    Network Working Group                                         B. Hickman
    Request for Comments: 3511                        Spirent Communications
    Category: Informational                                        D. Newman
                                                                Network Test
                                                                 S. Tadjudin
                                                      Spirent Communications
                                                                   T. Martin
                                                         GVNW Consulting Inc
                                                                  April 2003

               Benchmarking Methodology for Firewall Performance

    Status of this Memo

       This memo provides information for the Internet community.  It does
       not specify an Internet standard of any kind.  Distribution of this
       memo is unlimited.

    Copyright Notice

       Copyright (C) The Internet Society (2003).  All Rights Reserved.

    Abstract

       This document discusses and defines a number of tests that may be
       used to describe the performance characteristics of firewalls.  In
       addition to defining the tests, this document also describes specific
       formats for reporting the results of the tests.

       This document is a product of the Benchmarking Methodology Working
       Group (BMWG) of the Internet Engineering Task Force (IETF).

    Table of Contents

       1. Introduction . . . . . . . . . . . . . . . . . . . . . . . .  2
       2. Requirements . . . . . . . . . . . . . . . . . . . . . . . .  2
       3. Scope  . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
       4. Test setup . . . . . . . . . . . . . . . . . . . . . . . . .  3
          4.1 Test Considerations. . . . . . . . . . . . . . . . . . .  4
          4.2 Virtual Client/Servers . . . . . . . . . . . . . . . . .  4
          4.3 Test Traffic Requirements. . . . . . . . . . . . . . . .  5
          4.4 DUT/SUT Traffic Flows. . . . . . . . . . . . . . . . . .  5
          4.5 Multiple Client/Server Testing . . . . . . . . . . . . .  5
          4.6 Network Address Translation (NAT). . . . . . . . . . . .  6
          4.7 Rule Sets. . . . . . . . . . . . . . . . . . . . . . . .  6
          4.8 Web Caching. . . . . . . . . . . . . . . . . . . . . . .  6
          4.9 Authentication . . . . . . . . . . . . . . . . . . . . .  7

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          4.10 TCP Stack Considerations. . . . . . . . . . . . . . . .  7
       5. Benchmarking Tests . . . . . . . . . . . . . . . . . . . . .  7
          5.1 IP throughput. . . . . . . . . . . . . . . . . . . . . .  7
          5.2 Concurrent TCP Connection Capacity . . . . . . . . . . .  9
          5.3 Maximum TCP Connection Establishment Rate. . . . . . . . 12
          5.4 Maximum TCP Connection Tear Down Rate. . . . . . . . . . 14
          5.5 Denial Of Service Handling . . . . . . . . . . . . . . . 16
          5.6 HTTP Transfer Rate . . . . . . . . . . . . . . . . . . . 18
          5.7 Maximum HTTP Transaction Rate. . . . . . . . . . . . . . 21
          5.8 Illegal Traffic Handling . . . . . . . . . . . . . . . . 23
          5.9 IP Fragmentation Handling. . . . . . . . . . . . . . . . 24
          5.10 Latency . . . . . . . . . . . . . . . . . . . . . . . . 26
       6. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
          6.1 Normative References . . . . . . . . . . . . . . . . . . 29
          6.2 Informative References . . . . . . . . . . . . . . . . . 30
       7. Security Consideration . . . . . . . . . . . . . . . . . . . 30
       Appendix A - HyperText Transfer Protocol (HTTP) . . . . . . . . 31
       Appendix B - Connection Establishment Time Measurements . . . . 31
       Appendix C - Connection Tear Down Time Measurements . . . . . . 32
       Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . 33
       Full Copyright Statement  . . . . . . . . . . . . . . . . . . . 34

    1. Introduction

       This document provides methodologies for the performance benchmarking
       of firewalls.  It covers four areas: forwarding, connection, latency
       and filtering.  In addition to defining tests, this document also
       describes specific formats for reporting test results.

       A previous document, "Benchmarking Terminology for Firewall
       Performance" [1], defines many of the terms that are used in this
       document.  The terminology document SHOULD be consulted before
       attempting to make use of this document.

    2. Requirements

       In this document, the words that are used to define the significance
       of each particular requirement are capitalized.  These words are:

       *  "MUST" This word, or the words "REQUIRED" and "SHALL" mean that
          the item is an absolute requirement of the specification.

       *  "SHOULD" This word or the adjective "RECOMMENDED" means that there
          may exist valid reasons in particular circumstances to ignore this
          item, but the full implications should be understood and the case
          carefully weighed before choosing a different course.

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       *  "MAY" This word or the adjective "OPTIONAL" means that this item
          is truly optional.  One vendor may choose to include the item
          because a particular marketplace requires it or because it
          enhances the product, for example; another vendor may omit the
          same item.

       An implementation is not compliant if it fails to satisfy one or more
       of the MUST requirements.  An implementation that satisfies all the
       MUST and all the SHOULD requirements is said to be "unconditionally
       compliant"; one that satisfies all the MUST requirements but not all
       the SHOULD requirements is said to be "conditionally compliant".

    3. Scope

       Firewalls can control access between networks.  Usually, a firewall
       protects a private network from public or shared network(s) to which
       it is connected.  A firewall can be as simple as a single device that
       filters packets or as complex as a group of devices that combine
       packet filtering and application-level proxy and network translation
       services.  This document focuses on benchmarking firewall
       performance, wherever possible, independent of implementation.

    4. Test Setup

       Test configurations defined in this document will be confined to
       dual-homed and tri-homed as shown in figure 1 and figure 2
       respectively.

       Firewalls employing dual-homed configurations connect two networks.
       One interface of the firewall is attached to the unprotected network
       [1], typically the public network (Internet).  The other interface is
       connected to the protected network [1], typically the internal LAN.

       In the case of dual-homed configurations, servers which are made
       accessible to the public (Unprotected) network are attached to the
       private (Protected) network.

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       +----------+                                       +----------+
       |          |    |       +----------+        |      |          |
       | Servers/ |----|       |          |        |------| Servers/ |
       | Clients  |    |       |          |        |      | Clients  |
       |          |    |-------|  DUT/SUT |--------|      |          |
       +----------+    |       |          |        |      +----------+
            Protected  |       +----------+        | Unprotected
             Network   |                           |   Network
                           Figure 1 (Dual-Homed)

       Tri-homed [1] configurations employ a third segment called a
       Demilitarized Zone (DMZ).  With tri-homed configurations, servers
       accessible to the public network are attached to the DMZ.  Tri-Homed
       configurations offer additional security by separating server(s)
       accessible to the public network from internal hosts.

       +----------+                                       +----------+
       |          |    |       +----------+        |      |          |
       | Clients  |----|       |          |        |------| Servers/ |
       |          |    |       |          |        |      | Clients  |
       +----------+    |-------|  DUT/SUT |--------|      |          |
                       |       |          |        |      +----------+
                       |       +----------+        |
             Protected |            |              | Unprotected
              Network               |                   Network
                                    |
                              -----------------
                                        |    DMZ
                                        |
                                        |
                                 +-----------+
                                 |           |
                                 | Servers   |
                                 |           |
                                 +-----------+

                              Figure 2 (Tri-Homed)

    4.1 Test Considerations

    4.2 Virtual Clients/Servers

       Since firewall testing may involve data sources which emulate
       multiple users or hosts, the methodology uses the terms virtual
       clients/servers.  For these firewall tests, virtual clients/servers
       specify application layer entities which may not be associated with a
       unique physical interface.  For example, four virtual clients may

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       originate from the same data source [1].  The test report MUST
       indicate the number of virtual clients and virtual servers
       participating in the test.

    4.3 Test Traffic Requirements

       While the function of a firewall is to enforce access control
       policies, the criteria by which those policies are defined vary
       depending on the implementation.  Firewalls may use network layer,
       transport layer or, in many cases, application-layer criteria to make
       access-control decisions.

       For the purposes of benchmarking firewall performance, this document
       references HTTP 1.1 or higher as the application layer entity.  The
       methodologies MAY be used as a template for benchmarking with other
       applications.  Since testing may involve proxy based DUT/SUTs, HTTP
       version considerations are discussed in appendix A.

    4.4 DUT/SUT Traffic Flows

       Since the number of interfaces are not fixed, the traffic flows will
       be dependent upon the configuration used in benchmarking the DUT/SUT.
       Note that the term "traffic flows" is associated with client-to-
       server requests.

       For Dual-Homed configurations, there are two unique traffic flows:

          Client         Server
          ------         ------
          Protected   -> Unprotected
          Unprotected -> Protected

       For Tri-Homed configurations, there are three unique traffic flows:

          Client         Server
          ------         ------
          Protected ->   Unprotected
          Protected ->   DMZ
          Unprotected -> DMZ

    4.5 Multiple Client/Server Testing

       One or more clients may target multiple servers for a given
       application.  Each virtual client MUST initiate connections in a
       round-robin fashion.  For example, if the test consisted of six
       virtual clients targeting three servers, the pattern would be as
       follows:

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          Client          Target Server (In order of request)
          #1              1     2     3     1...
          #2              2     3     1     2...
          #3              3     1     2     3...
          #4              1     2     3     1...
          #5              2     3     1     2...
          #6              3     1     2     3...

    4.6 Network Address Translation (NAT)

       Many firewalls implement network address translation (NAT) [1], a
       function which translates private internet addresses to public
       internet addresses.  This involves additional processing on the part
       of the DUT/SUT and may impact performance.  Therefore, tests SHOULD
       be ran with NAT disabled and NAT enabled to determine the performance
       differential, if any.  The test report MUST indicate whether NAT was
       enabled or disabled.

    4.7 Rule Sets

       Rule sets [1] are a collection of access control policies that
       determine which packets the DUT/SUT will forward and which it will
       reject [1].  Since criteria by which these access control policies
       may be defined will vary depending on the capabilities of the
       DUT/SUT, the following is limited to providing guidelines for
       configuring rule sets when benchmarking the performance of the
       DUT/SUT.

       It is RECOMMENDED that a rule be entered for each host (Virtual
       client).  In addition, testing SHOULD be performed using different
       size rule sets to determine its impact on the performance of the
       DUT/SUT.  Rule sets MUST be configured in a manner, such that, rules
       associated with actual test traffic are configured at the end of the
       rule set and not at the beginning.

       The DUT/SUT SHOULD be configured to deny access to all traffic which
       was not previously defined in the rule set.  The test report SHOULD
       include the DUT/SUT configured rule set(s).

    4.8 Web Caching

       Some firewalls include caching agents to reduce network load.  When
       making a request through a caching agent, the caching agent attempts
       to service the response from its internal memory.  The cache itself
       saves responses it receives, such as responses for HTTP GET requests.
       Testing SHOULD be performed with any caching agents on the DUT/SUT
       disabled.

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    4.9 Authentication

       Access control may involve authentication processes such as user,
       client or session authentication.  Authentication is usually
       performed by devices external to the firewall itself, such as an
       authentication server(s) and may add to the latency of the system.
       Any authentication processes MUST be included as part of connection
       setup process.

    4.10 TCP Stack Considerations

       Some test instruments allow configuration of one or more TCP stack
       parameters, thereby influencing the traffic flows which will be
       offered and impacting performance measurements.  While this document
       does not attempt to specify which TCP parameters should be
       configurable, any such TCP parameter(s) MUST be noted in the test
       report.  In addition, when comparing multiple DUT/SUTs, the same TCP
       parameters MUST be used.

    5. Benchmarking Tests

    5.1 IP Throughput

    5.1.1 Objective

       To determine the throughput of network-layer data traversing the
       DUT/SUT, as defined in RFC 1242 [3].  Note that while RFC 1242 uses
       the term frames, which is associated with the link layer, the
       procedure uses the term packets, since it is referencing the network
       layer.

    5.1.2 Setup Parameters

       The following parameters MUST be defined:

          Packet size - Number of bytes in the IP packet, exclusive of any
          link layer header or checksums.

          Test Duration - Duration of the test, expressed in seconds.

    5.1.3 Procedure

       The test instrument MUST offer unicast IP packets to the DUT/SUT at a
       constant rate.  The test MAY consist of either bi-directional or
       unidirectional traffic; for example, an emulated client may offer a
       unicast stream of packets to an emulated server, or the test
       instrument may simulate a client/server exchange by offering
       bidirectional traffic.

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       This test will employ an iterative search algorithm.  Each iteration
       will involve the test instrument varying the intended load until the
       maximum rate, at which no packet loss occurs, is found.  Since
       backpressure mechanisms may be employed, resulting in the intended
       load and offered load being different, the test SHOULD be performed
       in either a packet based or time based manner as described in RFC
       2889 [5].  As with RFC 1242, the term packet is used in place of
       frame.  The duration of the test portion of each trial MUST be at
       least 30 seconds.

       It is RECOMMENDED to perform the throughput measurements with
       different packet sizes.  When testing with different packet sizes the
       DUT/SUT configuration MUST remain the same.

    5.1.4 Measurement

    5.1.4.1 Network Layer

       Throughput:
          Maximum offered load, expressed in either bits per second or
          packets per second, at which no packet loss is detected.  The bits
          to be counted are in the IP packet (header plus payload); other
          fields, such as link-layer headers and trailers, MUST NOT be
          included in the measurement.

       Forwarding Rate:
          Forwarding rate, expressed in either bits per second or packets
          per second, the device is observed to successfully forward to the
          correct destination interface in response to a specified offered
          load.  The bits to be counted are in the IP packet (header plus
          payload); other fields, such as link-layer headers and trailers,
          MUST NOT be included in the measurement.

    5.1.5 Reporting Format

       The test report MUST note the packet size(s), test duration,
       throughput and forwarding rate. In addition, the test report MUST
       conform to the reporting requirements set in section 4, Test Setup.
       If the test involved offering packets which target more than one
       segment (Protected, Unprotected or DMZ), the report MUST identify the
       results as an aggregate throughput measurement.

       The throughput results SHOULD be reported in the format of a table
       with a row for each of the tested packet sizes.  There SHOULD be
       columns for the packet size, the intended load, the offered load,
       resultant throughput and forwarding rate for each test.

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       The intermediate results of the search algorithm MAY be saved in log
       file which includes the packet size, test duration and for each
       iteration:

          - Step Iteration
          - Pass/Fail Status
          - Total packets offered
          - Total packets forwarded
          - Intended load
          - Offered load (If applicable)
          - Forwarding rate

    5.2 Concurrent TCP Connection Capacity

    5.2.1 Objective

       To determine the maximum number of concurrent TCP connections
       supported through or with the DUT/SUT, as defined in RFC 2647 [1].
       This test is intended to find the maximum number of entries the
       DUT/SUT can store in its connection table.

    5.2.2 Setup Parameters

       The following parameters MUST be defined for all tests:

    5.2.2.1 Transport-Layer Setup Parameters

       Connection Attempt Rate:
          The aggregate rate, expressed in connections per second, at which
          TCP connection requests are attempted.  The rate SHOULD be set at
          or lower than the maximum rate at which the DUT/SUT can accept
          connection requests.

       Aging Time:
          The time, expressed in seconds, the DUT/SUT will keep a connection
          in its connection table after receiving a TCP FIN or RST packet.

    5.2.2.2 Application-Layer Setup Parameters

       Validation Method:
          HTTP 1.1 or higher MUST be used for this test for both clients and
          servers.  The client and server MUST use the same HTTP version.

       Object Size:
          Defines the number of bytes, excluding any bytes associated with
          the HTTP header, to be transferred in response to an HTTP 1.1 or
          higher GET request.

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    5.2.3 Procedure

       This test will employ an iterative search algorithm to determine the
       maximum number of concurrent TCP connections supported through or
       with the DUT/SUT.

       For each iteration, the aggregate number of concurrent TCP
       connections attempted by the virtual client(s) will be varied.  The
       destination address will be that of the server or that of the NAT
       proxy.  The aggregate rate will be defined by connection attempt
       rate, and will be attempted in a round-robin fashion (See 4.5).

       To validate all connections, the virtual client(s) MUST request an
       object using an HTTP 1.1 or higher GET request.  The requests MUST be
       initiated on each connection after all of the TCP connections have
       been established.

       When testing proxy-based DUT/SUTs, the virtual client(s) MUST request
       two objects using HTTP 1.1 or higher GET requests.  The first GET
       request is required for connection time establishment [1]
       measurements as specified in appendix B.  The second request is used
       for validation as previously mentioned.  When comparing proxy and
       non-proxy based DUT/SUTs, the test MUST be performed in the same
       manner.

       Between each iteration, it is RECOMMENDED that the test instrument
       issue a TCP RST referencing each connection attempted for the
       previous iteration, regardless of whether or not the connection
       attempt was successful.  The test instrument will wait for aging time
       before continuing to the next iteration.

    5.2.4 Measurements

    5.2.4.1 Application-Layer measurements

       Number of objects requested

       Number of objects returned

    5.2.4.2 Transport-Layer measurements

       Maximum concurrent connections:
          Total number of TCP connections open for the last successful
          iteration performed in the search algorithm.

       Minimum connection establishment time:
          Lowest TCP connection establishment time measured, as defined in
          appendix B.

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       Maximum connection establishment time:
          Highest TCP connection establishment time measured, as defined in
          appendix B.

       Average connection establishment time:
          The mean of all measurements of connection establishment times.

       Aggregate connection establishment time:
          The total of all measurements of connection establishment times.

    5.2.5 Reporting Format

       The test report MUST conform to the reporting requirements set in
       section 4, Test Setup.

    5.2.5.1 Application-Layer Reporting:

       The test report MUST note the object size, number of completed
       requests and number of completed responses.

       The intermediate results of the search algorithm MAY be reported in a
       tabular format with a column for each iteration.  There SHOULD be
       rows for the number of requests attempted, number and percentage
       requests completed, number of responses attempted, number and
       percentage of responses completed.  The table MAY be combined with
       the transport-layer reporting, provided that the table identify this
       as an application layer measurement.

       Version information:
          The test report MUST note the version of HTTP client(s) and
          server(s).

    5.2.5.2 Transport-Layer Reporting:

       The test report MUST note the connection attempt rate, aging time,
       minimum TCP connection establishment time, maximum TCP connection
       establishment time, average connection establishment time, aggregate
       connection establishment time and maximum concurrent connections
       measured.

       The intermediate results of the search algorithm MAY be reported in
       the format of a table with a column for each iteration.  There SHOULD
       be rows for the total number of TCP connections attempted, number and
       percentage of TCP connections completed, minimum TCP connection
       establishment time, maximum TCP connection establishment time,
       average connection establishment time and the aggregate connection
       establishment time.

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    5.3 Maximum TCP Connection Establishment Rate

    5.3.1 Objective

       To determine the maximum TCP connection establishment rate through or
       with the DUT/SUT, as defined by RFC 2647 [1].  This test is intended
       to find the maximum rate the DUT/SUT can update its connection table.

    5.3.2 Setup Parameters

       The following parameters MUST be defined for all tests:

    5.3.2.1 Transport-Layer Setup Parameters

       Number of Connections:
          Defines the aggregate number of TCP connections that must be
          established.

       Aging Time:
          The time, expressed in seconds, the DUT/SUT will keep a connection
          in it's state table after receiving a TCP FIN or RST packet.

    5.3.2.2 Application-Layer Setup Parameters

       Validation Method:
          HTTP 1.1 or higher MUST be used for this test for both clients and
          servers.  The client and server MUST use the same HTTP version.

       Object Size:
          Defines the number of bytes, excluding any bytes associated with
          the HTTP header, to be transferred in response to an HTTP 1.1 or
          higher GET request.

    5.3.3 Procedure

       This test will employ an iterative search algorithm to determine the
       maximum rate at which the DUT/SUT can accept TCP connection requests.

       For each iteration, the aggregate rate at which TCP connection
       requests are attempted by the virtual client(s) will be varied.  The
       destination address will be that of the server or that of the NAT
       proxy.  The aggregate number of connections, defined by number of
       connections, will be attempted in a round-robin fashion (See 4.5).

       The same application-layer object transfers required for validation
       and establishment time measurements as described in the concurrent
       TCP connection capacity test MUST be performed.

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       Between each iteration, it is RECOMMENDED that the test instrument
       issue a TCP RST referencing each connection attempted for the
       previous iteration, regardless of whether or not the connection
       attempt was successful.  The test instrument will wait for aging time
       before continuing to the next iteration.

    5.3.4 Measurements

    5.3.4.1 Application-Layer measurements

       Number of objects requested

       Number of objects returned

    5.3.4.2 Transport-Layer measurements

       Highest connection rate:
          Highest rate, in connections per second, for which all connections
          successfully opened in the search algorithm.

       Minimum connection establishment time:
          Lowest TCP connection establishment time measured, as defined in
          appendix B.

       Maximum connection establishment time:
          Highest TCP connection establishment time measured, as defined in
          appendix B.

       Average connection establishment time:
          The mean of all measurements of connection establishment times.

       Aggregate connection establishment time:
          The total of all measurements of connection establishment times.

    5.3.5 Reporting Format

       The test report MUST conform to the reporting requirements set in
       section 4, Test Setup.

    5.3.5.1 Application-Layer Reporting:

       The test report MUST note object size(s), number of completed
       requests and number of completed responses.

       The intermediate results of the search algorithm MAY be reported in a
       tabular format with a column for each iteration.  There SHOULD be
       rows for the number of requests attempted, number and percentage
       requests completed, number of responses attempted, number and

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       percentage of responses completed.  The table MAY be combined with
       the transport-layer reporting, provided that the table identify this
       as an application layer measurement.

       Version information:
          The test report MUST note the version of HTTP client(s) and
          server(s).

    5.3.5.2 Transport-Layer Reporting:

       The test report MUST note the number of connections, aging time,
       minimum TCP connection establishment time, maximum TCP connection
       establishment time, average connection establishment time, aggregate
       connection establishment time and highest connection rate measured.

       The intermediate results of the search algorithm MAY be reported in
       the format of a table with a column for each iteration.  There SHOULD
       be rows for the connection attempt rate, total number of TCP
       connections attempted, total number of TCP connections completed,
       minimum TCP connection establishment time, maximum TCP connection
       establishment time, average connection establishment time and the
       aggregate connection establishment time.

    5.4 Maximum TCP Connection Tear Down Rate

    5.4.1 Objective

       To determine the maximum TCP connection tear down rate through or
       with the DUT/SUT, as defined by RFC 2647 [1].

    5.4.2 Setup Parameters

       Number of Connections:
          Defines the number of TCP connections that will be attempted to be
          torn down.

       Aging Time:
          The time, expressed in seconds, the DUT/SUT will keep a connection
          in it's state table after receiving a TCP FIN or RST packet.

       Close Method:
          Defines method for closing TCP connections.  The test MUST be
          performed with either a three-way or four-way handshake.  In a
          four-way handshake, each side sends separate FIN and ACK messages.
          In a three-way handshake, one side sends a combined FIN/ACK
          message upon receipt of a FIN.

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       Close Direction:
          Defines whether closing of connections are to be initiated from
          the client or from the server.

    5.4.3 Procedure

       This test will employ an iterative search algorithm to determine the
       maximum TCP connection tear down rate supported by the DUT/SUT.  The
       test iterates through different TCP connection tear down rates with a
       fixed number of TCP connections.

       In the case of proxy based DUT/SUTs, the DUT/SUT will itself receive
       the ACK in response to issuing a FIN packet to close its side of the
       TCP connection.  For validation purposes, the virtual client or
       server, whichever is applicable, MAY verify that the DUT/SUT received
       the final ACK by re-transmitting the final ACK.  A TCP RST should be
       received in response to the retransmitted ACK.

       Between each iteration, it is RECOMMENDED that the virtual client(s)
       or server(s), whichever is applicable, issue a TCP RST referencing
       each connection which was attempted to be torn down, regardless of
       whether or not the connection tear down attempt was successful.  The
       test will wait for aging time before continuing to the next
       iteration.

    5.4.4 Measurements

       Highest connection tear down rate:
          Highest rate, in connections per second, for which all TCP
          connections were successfully torn down in the search algorithm.

       The following tear down time [1] measurements MUST only include
       connections for which both sides of the connection were successfully
       torn down.  For example, tear down times for connections which are
       left in a FINWAIT-2 [8] state should not be included:

       Minimum connection tear down time:
          Lowest TCP connection tear down time measured as defined in
          appendix C.

       Maximum connection tear down time:
          Highest TCP connection tear down time measured as defined in
          appendix C.

       Average connection tear down time:
          The mean of all measurements of connection tear down times.

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       Aggregate connection tear down time:
          The total of all measurements of connection tear down times.

    5.4.5 Reporting Format

       The test report MUST note the number of connections, aging time,
       close method, close direction, minimum TCP connection tear down time,
       maximum TCP connection tear down time, average TCP connection tear
       down time and the aggregate TCP connection tear down time and highest
       connection tear down rate measured. In addition, the test report MUST
       conform to the reporting requirements set in section 4, Test Setup.

       The intermediate results of the search algorithm MAY be reported in
       the format of a table with a column for each iteration.  There SHOULD
       be rows for the number of TCP tear downs attempted, number and
       percentage of TCP connection tear downs completed, minimum TCP
       connection tear down time, maximum TCP connection tear down time,
       average TCP connection tear down time, aggregate TCP connection tear
       down time and validation failures, if required.

    5.5 Denial Of Service Handling

    5.5.1 Objective

       To determine the effect of a denial of service attack on a DUT/SUT
       TCP connection establishment and/or HTTP transfer rates.  The denial
       of service handling test MUST be run after obtaining baseline
       measurements from sections 5.3 and/or 5.6.

       The TCP SYN flood attack exploits TCP's three-way handshake mechanism
       by having an attacking source host generate TCP SYN packets with
       random source addresses towards a victim host, thereby consuming that
       host's resources.

    5.5.2 Setup Parameters

       Use the same setup parameters as defined in section 5.3.2 or 5.6.2,
       depending on whether testing against the baseline TCP connection
       establishment rate test or HTTP transfer rate test, respectfully.

       In addition, the following setup parameters MUST be defined:

       SYN attack rate:
          Rate, expressed in packets per second, at which the server(s) or
          NAT proxy address is targeted with TCP SYN packets.

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    5.5.3 Procedure

       Use the same procedure as defined in section 5.3.3 or 5.6.3,
       depending on whether testing against the baseline TCP connection
       establishment rate or HTTP transfer rate test, respectfully.  In
       addition, the test instrument will generate TCP SYN packets targeting
       the server(s) IP address or NAT proxy address at a rate defined by
       SYN attack rate.

       The test instrument originating the TCP SYN attack MUST be attached
       to the unprotected network.  In addition, the test instrument MUST
       not respond to the SYN/ACK packets sent by target server or NAT proxy
       in response to the SYN packet.

       Some firewalls employ mechanisms to guard against SYN attacks.  If
       such mechanisms exist on the DUT/SUT, tests SHOULD be run with these
       mechanisms enabled and disabled to determine how well the DUT/SUT can
       maintain, under such attacks, the baseline connection establishment
       rates and HTTP transfer rates determined in section 5.3 and section
       5.6, respectively.

    5.5.4 Measurements

       Perform the same measurements as defined in section 5.3.4 or 5.6.4,
       depending on whether testing against the baseline TCP connection
       establishment rate test or HTTP transfer rate, respectfully.

       In addition, the test instrument SHOULD track TCP SYN packets
       associated with the SYN attack which the DUT/SUT forwards on the
       protected or DMZ interface(s).

    5.5.5 Reporting Format

       The test SHOULD use the same reporting format as described in section
       5.3.5 or 5.6.5, depending on whether testing against the baseline TCP
       connection establishment rate test or HTTP transfer rate,
       respectfully.

       In addition, the report MUST indicate a denial of service handling
       test, SYN attack rate, number of TCP SYN attack packets transmitted
       and the number of TCP SYN attack packets forwarded by the DUT/SUT.
       The report MUST indicate whether or not the DUT has any SYN attack
       mechanisms enabled.

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    5.6 HTTP Transfer Rate

    5.6.1 Objective

       To determine the transfer rate of HTTP requested object traversing
       the DUT/SUT.

    5.6.2 Setup Parameters

       The following parameters MUST be defined for all tests:

    5.6.2.1 Transport-Layer Setup Parameters

       Number of connections:
          Defines the aggregate number of connections attempted.  The number
          SHOULD be a multiple of the number of virtual clients
          participating in the test.

       Close Method:
          Defines the method for closing TCP connections.  The test MUST be
          performed with either a three-way or four-way handshake.  In a
          four-way handshake, each side sends separate FIN and ACK messages.
          In a three-way handshake, one side sends a combined FIN/ACK
          message upon receipt of a FIN.

       Close Direction:
          Defines whether closing of connections are to be initiated from
          the client or from the server.

    5.6.2.2 Application-Layer Setup Parameters

       Session Type:
          The virtual clients/servers MUST use HTTP 1.1 or higher.  The
          client and server MUST use the same HTTP version.

       GET requests per connection:
          Defines the number of HTTP 1.1 or higher GET requests attempted
          per connection.

       Object Size:
          Defines the number of bytes, excluding any bytes associated with
          the HTTP header, to be transferred in response to an HTTP 1.1 or
          higher GET request.

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    5.6.3 Procedure

       Each HTTP 1.1 or higher virtual client will request one or more
       objects from an HTTP 1.1 or higher server using one or more HTTP GET
       requests over each connection.  The aggregate number of connections
       attempted, defined by number of connections, MUST be evenly divided
       among all of the participating virtual clients.

       If the virtual client(s) make multiple HTTP GET requests per
       connection, it MUST request the same object size for each GET
       request.  Multiple iterations of this test may be run with objects of
       different sizes.

    5.6.4 Measurements

    5.6.4.1 Application-Layer measurements

       Average Transfer Rate :
          The average transfer rate of the DUT/SUT MUST be measured and
          shall be referenced to the requested object(s).  The measurement
          will start on transmission of the first bit of the first requested
          object and end on transmission of the last bit of the last
          requested object.  The average transfer rate, in bits per second,
          will be calculated using the following formula:

                                 OBJECTS * OBJECTSIZE * 8
       TRANSFER RATE (bit/s) =  --------------------------
                                        DURATION

       OBJECTS    - Total number of objects successfully transferred across
                    all connections.

       OBJECTSIZE - Object size in bytes

       DURATION   - Aggregate transfer time based on aforementioned time
                    references.

    5.6.4.2 Measurements at or below the Transport-Layer

       The following measurements SHOULD be performed for each connection-
       oriented protocol:

       Goodput [1]:
          Goodput as defined in section 3.17 of RFC 2647.  Measurements MUST
          only reference the protocol payload, excluding any of the protocol
          header.  In addition, the test instrument MUST exclude any bits
          associated with the connection establishment, connection tear
          down, security associations [1] or connection maintenance [1].

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          Since connection-oriented protocols require that data be
          acknowledged, the offered load [4] will be varying.  Therefore,
          the test instrument should measure the average forwarding rate
          over the duration of the test.  Measurement should start on
          transmission of the first bit of the payload of the first datagram
          and end on transmission of the last bit of the payload of the last
          datagram.

       Number of bytes transferred - Total payload bytes transferred.

       Number of Timeouts - Total number of timeout events.

       Retransmitted bytes - Total number of retransmitted bytes.

    5.6.5 Reporting Format

       The test report MUST conform to the reporting requirements set in
       section 4, Test Setup.

    5.6.5.1 Application-Layer reporting

       The test report MUST note number of GET requests per connection and
       object size(s).

       The transfer rate results SHOULD be reported in tabular form with a
       column for each of the object sizes tested.  There SHOULD be a row
       for the number and percentage of completed requests, number and
       percentage of completed responses, and the resultant transfer rate
       for each iteration of the test.

       Failure analysis:
          The test report SHOULD indicate the number and percentage of HTTP
          GET request and responses that failed to complete.

       Version information:
          The test report MUST note the version of HTTP client(s) and
          server(s).

    5.6.5.2 Transport-Layer and below reporting

       The test report MUST note the number of connections, close method,
       close direction and the protocol for which the measurement was made.

       The results SHOULD be reported in tabular form for each of the HTTP
       object sizes tested.  There SHOULD be a row for the total bytes
       transferred, total timeouts, total retransmitted bytes and and
       resultant goodput.  Note that total bytes refers to total datagram
       payload bytes transferred.  The table MAY be combined with the

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       application layer reporting, provided the table clearly identifies
       the protocol for which the measurement was made.

       Failure analysis:
          The test report SHOULD indicate the number and percentage of
          connection establishment failures as well as number and percentage
          of TCP tear down failures.

       It is RECOMMENDED that the report include a graph to plot the
       distribution of both connection establishment failures and connection
       tear down failures.  The x coordinate SHOULD be the elapsed test
       time, the y coordinate SHOULD be the number of failures for a given
       sampling period.  There SHOULD be two lines on the graph, one for
       connection failures and one for tear down failures.  The graph MUST
       note the sampling period.

    5.7 Maximum HTTP Transaction Rate

    5.7.1 Objective

       Determine the maximum transaction rate the DUT/SUT can sustain.  This
       test is intended to find the maximum rate at which users can access
       objects.

    5.7.2 Setup Parameters

    5.7.2.1 Transport-Layer Setup Parameters

       Close Method:
          Defines method for closing TCP connections.  The test MUST be
          performed with either a three-way or four-way handshake.  In a
          four-way handshake, each side sends separate FIN and ACK messages.
          In a three-way handshake, one side sends a combined FIN/ACK
          message upon receipt of a FIN.

       Close Direction:
          Defines whether closing of connections are to be initiated from
          the client or from the server.

    5.7.2.2 Application-Layer Setup Parameters

       Session Type:
          HTTP 1.1 or higher MUST be used for this test.  The client and
          server MUST use the same HTTP version.

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       Test Duration:
          Time, expressed in seconds, for which the virtual client(s) will
          sustain the attempted GET request rate.  It is RECOMMENDED that
          the duration be at least 30 seconds.

       Requests per connection:
          Number of object requests per connection.

       Object Size:
          Defines the number of bytes, excluding any bytes associated with
          the HTTP header, to be transferred in response to an HTTP 1.1 or
          higher GET request.

    5.7.3 Procedure

       This test will employ an iterative search algorithm to determine the
       maximum transaction rate that the DUT/SUT can sustain.

       For each iteration, HTTP 1.1 or higher virtual client(s) will vary
       the aggregate GET request rate offered to HTTP 1.1 or higher
       server(s).  The virtual client(s) will maintain the offered request
       rate for the defined test duration.

       If the virtual client(s) make multiple HTTP GET requests per
       connection, it MUST request the same object size for each GET
       request.  Multiple tests MAY be performed with different object
       sizes.

    5.7.4 Measurements

       Maximum Transaction Rate:
          The maximum rate at which all transactions, that is all
          requests/responses cycles, are completed.

       Transaction Time:
          The test instrument SHOULD measure minimum, maximum and average
          transaction times.  The transaction time will start when the
          virtual client issues the GET request and end when the requesting
          virtual client receives the last bit of the requested object.

    5.7.5 Reporting Format

       The test report MUST conform to the reporting requirements set in
       section 4, Test Setup.

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    5.7.5.1 Application-Layer reporting

       The test report MUST note the test duration, object size, requests
       per connection, minimum transaction time, maximum transaction time,
       average transaction time and maximum transaction rate measured

       The intermediate results of the search algorithm MAY be reported in a
       table format with a column for each iteration.  There SHOULD be rows
       for the GET request attempt rate, number of requests attempted,
       number and percentage of requests completed, number of responses
       attempted, number and percentage of responses completed, minimum
       transaction time, average transaction time and maximum transaction
       time.

       Version information:
          The test report MUST note the version of HTTP client(s) and
          server(s).

    5.7.5.2 Transport-Layer

       The test report MUST note the close method, close direction, number
       of connections established and number of connections torn down.

       The intermediate results of the search algorithm MAY be reported in a
       table format with a column for each iteration.  There SHOULD be rows
       for the number of connections attempted, number and percentage of
       connections completed, number and percentage of connection tear downs
       completed.  The table MAY be combined with the application layer
       reporting, provided the table identify this as transport layer
       measurement.

    5.8  Illegal Traffic Handling

    5.8.1 Objective

       To characterize the behavior of the DUT/SUT when presented with a
       combination of both legal and Illegal [1] traffic.  Note that Illegal
       traffic does not refer to an attack, but traffic which has been
       explicitly defined by a rule(s) to drop.

    5.8.2 Setup Parameters

       Setup parameters will use the same parameters as specified in the
       HTTP transfer rate test (Section 5.6.2).  In addition, the following
       setup parameters MUST be defined:

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       Illegal traffic percentage:
          Percentage of HTTP 1.1 or higher connections which have been
          explicitly defined in a rule(s) to drop.

    5.8.3 Procedure

       Each HTTP 1.1 or higher client will request one or more objects from
       an HTTP 1.1 or higher server using one or more HTTP GET requests over
       each connection.  The aggregate number of connections attempted,
       defined by number of connections, MUST be evenly divided among all of
       the participating virtual clients.

       The virtual client(s) MUST offer the connection requests, both legal
       and illegal, in an evenly distributed manner.  Many firewalls have
       the capability to filter on different traffic criteria (IP addresses,
       Port numbers, etc.).  Multiple iterations of this test MAY be run
       with the DUT/SUT configured to filter on different traffic criteria.

    5.8.4 Measurements

       The same measurements as defined in HTTP transfer rate test (Section
       5.6.4) SHOULD be performed.  Any forwarding rate measurements MUST
       only include bits which are associated with legal traffic.

    5.8.5 Reporting Format

       Test reporting format SHOULD be the same as specified in the HTTP
       transfer rate test (Section 5.6.5).

       In addition, the report MUST note the percentage of illegal HTTP
       connections.

       Failure analysis:
          Test report MUST note the number and percentage of illegal
          connections that were allowed by the DUT/SUT.

    5.9 IP Fragmentation Handling

    5.9.1 Objective

       To determine the performance impact when the DUT/SUT is presented
       with IP fragmented traffic.  IP packets which have been fragmented,
       due to crossing a network that supports a smaller MTU (Maximum
       Transmission Unit) than the actual IP packet, may require the
       firewall to perform re-assembly prior to the rule set being applied.

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       While IP fragmentation is a common form of attack, either on the
       firewall itself or on internal hosts, this test will focus on
       determining how the additional processing associated with the re-
       assembly of the packets have on the forwarding rate of the DUT/SUT.
       RFC 1858 addresses some fragmentation attacks that get around IP
       filtering processes used in routers and hosts.

    5.9.2 Setup Parameters

       The following parameters MUST be defined.

    5.9.2.1 Non-Fragmented Traffic Parameters

       Setup parameters will be the same as defined in the HTTP transfer
       rate test (Sections 5.6.2.1 and 5.6.2.2).

    5.9.2.2 Fragmented Traffic Parameters

       Packet size:
          Number of bytes in the IP/UDP packet, exclusive of link-layer
          headers and checksums, prior to fragmentation.

       MTU:
          Maximum transmission unit, expressed in bytes.  For testing
          purposes, this MAY be configured to values smaller than the MTU
          supported by the link layer.

       Intended Load:
          Intended load, expressed as percentage of media utilization.

    5.9.3 Procedure

       Each HTTP 1.1 or higher client will request one or more objects from
       an HTTP 1.1 or higher server using one or more HTTP GET requests over
       each connection.  The aggregate number of connections attempted,
       defined by number of connections, MUST be evenly divided among all of
       the participating virtual clients.  If the virtual client(s) make
       multiple HTTP GET requests per connection, it MUST request the same
       object size for each GET request.

       A test instrument attached to the unprotected side of the network,
       will offer a unidirectional stream of unicast fragmented IP/UDP
       traffic, targeting a server attached to either the protected or DMZ
       segment. The test instrument MUST offer the unidirectional stream
       over the duration of the test, that is, duration over which the HTTP
       traffic is being offered.

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       Baseline measurements SHOULD be performed with IP filtering deny
       rule(s) to filter fragmented traffic.  If the DUT/SUT has logging
       capability, the log SHOULD be checked to determine if it contains the
       correct information regarding the fragmented traffic.

       The test SHOULD be repeated with the DUT/SUT rule set changed to
       allow the fragmented traffic through.  When running multiple
       iterations of the test, it is RECOMMENDED to vary the MTU while
       keeping all other parameters constant.

       Then setup the DUT/SUT to the policy or rule set the manufacturer
       required to be defined to protect against fragmentation attacks and
       repeat the measurements outlined in the baseline procedures.

    5.9.4 Measurements

       Test instrument SHOULD perform the same measurements as defined in
       HTTP test (Section 5.6.4).

       Transmitted UDP/IP Packets:
          Number of UDP packets transmitted by client.

       Received UDP/IP Packets:
          Number of UDP/IP Packets received by server.

    5.9.5 Reporting Format

    5.9.5.1 Non-Fragmented Traffic

       The test report SHOULD be the same as described in section 5.6.5.
       Note that any forwarding rate measurements for the HTTP traffic
       excludes any bits associated with the fragmented traffic which may be
       forward by the DUT/SUT.

    5.9.5.2 Fragmented Traffic

       The test report MUST note the packet size, MTU size, intended load,
       number of UDP/IP packets transmitted and number of UDP/IP packets
       forwarded.  The test report SHOULD also note whether or not the
       DUT/SUT forwarded the offered UDP/IP traffic fragmented.

    5.10 Latency

    5.10.1 Objective

       To determine the latency of network-layer or application-layer data
       traversing the DUT/SUT. RFC 1242 [3] defines latency.

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    5.10.2 Setup Parameters

       The following parameters MUST be defined:

    5.10.2.1 Network-layer Measurements

       Packet size, expressed as the number of bytes in the IP packet,
       exclusive of link-layer headers and checksums.

       Intended load, expressed as percentage of media utilization.

       Test duration, expressed in seconds.

       The test instruments MUST generate packets with unique timestamp
       signatures.

    5.10.2.2 Application-layer Measurements

       Object Size:
          Defines the number of bytes, excluding any bytes associated with
          the HTTP header, to be transferred in response to an HTTP 1.1 or
          higher GET request.  The minimum object size supported by the
          media SHOULD be used, but other object sizes MAY be used as well.

       Connection type:
          The test instrument MUST use one HTTP 1.1 or higher connection for
          latency measurements.

       Number of objects requested.

       Number of objects transferred.

       Test duration, expressed in seconds.

       Test instruments MUST generate packets with unique timestamp
       signatures.

    5.10.3 Network-layer procedure

       A client will offer a unidirectional stream of unicast packets to a
       server.  The packets MUST use a connectionless protocol like IP or
       UDP/IP.

       The test instrument MUST offer packets in a steady state.  As noted
       in the latency discussion in RFC 2544 [2], latency measurements MUST
       be taken at the throughput level, that is, at the highest offered
       load with zero packet loss.  Measurements taken at the throughput
       level are the only ones that can legitimately be termed latency.

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       It is RECOMMENDED that implementers use offered loads not only at the
       throughput level, but also at load levels that are less than or
       greater than the throughput level.  To avoid confusion with existing
       terminology, measurements from such tests MUST be labeled as delay
       rather than latency.

       It is RECOMMENDED to perform the latency measurements with different
       packet sizes.  When testing with different packet sizes the DUT/SUT
       configuration MUST remain the same.

       If desired, a step test MAY be used in which offered loads increment
       or decrement through a range of load levels.

       The duration of the test portion of each trial MUST be at least 30
       seconds.

    5.10.4 Application layer procedure

       An HTTP 1.1 or higher client will request one or more objects from an
       HTTP 1.1 or higher server using one or more HTTP GET requests.  If
       the test instrument makes multiple HTTP GET requests, it MUST request
       the same-sized object each time.  Multiple iterations of this test
       may be performed with objects of different sizes.

       Implementers MAY configure the test instrument to run for a fixed
       duration.  In this case, the test instrument MUST report the number
       of objects requested and returned for the duration of the test.  For
       fixed-duration tests it is RECOMMENDED that the duration be at least
       30 seconds.

    5.10.5 Measurements

       Minimum delay:
          The smallest delay incurred by data traversing the DUT/SUT at the
          network layer or application layer, as appropriate.

       Maximum delay:
          The largest delay incurred by data traversing the DUT/SUT at the
          network layer or application layer, as appropriate.

       Average delay:
          The mean of all measurements of delay incurred by data traversing
          the DUT/SUT at the network layer or application layer, as
          appropriate.

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       Delay distribution:
          A set of histograms of all delay measurements observed for data
          traversing the DUT/SUT at the network layer or application layer,
          as appropriate.

    5.10.6 Network-layer reporting format

       The test report MUST note the packet size(s), offered load(s) and
       test duration used. In addition, the test report MUST conform to the
       reporting requirements set in section 4, Test Setup.

       The latency results SHOULD be reported in the format of a table with
       a row for each of the tested packet sizes.  There SHOULD be columns
       for the packet size, the intended rate, the offered rate, and the
       resultant latency or delay values for each test.

    5.10.7 Application-layer reporting format

       The test report MUST note the object size(s) and number of requests
       and responses completed.  If applicable, the report MUST note the
       test duration if a fixed duration was used. In addition, the test
       report MUST conform to the reporting requirements set in section 4,
       Test Setup.

       The latency results SHOULD be reported in the format of a table with
       a row for each of the object sizes.  There SHOULD be columns for the
       object size, the number of completed requests, the number of
       completed responses, and the resultant latency or delay values for
       each test.

       Failure analysis:
          The test report SHOULD indicate the number and percentage of HTTP
          GET request or responses that failed to complete within the test
          duration.

       Version information:
          The test report MUST note the version of HTTP client and server.

    6. References

    6.1  Normative References

       [1]  Newman, D., "Benchmarking Terminology for Firewall Devices", RFC
            2647, August 1999.

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

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       [3]  Bradner, S., "Benchmarking Terminology for Network
            Interconnection Devices", RFC 1242, July 1991.

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

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

    6.2  Informative References

       [6]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L.,
            Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol -
            HTTP/1.1", RFC 2616, June 1999.

       [7]  Clark, D., "IP Datagram Reassembly Algorithm", RFC 815, July
            1982.

       [8]  Postel, J., "Transmission Control Protocol", STD 7, RFC 793,
            September 1981.

    7. Security Considerations

       The primary goal of this document is to provide methodologies in
       benchmarking firewall performance. While there is some overlap
       between performance and security issues, assessment of firewall
       security is outside the scope of this document.

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    APPENDIX A: HTTP (HyperText Transfer Protocol)

       The most common versions of HTTP in use today are HTTP/1.0 and
       HTTP/1.1 with the main difference being in regard to persistent
       connections.  HTTP 1.0, by default, does not support persistent
       connections.  A separate TCP connection is opened up for each GET
       request the client wants to initiate and closed after the requested
       object transfer is completed.  While some implementations HTTP/1.0
       supports persistence through the use of a keep-alive, there is no
       official specification for how the keep-alive operates. In addition,
       HTTP 1.0 proxies do support persistent connection as they do not
       recognize the connection header.

       HTTP/1.1, by default, does support persistent connection and is
       therefore the version that is referenced in this methodology. Proxy
       based DUT/SUTs may monitor the TCP connection and after a timeout,
       close the connection if no activity is detected.  The duration of
       this timeout is not defined in the HTTP/1.1 specification and will
       vary between DUT/SUTs.  If the DUT/SUT closes inactive connections,
       the aging timer on the DUT SHOULD be configured for a duration that
       exceeds the test time.

       While this document cannot foresee future changes to HTTP and it
       impact on the methodologies defined herein, such changes should be
       accommodated for so that newer versions of HTTP may be used in
       benchmarking firewall performance.

    APPENDIX B: Connection Establishment Time Measurements

       Some connection oriented protocols, such as TCP, involve an odd
       number of messages when establishing a connection.  In the case of
       proxy based DUT/SUTs, the DUT/SUT will terminate the connection,
       setting up a separate connection to the server.  Since, in such
       cases, the test instrument does not own both sides of the connection,
       measurements will be made two different ways.  While the following
       describes the measurements with reference to TCP, the methodology may
       be used with other connection oriented protocols which involve an odd
       number of messages.

       When testing non-proxy based DUT/SUTs , the establishment time shall
       be directly measured and is considered to be from the time the first
       bit of the first SYN packet is transmitted by the client to the time
       the last bit of the final ACK in the three-way handshake is received
       by the target server.

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       If the DUT/SUT is proxy based, the connection establishment time is
       considered to be from the time the first bit of the first SYN packet
       is transmitted by the client to the time the client transmits the
       first bit of the first acknowledged TCP datagram (t4-t0 in the
       following timeline).

          t0: Client sends a SYN.
          t1: Proxy sends a SYN/ACK.
          t2: Client sends the final ACK.
          t3: Proxy establishes separate connection with server.
          t4: Client sends TCP datagram to server.
          *t5: Proxy sends ACK of the datagram to client.

       * While t5 is not considered part of the TCP connection
       establishment, acknowledgement of t4 must be received for the
       connection to be considered successful.

    APPENDIX C: Connection Tear Down Time Measurements

       While TCP connections are full duplex, tearing down of such
       connections are performed in a simplex fashion, that is, FIN segments
       are sent by each host/device terminating each side of the TCP
       connection.

       When making connection tear down times measurements, such
       measurements will be made from the perspective of the entity, that
       is, virtual client/server initiating the connection tear down
       request.  In addition, the measurement will be performed in the same
       manner, independent of whether or not the DUT/SUT is proxy-based. The
       connection tear down will be considered the interval between the
       transmission of the first bit of the first TCP FIN packet transmitted
       by the virtual client or server, whichever is applicable, requesting
       a connection tear down to receipt of the last bit of the
       corresponding ACK packet on the same virtual client/server interface.

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    RFC 3511          Methodology for Firewall Performance        April 2003

    Authors' Addresses

       Brooks Hickman
       Spirent Communications
       26750 Agoura Road
       Calabasas, CA 91302
       USA

       Phone: + 1 818 676 2412
       EMail: brooks.hickman@spirentcom.com

       David Newman
       Network Test Inc.
       31324 Via Colinas, Suite 113
       Westlake Village, CA 91362-6761
       USA

       Phone: + 1 818 889-0011
       EMail: dnewman@networktest.com

       Saldju Tadjudin
       Spirent Communications
       26750 Agoura Road
       Calabasas, CA 91302
       USA

       Phone: + 1 818 676 2468
       EMail: Saldju.Tadjudin@spirentcom.com

       Terry Martin
       GVNW Consulting Inc.
       8050 SW Warm Springs Road
       Tualatin Or. 97062
       USA

       Phone: + 1 503 612 4422
       EMail: tmartin@gvnw.com

    Hickman, et al.              Informational                     [Page 33]

    RFC 3511          Methodology for Firewall Performance        April 2003

    Full Copyright Statement

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    Acknowledgement

       Funding for the RFC Editor function is currently provided by the
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