[Search] [txt|pdfized|bibtex] [Tracker] [Email] [Diff1] [Diff2] [Nits]
Versions: 00 01 02 03 04                                                
Network Working Group                                          T. Player
Internet-Draft                                    Spirent Communications
Intended status: Informational                                 D. Newman
Expires: April 22, 2011                                     Network Test
                                                        October 19, 2010


Bridge Out: Benchmarking Methodology Extensions for Data Center Bridging
                                Devices
                  draft-player-dcb-benchmarking-03.txt

Abstract

   Existing benchmarking methodologies are based on the assumption that
   networking devices will impartially drop network traffic at their
   performance limits.  Data Center Bridging (DCB) devices, however,
   will attempt to throttle prioritized traffic from network endpoints
   before those limits are reached in order to minimize the probability
   of frame loss for high value traffic.  Hence, existing methodologies
   based around indiscriminate frame loss are inappropriate for DCB
   devices.  This document takes the basic benchmarking ideas based on
   loss and extends them to support "lossless" Ethernet devices.

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 April 22, 2011.

Copyright Notice

   Copyright (c) 2010 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



Player & Newman          Expires April 22, 2011                 [Page 1]


Internet-Draft              DCB Benchmarking                October 2010


   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.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Requirements . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  General Considerations . . . . . . . . . . . . . . . . . . . .  5
     4.1.  Classifications  . . . . . . . . . . . . . . . . . . . . .  5
     4.2.  Congestion . . . . . . . . . . . . . . . . . . . . . . . .  5
     4.3.  Test Traffic . . . . . . . . . . . . . . . . . . . . . . .  6
     4.4.  Tester Capabilities  . . . . . . . . . . . . . . . . . . .  6
       4.4.1.  Frame Formats  . . . . . . . . . . . . . . . . . . . .  6
       4.4.2.  Pause Response Time  . . . . . . . . . . . . . . . . .  7
   5.  Test Setup . . . . . . . . . . . . . . . . . . . . . . . . . .  7
     5.1.  Test Traffic . . . . . . . . . . . . . . . . . . . . . . .  7
       5.1.1.  Traffic Classification . . . . . . . . . . . . . . . .  7
       5.1.2.  Trial Duration . . . . . . . . . . . . . . . . . . . .  7
       5.1.3.  Frame Measurements . . . . . . . . . . . . . . . . . .  7
       5.1.4.  Frame Sizes  . . . . . . . . . . . . . . . . . . . . .  8
       5.1.5.  Burst Sizes  . . . . . . . . . . . . . . . . . . . . .  8
   6.  Benchmarking Tests . . . . . . . . . . . . . . . . . . . . . .  9
     6.1.  Pause Response Time  . . . . . . . . . . . . . . . . . . .  9
       6.1.1.  Objective  . . . . . . . . . . . . . . . . . . . . . .  9
       6.1.2.  Setup Parameters . . . . . . . . . . . . . . . . . . .  9
       6.1.3.  Procedure  . . . . . . . . . . . . . . . . . . . . . . 10
       6.1.4.  Measurements . . . . . . . . . . . . . . . . . . . . . 10
       6.1.5.  Reporting Format . . . . . . . . . . . . . . . . . . . 11
     6.2.  Queueput . . . . . . . . . . . . . . . . . . . . . . . . . 11
       6.2.1.  Objective  . . . . . . . . . . . . . . . . . . . . . . 11
       6.2.2.  Setup Parameters . . . . . . . . . . . . . . . . . . . 11
       6.2.3.  Procedure  . . . . . . . . . . . . . . . . . . . . . . 11
       6.2.4.  Measurements . . . . . . . . . . . . . . . . . . . . . 12
       6.2.5.  Reporting Format . . . . . . . . . . . . . . . . . . . 12
     6.3.  Maximum Forwarding Rate  . . . . . . . . . . . . . . . . . 12
       6.3.1.  Objective  . . . . . . . . . . . . . . . . . . . . . . 12
       6.3.2.  Setup Parameters . . . . . . . . . . . . . . . . . . . 12
       6.3.3.  Procedure  . . . . . . . . . . . . . . . . . . . . . . 13
       6.3.4.  Measurements . . . . . . . . . . . . . . . . . . . . . 13
       6.3.5.  Reporting Format . . . . . . . . . . . . . . . . . . . 14
     6.4.  Back-off . . . . . . . . . . . . . . . . . . . . . . . . . 14
       6.4.1.  Objective  . . . . . . . . . . . . . . . . . . . . . . 14



Player & Newman          Expires April 22, 2011                 [Page 2]


Internet-Draft              DCB Benchmarking                October 2010


       6.4.2.  Setup Parameters . . . . . . . . . . . . . . . . . . . 14
       6.4.3.  Procedure  . . . . . . . . . . . . . . . . . . . . . . 15
       6.4.4.  Measurements . . . . . . . . . . . . . . . . . . . . . 15
       6.4.5.  Reporting Format . . . . . . . . . . . . . . . . . . . 15
     6.5.  Back-to-Back . . . . . . . . . . . . . . . . . . . . . . . 15
       6.5.1.  Objective  . . . . . . . . . . . . . . . . . . . . . . 15
       6.5.2.  Setup Parameters . . . . . . . . . . . . . . . . . . . 15
       6.5.3.  Procedure  . . . . . . . . . . . . . . . . . . . . . . 16
       6.5.4.  Measurements . . . . . . . . . . . . . . . . . . . . . 16
       6.5.5.  Reporting Format . . . . . . . . . . . . . . . . . . . 17
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 17
   8.  IANA Consdierations  . . . . . . . . . . . . . . . . . . . . . 17
   9.  Normative References . . . . . . . . . . . . . . . . . . . . . 17
   Appendix A.  Acknowledgements  . . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 18




































Player & Newman          Expires April 22, 2011                 [Page 3]


Internet-Draft              DCB Benchmarking                October 2010


1.  Introduction

   This document is intended to provide a methodology for benchmarking
   Data Center Bridging (DCB) devices that support Priority-based Flow
   Control (PFC).  It extends the methodologies already defined in
   [RFC2544] and [RFC2889].

   This memo primarily deals with devices which use Priority-based Flow
   Control, as defined in IEEE specification 802.1Qbb, to actively
   manage the transmission rate of multiple classes of traffic in order
   to minimize forwarding delay and frame loss for high priority
   traffic.


2.  Requirements

   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].


3.  Terminology

   As the terminology used by [RFC4689] is specific to IP layer testing,
   a number of existing terms require clarification when used in the DCB
   benchmarking context.  Additionally, a number of new terms are also
   presented to clarify concepts not clearly defined within the scope of
   [RFC4689].

      Classification: As stated in [RFC4689], Classification is the
      selection of packets according to defined rules.  In the context
      of DCB benchmarking, the Classification criterion is the value of
      the 802.1p priority code point field in the 802.1Q VLAN header of
      an Ethernet frame.

      Classification Group: A collection of traffic streams that belong
      to a single Classification.  A Conformance Vector MAY be
      associated with a Classification Group.

      Classification Profile: The set of all Classification Groups
      involved in a benchmarking test.

      Conformance Vector: A set of measurable stream result bounds, e.g.
      latency, jitter, sequencing, etc., that specify whether a frame is
      Conformant or Non-conformant.  Conformance vectors are optional
      for all DCB benchmarking tests.





Player & Newman          Expires April 22, 2011                 [Page 4]


Internet-Draft              DCB Benchmarking                October 2010


      Congestion Management: In the context of DCB benchmarking,
      Congestion Management occurs when the DUT/SUT transmits Priority-
      based Flow Control (PFC) Pause frames.

      Forwarding Congestion: In the context of DCB benchmarking,
      Forwarding Congestion is extended to include the observation of
      PFC pause frame transmissions from the DUT.

      Intended Load: In this document, the Intended Load refers to the
      summation of the Intended Vectors for all Classification Groups.

      Offered Load: In this document, the Offered Load refers to the
      summation of the Offered Vectors for all Classification Groups.

      Queue Congestion: Queue congestion occurs when a DUT/SUT uses
      Congestion Management on a set of traffic Classifications.  The
      congestion Classifications correspond to the congested queues in
      the DUT/SUT.

      Queueput: The maximum Offered Load than can be transmitted into a
      DUT/SUT such that every transmitted frame matches a specific
      Classification rule, the DUT/SUT does NOT use priority-based flow
      control mechanisms to manage the ingress traffic rate of the
      Classification(s) of interest, and all ingress frames are
      forwarded to the correct egress port.  A DUT may have a different
      Queueput value for each configured Classification.

      XOFF Frame: A Priority-based flow control pause frame that
      instructs the DUT to pause one or more VLAN priorities.

      XON Frame: A Priority-based flow control pause frame that
      instructs the DUT to resume transmission on one or more VLAN
      priorities.


4.  General Considerations

4.1.  Classifications

   Data Center Bridging devices SHOULD be tested with multiple
   Classifications.  Testing with a single Classification provides no
   means to test and measure a device's ability to differentiate
   forwarding behavior for different traffic classes.

4.2.  Congestion

   For devices capable of forwarding traffic at line rate, explicit
   congestion MUST be created via the test tool to benchmark queue



Player & Newman          Expires April 22, 2011                 [Page 5]


Internet-Draft              DCB Benchmarking                October 2010


   performance.  Possible methods for accomplishing this on a DUT with n
   ports include, but are not limited to:

   1.  Test full-mesh traffic patterns on (n-1) ports while using 1 port
       as a multicast transmitter with (n-1) multicast receivers.

   2.  Test full-mesh traffic patterns on (n-1) ports while generating
       partially meshed traffic between 1 and (n-1) ports.

   3.  Use partially meshed traffic patterns with x ports transmitting
       to y ports where x > y and x + y = n.

4.3.  Test Traffic

   The lock-step traffic pattern, as described in section 5.1.3 of
   [RFC2889], is specifically NOT required for DCB testing for two
   reasons:

   1.  Such patterns are not meaningful for high speed Ethernet devices
       due to the transmission clock variance allowed by the IEEE 802.3
       Ethernet specification.

   2.  Flow control mechanisms would quickly break such patterns when
       activated.

4.4.  Tester Capabilities

4.4.1.  Frame Formats

   This testing document does not mandate the use of any particular
   frame format for testing.  Any frame that can be legally forwarded by
   the DUT/SUT MAY be used provided that the test instrument can make
   the following distinctions for each frame:

   1.  The test tool MUST be able to distinguish test frames from non-
       test frames.

   2.  The test tool MUST be able to determine whether each test frame
       is forwarded to the correct egress port.

   3.  The test tool MUST be able to determine whether each received
       frame conforms or does not conform to the Conformance Vector of
       the frame's Classification Group, if applicable.








Player & Newman          Expires April 22, 2011                 [Page 6]


Internet-Draft              DCB Benchmarking                October 2010


4.4.2.  Pause Response Time

   To accurately measure the performance of a Priority-based Flow
   Control capable DUT, the test tool MUST be able to respond to PFC
   pause frames.  Additionally, the test tool MUST respond to all
   received pause frames in the time period specified in the IEEE
   802.1Qbb specification.


5.  Test Setup

   This document extends the general test setup described in section 3
   of [RFC2889] and section 6 of [RFC2544] to the benchmarking of Data
   Center Ethernet switching devices.  [RFC2889] and [RFC2544] describe
   benchmarking methodologies for networking devices that intentionally
   drop frames at their performance limits.  In DCB networks, the DUT
   will transmit PFC Pause frames as a Congestion Management method to
   throttle network endpoints, thus minimizing the probability of frame
   loss in the network.

5.1.  Test Traffic

5.1.1.  Traffic Classification

   Since DCB devices are expected to support multiple traffic
   Classifications, it is RECOMMENDED to benchmark DCB devices with
   multiple Classification Groups.

5.1.2.  Trial Duration

   The RECOMMENDED trial duration is 300 seconds.  However other
   durations MAY be used.  Additionally, a running trial MAY be aborted
   once the test tool determines that the currently running trial has
   failed, e.g.  QoS bounds exceeded, packet loss detected on a lossless
   queue, etc.

5.1.3.  Frame Measurements

   Packet Conformance MUST be determined for all test frames on a per
   frame basis.  The method specified for measuring Latency in
   [RFC2544], e.g. measuring the latency of a single test frame in a
   traffic flow, is unsuitable for DCB benchmarking.

5.1.3.1.  Forwarding Delay and Latency

   Multiple methods exist for measuring the time it takes a test frame
   to be forwarded by a DUT.  However, both of the methods discussed in
   [RFC1242] are unsuitable for testing DCB devices, as many DCB devices



Player & Newman          Expires April 22, 2011                 [Page 7]


Internet-Draft              DCB Benchmarking                October 2010


   alternate between both "store and forward" and "bit forwarding"
   behavior depending upon their queue congestion.  Hence, the only
   RECOMMENDED method for measuring the time it takes a DUT to forward a
   test frame is "Forwarding Delay" as described in [RFC4689].

5.1.4.  Frame Sizes

5.1.4.1.  Ethernet

   The recommended frame sizes for Ethernet testing are 64, 128, 256,
   512, 1024, 1280, 1518, 4096, 8192, and 9216 as per [RFC5180].  Note
   that these frame sizes include the Ethernet CRC and VLAN header.

5.1.4.1.1.  Fiber Channel over Ethernet

   FCoE test traffic introduces a number of frame size constraints that
   make the default frame sizes specified in [RFC5180] unusable:

   1.  FCoE frames contain an encapsulated Fiber Channel frame.  Due to
       the method of encapsulation used, all FCoE frames MUST be a
       multiple of 4 bytes.  See [RFC3643].

   2.  Test tools may need to include a test payload in addition to the
       encapsulated Fiber Channel frame to meet the requirements
       specified in Section 4.4.1.

   3.  The maximum supported frame size for FCoE is 2176 bytes.

   Due to these constraints, the recommended frame sizes for FCoE
   testing are 128, 256, 512, 1024, 1280, 1520, 2176, and the smallest
   FCoE frame size supported by the test tool.  Note that these frame
   sizes include both the Ethernet CRC and VLAN header.

5.1.5.  Burst Sizes

   As per [RFC2285], the burst size specifies the number of test frames
   in a burst.  To simulate bursty traffic, the test tool MAY send a
   burst of test traffic with the minimum, legal Inter-Frame Gap (IFG)
   between frames in the burst followed by a larger Inter-Burst Gap
   (IBG) between sequential bursts.  Note that burst sizes are only
   applicable to test traffic when the Offered Load of the test ports is
   less than the Maximum Offered Load (MOL) of those ports.
   Additionally, a burst size of 1 specifies a constant load, e.g. non-
   bursty traffic.







Player & Newman          Expires April 22, 2011                 [Page 8]


Internet-Draft              DCB Benchmarking                October 2010


6.  Benchmarking Tests

6.1.  Pause Response Time

6.1.1.  Objective

   To determine the amount of time required for the DUT to respond to
   priority-based flow control pause frames.

6.1.2.  Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Each Classification Group MUST be listed.  For each classification
      group, the following parameters MUST be specified:

         Codepoint - For DCB tests, the codepoint is the VLAN priority.

         Frame Size - The frame size includes both the CRC and VLAN
         header.  See Section 5.1.4 for recommended frame sizes.

         Burst Size - The burst size specifies the number of frames
         transmitted with the minimum legal IFG before pausing.  See
         Section 5.1.5.

         Intended Vector - The intended vector SHOULD specify the
         intended rate of test traffic specified as a percentage of port
         load.

         Traffic Pattern - The traffic distribution and traffic
         orientation used for this Classification.

         Conformance Vector - The conformance vector is optional, but
         MUST be defined if used.

      Priority-based Flow Control - PFC mechanisms MUST be enabled.

      Background Traffic - Background traffic MAY be present.

      PFC Pause Parameters:

         Queue(s) - A list of one or more VLAN priorities the test tool
         should attempt to pause.

         Pause Value - The quanta value to use in the XOFF frame(s).





Player & Newman          Expires April 22, 2011                 [Page 9]


Internet-Draft              DCB Benchmarking                October 2010


         XON Delay - The amount of time to pause the DUT before sending
         a XON frame.  Note that if the XON Delay is larger than the
         Pause Value, the test tool MUST send multiple XOFF frames to
         ensure that the DUT remains paused until the XON frame is
         transmitted.

6.1.3.  Procedure

   The test tool SHOULD generate test traffic for at least 30 seconds
   before sending any XOFF frame in order for the DUT to reach a steady-
   state forwarding condition.  The test tool then transmits one or more
   XOFF frames on one or more ports.  Each XOFF frame SHOULD instruct
   the DUT to pause one or more of the Classification Groups currently
   being forwarded by the DUT.  The test tool MAY optionally send a XON
   frame to instruct the DUT to resume transmission.

6.1.4.  Measurements

   The following measurements MUST be reported for each test port and
   codepoint involved in the test.

      Offered Load - the Offered Load from the DUT in N-octet frames per
      second or bits per second.  Note: The Offered Load from the DUT
      may be insufficient to accurately measure the DUT's Pause Response
      Time.  This condition SHOULD be noted in the results.

      The total number of PFC frames transmitted to the DUT by the test
      tool.

      The following values SHOULD be reported in either quanta OR
      seconds:

         Pause Response Time - The time between the transmit time of the
         last bit of the pause frame and the receive time of the first
         bit of the last codepoint matching test frame forwarded by the
         DUT before the DUT is observed to pause the intended queue.

         Intended Pause Time - The total time the test tool instructed
         the DUT to pause.

         Observed Pause Time - The actual time the DUT was observed to
         pause.

         XON Response Time - The time between the transmit time of the
         last bit of the XON frame and the receive time of the first bit
         of the first unpaused test packet from the DUT.





Player & Newman          Expires April 22, 2011                [Page 10]


Internet-Draft              DCB Benchmarking                October 2010


6.1.5.  Reporting Format

   TBD

6.2.  Queueput

6.2.1.  Objective

   To determine the Queueput for one or more Traffic Classifications of
   a DUT using priority flow control.

6.2.2.  Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Each Classification Group MUST be listed.  For each classification
      group, the following parameters MUST be specified:

         Codepoint - For DCB tests, the codepoint is the VLAN priority.

         Frame Size - The frame size includes both the CRC and VLAN
         header.  See Section 5.1.4 for recommended frame sizes.

         Burst Size - The burst size specifies the number of frames
         transmitted with the minimum legal IFG before pausing.  See
         Section 5.1.5.

         Intended Vector - The intended vector SHOULD specify the
         intended rate of test traffic specified as a percentage of port
         load.

         Traffic Pattern - The traffic distribution and traffic
         orientation used for this Classification.

         Conformance Vector - The conformance vector is optional, but
         MUST be defined if used.

      Priority-based Flow Control - PFC mechanisms MUST be enabled.

      Background Traffic - Background traffic MAY be present.

6.2.3.  Procedure

   A search algorithm is used to determine the Queueput for each
   Classification Group.  If Queue Congestion is detected for a
   Classification Group during a trial, then the Intended Vector for the
   Classification Group MUST be reduced for the subsequent trial.  If a



Player & Newman          Expires April 22, 2011                [Page 11]


Internet-Draft              DCB Benchmarking                October 2010


   Conformance Vector is specified for the test and Non-conformant
   frames are received during a trial, then the Intended Vector SHOULD
   be reduced for the subsequent trial.  The algorithm MUST adjust the
   Intended Vector for each Classification Group.  The search algorithms
   for each Classification Group MAY be run in parallel.  The test
   continues until all Classification Groups in the test have converged
   on a discrete Queueput value.

6.2.4.  Measurements

   The Queueput for each Classification MUST be reported in either
   N-octet frames per second or bits per second.

   If a Conformance Vector is specified for a Classification Group, any
   Non-conformant frames MUST be reported.

   The number of PFC pause frames transmitted by the DUT for each code-
   point in the Codepoint Set MUST be reported for each test port.

   The total pause time observed by the tester for each code-point in
   the Codepoint Set MUST be reported for each test port.

   Any frame loss observed for test traffic using PFC enabled codepoints
   MUST be reported.  Any frame loss observed for test traffic using
   non-PFC enabled codepoints on uncongested egress ports SHOULD be
   reported, as that indicates the DUT is performing Head of Line
   Blocking (HOLB).

6.2.5.  Reporting Format

   TBD

6.3.  Maximum Forwarding Rate

6.3.1.  Objective

   To determine the maximum forwarding rate of one or more PFC queues on
   a PFC capable DUT.

6.3.2.  Setup Parameters

   Maximum Forwarding Rate is conceptually similar to the measurement in
   [RFC2285] but works on a per-Classification basis in a DCB context.
   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Each Classification Group MUST be listed.  For each classification
      group, the following parameters MUST be specified:



Player & Newman          Expires April 22, 2011                [Page 12]


Internet-Draft              DCB Benchmarking                October 2010


         Codepoint - For DCB tests, the codepoint is the VLAN priority.

         Frame Size - The frame size includes both the CRC and VLAN
         header.  See Section 5.1.4 for recommended frame sizes.

         Burst Size - The burst size specifies the number of frames
         transmitted with the minimum legal IFG before pausing.  See
         Section 5.1.5.

         Intended Vector - The intended vector includes the intended
         rate of test traffic specified as a percentage of port load.

         Traffic Pattern - The traffic distribution and traffic
         orientation used for this Classification.

         Conformance Vector - The conformance vector is optional, but
         MUST be defined if used.

      Priority-based Flow Control - PFC mechanisms SHOULD be disabled.

      Background Traffic - Background traffic MAY be present.

6.3.3.  Procedure

   The tester should iterate across all configured permutations of frame
   size, burst size, and Intended Vector for all Classification Groups.

6.3.4.  Measurements

   The forwarding rate of each Classification Group MUST be reported as
   the number of N-octet test frames per second the DUT correctly
   forwards to the proper egress port.

   The maximum forwarding rate for each Classification Group MUST be
   reported as the highest recorded forwarding rate from the set of all
   iterations.

   Both the Intended and Offered Vector of each Classification Group
   MUST be reported.

   If a Conformance Vector is specified for a Classification Group, any
   Non-conformant frames MUST be reported.

   The number of PFC pause frames transmitted by the DUT for each code-
   point in the Codepoint Set MUST be reported.

   The total pause time observed by the tester for each code-point in
   the Codepoint Set MUST be reported.



Player & Newman          Expires April 22, 2011                [Page 13]


Internet-Draft              DCB Benchmarking                October 2010


6.3.5.  Reporting Format

   TBD

6.4.  Back-off

6.4.1.  Objective

   To determine the delta between the maximum forwarding rate of a DUT
   and the point where the DUT ceases to use PFC to manage priority
   queues.

6.4.2.  Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations.

      Each Classification Group MUST be listed.  For each classification
      group, the following parameters MUST be specified:

         Codepoint - For DCB tests, the codepoint is the VLAN priority.

         Frame Size - The frame size includes both the CRC and VLAN
         header.  See Section 5.1.4 for recommended frame sizes.

         Burst Size - The burst size specifies the number of frames
         transmitted with the minimum legal IFG before pausing.  See
         Section 5.1.5.

         Intended Vector - The intended vector includes the intended
         rate of test traffic specified as a percentage of port load.

         Traffic Pattern - The traffic distribution and traffic
         orientation used for this Classification.

         Conformance Vector - The conformance vector is optional, but
         MUST be defined if used.

      Priority-based Flow Control - PFC mechanisms MUST be enabled.

      Backoff method - The recommended backoff method is to reduce the
      aggregate traffic load by a fixed amount while still maintaining a
      fixed load ratio between all Classification Groups.








Player & Newman          Expires April 22, 2011                [Page 14]


Internet-Draft              DCB Benchmarking                October 2010


6.4.3.  Procedure

   The initial trial SHOULD begin with an Intended Load equal to or
   greater than the Maximum Forwarding Rate of the DUT/SUT.  For each
   subsequent trial, the aggregate load is reduced until the DUT is
   observed to complete a trial without activating any Congestion
   Management methods.

6.4.4.  Measurements

   The Intended and Offered Vector for each Classification Group MUST be
   reported.

   If a Conformance Vector is specified for a Classification Group, any
   Non-conformant frames MUST be reported.

   The number of PFC pause frames transmitted by the DUT for each code-
   point in the Codepoint Set MUST be reported.

   The total pause time observed by the tester for each code-point in
   the Codepoint Set MUST be reported.

   Any frame loss observed for test traffic using PFC enabled codepoints
   MUST be reported.  Any frame loss observed for test traffic using
   non-PFC enabled codepoints on uncongested egress ports SHOULD be
   reported, as that indicates the DUT is performing Head of Line
   Blocking (HOLB).

6.4.5.  Reporting Format

   TBD

6.5.  Back-to-Back

6.5.1.  Objective

   To determine the maximum duration a DUT can forward test traffic with
   minimum Inter-Frame Gap on one or more PFC queues without using
   Congestion Management.

6.5.2.  Setup Parameters

   The following parameters MUST be defined.  Each variable is
   configured with the following considerations

      Each Classification Group MUST be listed.  For each classification
      group, the following parameters MUST be specified:




Player & Newman          Expires April 22, 2011                [Page 15]


Internet-Draft              DCB Benchmarking                October 2010


         Codepoint - For DCB tests, the codepoint is the VLAN priority.

         Frame Size - The frame size includes both the CRC and VLAN
         header.  See Section 5.1.4 for recommended frame sizes.

         Intended Vector - The intended vector includes the intended
         rate of test traffic specified as a percentage of port load.

         Traffic Pattern - The traffic distribution and traffic
         orientation used for this Classification.

         Conformance Vector - The conformance vector is optional, but
         MUST be defined if used.

      Priority-based Flow Control - PFC mechanisms MUST be enabled.

      The sum of all Intended Vectors on a transmitting port SHOULD
      equal the Maximum Offered Load (MOL) of that port.

6.5.3.  Procedure

   A search algorithm is used to determine the maximum duration in
   seconds for which the configured Classification Profile can be
   forwarded by the DUT without active Congestion Management.  If
   Congestion Management is detected during an iteration, then the
   duration MUST be reduced for the next iteration.

6.5.4.  Measurements

   The Intended and Offered Vector for each Classification Group MUST be
   reported.

   If a Conformance Vector is specified for a Classification Group, any
   Non-conformant frames MUST be reported.

   The number of PFC pause frames transmitted by the DUT for each code-
   point in the Codepoint Set MUST be reported.

   The total pause time observed by the tester for each code-point in
   the Codepoint Set MUST be reported.

   Any frame loss observed for test traffic using PFC enabled codepoints
   MUST be reported.  Any frame loss observed for test traffic using
   non-PFC enabled codepoints on uncongested egress ports SHOULD be
   reported, as that indicates the DUT is performing Head of Line
   Blocking (HOLB).





Player & Newman          Expires April 22, 2011                [Page 16]


Internet-Draft              DCB Benchmarking                October 2010


6.5.5.  Reporting Format

   TBD


7.  Security Considerations

   Benchmarking activities as described in this memo are limited to
   technology characterization using controlled stimuli in a laboratory
   environment, with dedicated address space and the constraints
   specified in the sections above.

   The benchmarking network topology will be an independent test setup
   and MUST NOT be connected to devices that may forward the test
   traffic into a production network, or misroute traffic to the test
   management network.

   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 Consdierations

   Testers SHOULD use network addresses assigned by IANA for the purpose
   of testing networks.


9.  Normative References

   [RFC1242]  Bradner, S., "Benchmarking terminology for network
              interconnection devices", RFC 1242, July 1991.

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

   [RFC2285]  Mandeville, R., "Benchmarking Terminology for LAN
              Switching Devices", RFC 2285, February 1998.

   [RFC2544]  Bradner, S. and J. McQuaid, "Benchmarking Methodology for
              Network Interconnect Devices", RFC 2544, March 1999.

   [RFC2889]  Mandeville, R. and J. Perser, "Benchmarking Methodology
              for LAN Switching Devices", RFC 2889, August 2000.



Player & Newman          Expires April 22, 2011                [Page 17]


Internet-Draft              DCB Benchmarking                October 2010


   [RFC3643]  Weber, R., Rajagopal, M., Travostino, F., O'Donnell, M.,
              Monia, C., and M. Merhar, "Fibre Channel (FC) Frame
              Encapsulation", RFC 3643, December 2003.

   [RFC4689]  Poretsky, S., Perser, J., Erramilli, S., and S. Khurana,
              "Terminology for Benchmarking Network-layer Traffic
              Control Mechanisms", RFC 4689, October 2006.

   [RFC5180]  Popoviciu, C., Hamza, A., Van de Velde, G., and D.
              Dugatkin, "IPv6 Benchmarking Methodology for Network
              Interconnect Devices", RFC 5180, May 2008.


Appendix A.  Acknowledgements


Authors' Addresses

   Timmons C. Player
   Spirent Communications

   Email: timmons.player@spirent.com


   David Newman
   Network Test

   Email: dnewman@networktest.com























Player & Newman          Expires April 22, 2011                [Page 18]