into 
   consideration.

   The second technique is to conduct packet captures of the
   applications to test and then to statefully play the application back
   at the TCP layer.  The TCP playback includes the request byte size,
   response byte size, and inter-message gaps at both the client and the
   server.  The advantage of this method is that very realistic test
   patterns can be defined based on real world application traffic.

   This framework does not specify a fixed set of TCP test patterns, but
   does provide recommended test cases 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.
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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 be run
   for a minimum test time of 5 minutes.  
   
   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.

6.1. Policing Tests

   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 RFC 2544 (but adapted
   to burst size algorithms and terminology).  Also MEF-14,19,37 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.
   
   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

   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.

   The policer test shall test a policer as defined by RFC 4115 or 
   MEF 10.2, depending upon the equipment's specification. As an example
   for RFC 4115, 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.   
   
   The metrics defined in section 4.1 shall be measured at the egress
   port and recorded.
   
   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 police at the specified CBS/EBS values.
   
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   For this portion of the test, the CBS/EBS value should be incremented
   by 1000 bytes higher than the configured CBS and that the egress port
   measurements must show that the excess packets are dropped.

   Additional tests beyond the simple color-blind example might include:
   color-aware mode, configurations where EIR is greater than CIR, etc.
   
6.1.2 Policer Capacity Tests

   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. 

   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).  

   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 methodology described 
   in Section 6.1.1 for a single policer should be applied to each of 
   the physical port policers.
   
6.1.2.1 Maximum Policers on Single Physical Port
   
   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.

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6.1.2.2 Single Policer on All Physical Ports
   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. 

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 .

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's 
   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

   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 Testing Queue/Scheduler with Stateless Traffic

   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.

   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.
   
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   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.   

6.2.1.2 Testing Queue/Scheduler with Stateful Traffic

   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 RFC 6349, 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 millisecond (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).

   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.
   

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6.2.2 Queue / Scheduler Capacity Tests
   
   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. 

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.
   
6.2.2.1.1 Strict Priority on Egress Port

   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 should be applied here.  For a given 
   priority, each ingress physical port should get a fair share of
   the egress physical port bandwidth.

6.2.2.1.2 Strict Priority + Weighted Fair Queue (WFQ) on Egress Port
   
   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
   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.

6.2.2.2 Single Queue per Port / All Ports Active

   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 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.

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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 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.

6.3. Shaper tests

   A traffic shaper is memory based like a queue, but with the added
   intelligence of an active shaping element. 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

   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.
   
   The stateless and stateful traffic test sections describe the
   techniques to transmit bursts into the DUT's ingress port
   and the metrics to benchmark at the shaper egress port.

6.3.1.1 Testing Shaper with Stateless Traffic

   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.
   
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   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 = 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.  The egress port metrics from section 4.1
   will be recorded with particular emphasis on the LP, PDV, SBB, and
   SBI metrics.
   
   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

   So 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.

6.3.1.2 Testing Shaper with Stateful Traffic

   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.
   
   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).

   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.
   
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6.3.2 Shaper Capacity Tests

   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.

   For all of the capacity tests, the benchmarking methodology described 
   in Section 6.3.1 for a single shaper should be applied to each of the 
   physical port and/or queue shapers.

6.3.2.1 Single Queue Shaped, All Physical Ports Active
   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 described in Section 6.3.1 should be 
   applied to each of the physical ports. Each ingress physical port 
   should get a fair share of the egress physical port bandwidth. 
   
6.3.2.2 All Queues Shaped, Single Port Active
   The second shaper capacity test is conducted with all queues actively
   shaping on a single physical port. The benchmarking methodology
   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.

6.3.2.3 All Queues Shaped, All Ports Active
   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. 

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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.
  
Appendix A: Open Source Tools for Traffic Management Testing

   This framework specifies that stateless and stateful behaviors should
   both be tested.  Two (2) open source tools that can be used are iperf
   and Flowgrind to accomplish many of the tests proposed in this 
   framework.

   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.

   The TCP mode 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.

   Flowgrind is a distributed network performance measurement tool.
   Using the flowgrind controller, tests can be setup between hosts
   running flowgrind.  For the purposes of this traffic management
   testing framework, the key benefit of Flowgrind is that it can
   emulate non-bulk transfer applications such as HTTP, Email, etc.
   This is due to fact that Flowgrind supports the concept of request
   and response behavior while iperf does not.

   Traffic generation options include the request size, response size,
   inter-request gap, and response time gap.  Additionally, various
   distribution types are supported including constant, normal,
   exponential, pareto, etc.  These traffic generation parameters
   facilitate the emulation of some of the TCP test patterns
   which are discussed in Appendix B.
   
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   Since these tools are software based, the host hardware must be
   qualified as capable of generating the target traffic loads
   without packet loss and within the packet delay variation threshold.

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 RFC 6349 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)
	   
    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
   
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   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.
   
   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

    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).
   
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   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.
   
   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.
	
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7. Security Considerations

8. IANA Considerations

9. Conclusions

10. References

10.1. Normative References

   [1]   Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [2]   Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax
         Specifications: ABNF", RFC 2234, Internet Mail Consortium and
         Demon Internet Ltd., November 1997.

   [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for
             Syntax Specifications: ABNF", RFC 2234, Internet Mail
             Consortium and Demon Internet Ltd., November 1997.

10.2. Informative References

11. Acknowledgments


Authors' Addresses

   Barry Constantine

   JDSU, Test and Measurement Division

   Germantown, MD 20876-7100, USA

   Phone: +1 240 404 2227

   Email: barry.constantine@jdsu.com


   Timothy Copley

   Level 3 Communications

   14605 S 50th Street

   Phoenix, AZ 85044

   Email: Timothy.copley@level3.com


   Ram Krishnan

   Brocade Communications

   San Jose, 95134, USA

   Phone: +001-408-406-7890

   Email: ramk@brocade.com

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