Network Working Group Brooks Hickman
Internet-Draft Spirent Communications
Expiration Date: December 2001 David Newman
Network Test
Terry Martin
M2networx INC
June 2001
Benchmarking Methodology for Firewall Performance
<draft-ietf-bmwg-firewall-02.txt>
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. Test setup . . . . . . . . . . . . . . . . . . . . . . . . . 2
4.1 Test Considerations . . . . . . . . . . . . . . . . . . 3
4.2 Virtual Client/Servers . . . . . . . . . . . . . . . . . 3
4.3 Test Traffic Requirements . . . . . . . . . . . . . . . . 4
4.4 DUT/SUT Traffic Flows . . . . . . . . . . . . . . . . . . 4
4.5 Multiple Client/Server Testing . . . . . . . . . . . . . 5
4.6 NAT(Network Address Translation) . . . . . . . . . . . . 5
4.7 Rule Sets . . . . . . . . . . . . . . . . . . . . . . . . 5
4.8 Web Caching . . . . . . . . . . . . . . . . . . . . . . . 5
4.9 Authentication . . . . . . . . . . . . . . . . . . . . . 6
5. Benchmarking Tests . . . . . . . . . . . . . . . . . . . . . 6
5.1 Concurrent Connection Capacity . . . . . . . . . . . . . 6
5.2 Maximum Connection Setup Rate . . . . . . . . . . . . . . 7
5.3 Connection Establishment Time . . . . . . . . . . . . . . 9
5.4 Connection Teardown Time . . . . . . . . . . . . . . . . 11
5.5 Denial Of Service Handling . . . . . . . . . . . . . . . 13
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5.6 HTTP . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.7 IP Fragmentation Handling . . . . . . . . . . . . . . . . 16
5.8 Illegal Traffic Handling . . . . . . . . . . . . . . . . 18
5.9 Latency . . . . . . . . . . . . . . . . . . . . . . . . . 19
Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . 22
A. HyperText Transfer Protocol(HTTP) . . . . . . . . . . . . 22
B. References . . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction
This document provides methodologies for the performance
benchmarking of firewalls. It provides methodologies in four areas:
forwarding, connection, latency and filtering. In addition to
defining the tests, this document also describes specific formats
for reporting the results of the tests.
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
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC 2119.
3. Scope
Firewalls can provide a single point of defense between networks.
Usually, a firewall protects private networks from the public or
shared networks to which it is connected. A firewall can be as
simple as a device that filters different packets or as complex
as a group of devices that combine packet filtering and
application-level proxy or network translation services. This RFC
will focus on developing benchmark testing of DUT/SUTs, wherever
possible, independent of their 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, typically the public network(Internet). The other interface
is connected to the protected network, typically the internal LAN.
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In the case of dual-homed configurations, servers which are made
accessible to the public(Unprotected) network are attached to the
private(Protected) network.
+----------+ +----------+
| | | +----------+ | | |
| Servers/ |----| | | |------| Servers/ |
| Clients | | | | | | Clients |
| | |-------| DUT/SUT |--------| | |
+----------+ | | | | +----------+
| +----------+ |
Protected | | Unprotected
Network Network
Figure 1(Dual-Homed)
Tri-homed[1] configurations employ a third segment called a 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 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
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a unique physical interface. For example, four virtual clients may
originate from the same data source[1]. The test report SHOULD
indicate the number of virtual clients and virtual servers
participating in the test on a per interface(See 4.1.3) basis.
Testers MUST synchronize all data sources participating in a 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. Therefore, the test equipment used to
benchmark the DUT/SUT performance MUST consist of real clients and
servers generating legitimate layer seven conversations.
For the purposes of benchmarking firewall performance, HTTP 1.1
will be referenced in this document, although 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
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4.5 Multiple Client/Server Testing
One or more clients may target multiple servers for a given
application. Each virtual client MUST initiate requests(Connection,
object transfers, etc.) in a round-robin fashion. For example, if
the test consisted of six virtual clients targeting three servers,
the pattern would be as follows:
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 NAT(Network Address Translation)
Many firewalls implement network address translation(NAT), a
function which translates internal host IP addresses attached to
the protected network to a virtual IP address for communicating
across the unprotected network(Internet). 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 differentials. The test report SHOULD
indicate whether NAT was enabled or disabled.
4.7 Rule Sets
Rule sets[1] are a collection of access control policies that
determines which packets the DUT/SUT will forward and which it will
reject. The criteria by which these access control policies may be
defined will vary depending on the capabilities of the DUT/SUT. The
scope of this document is limited to how the rule sets should be
applied when testing the DUT/SUT.
The firewall monitors the incoming traffic and checks to make sure
that the traffic meets one of the defined rules before allowing it
to be forwarded. It is RECOMMENDED that a rule be entered for each
host(Virtual client). Although many firewalls permit groups of IP
addresses to be defined for a given rule, tests SHOULD be performed
with large rule sets, which are more stressful to the DUT/SUT.
The DUT/SUT SHOULD be configured to denies access to all traffic
which was not previously defined in the rule set.
4.7 Web Caching
Some firewalls include caching agents in order to reduce network
load. When making a request through a caching agent, the caching
agent attempts to service the response from its internal memory.
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The cache itself saves responses it receives, such as responses
for HTTP GET requests. The report SHOULD indicate whether caching
was enabled or disabled on the DUT/SUT.
4.8 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 servers and may add to the latency of the system.
Any authentication processes MUST be included as part of connection
setup process.
5. Benchmarking Tests
5.1 Concurrent Connection Capacity
5.1.1 Objective
To determine the maximum number of concurrent connections through
or with the DUT/SUT, as defined in RFC2647[1]. This test will employ
a step algorithm to obtain the maximum number of concurrent TCP
connections that the DUT/SUT can maintain.
5.1.2 Setup Parameters
The following parameters MUST be defined for all tests.
Connection Attempt Rate - The rate, expressed in connections per
second, at which new TCP connection requests are attempted. The
rate SHOULD be set lower than maximum rate at which the DUT/SUT can
accept connection requests.
Connection Step Count - Defines the number of additional TCP
connections attempted for each iteration of the step search
algorithm.
Object Size - Defines the number of bytes to be transferred in
response to a HTTP 1.1 GET request . It is RECOMMENDED to use the
minimum object size supported by the media.
5.1.3 Procedure
Each virtual client will attempt to establish TCP connections to its
target server(s), using either the target server's IP address or NAT
proxy address, at a fixed rate in a round robin fashion. Each
iteration will involve the virtual clients attempting to establish a
fixed number of additional TCP connections. This search algorithm
will be repeated until either:
- One or more of the additional connection attempts fail to
complete.
- One or more of the previously established connections fail.
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The test MUST also include application layer data transfers in
order to validate the TCP connections since, in the case of proxy
based DUT/SUTs, the tester does not own both sides of the
connection. For the purposes of validation, the virtual client(s)
will request an object from its target server(s) using an HTTP 1.1
GET request, with both the client request and server response
excluding the connection-token close in the connection header. In
addition, periodic HTTP GET requests MAY be required to keep the
underlying TCP connection open(See Appendix A).
5.1.4 Measurements
Maximum concurrent connections - Total number of TCP connections
open for the last successful iteration performed in the search
algorithm.
5.1.5 Reporting Format
5.1.5.1 Transport-Layer Reporting:
The test report MUST note the connection attempt rate, connection
step count and maximum concurrent connections measured.
5.1.5.2 Application-Layer Reporting:
The test report MUST note the object size(s) and the use of
HTTP 1.1 client and server.
5.1.5.3 Log Files
A log file MAY be generated which includes the TCP connection
attempt rate, HTTP object size and for each iteration:
- Step Iteration
- Pass/Fail Status.
- Total TCP connections established.
- Number of previously established TCP connections dropped.
- Number of the additional TCP connections that failed to
complete.
5.2 Maximum Connection Setup Rate
5.2.1 Objective
To determine the maximum TCP connection setup rate through or with
the DUT/SUT, as defined by RFC2647[1]. This test will employ a
search algorithm to obtain the maximum rate at which TCP connections
can be established through or with the DUT/SUT.
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5.2.2 Setup Parameters
The following parameters MUST be defined.
Initial Attempt Rate - The rate, expressed in connections per
second, at which the initial TCP connection requests are attempted.
Number of Connections - Defines the number of TCP connections that
must be established. The number MUST be between the number of
participating virtual clients and the maximum number supported by
the DUT/SUT. It is RECOMMENDED not to exceed the concurrent
connection capacity found in section 5.1.
Connection Teardown Rate - The rate, expressed in connections per
second, at which the tester will attempt to teardown TCP connections
between each iteration. The connection teardown rate SHOULD be set
lower than rate at which the DUT/SUT can teardown TCP connections.
Age 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.
Object Size - Defines the number of bytes to be transferred in
response to a HTTP 1.1 GET request . It is RECOMMENDED to use the
minimum object size supported by the media.
5.2.3 Procedure
An iterative search algorithm will be used to determine the maximum
connection rate. This test iterates through different connection rates
with a fixed number of connections attempted by the virtual clients to
their associated server(s).
Each iteration will use the same connection establishment and
connection validation algorithms defined in the concurrent capacity
test(See section 5.1).
Between each iteration of the test, the tester must close all
connections completed for the previous iteration. In addition,
it is RECOMMENDED to abort all unsuccessful connections attempted.
The tester will wait for the period of time, specified by age time,
before continuing to the next iteration.
5.2.4 Measurements
Highest connection rate - Highest rate, in connections per second,
for which all TCP connections completed successfully.
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5.2.5 Reporting Format
5.2.5.1 Transport-Layer Reporting:
The test report MUST note the number of connections attempted,
connection teardown rate, age time, and highest connection rate
measured.
5.1.5.2 Application-Layer Reporting:
The test report MUST note the object size(s) and the use of
HTTP 1.1 client and server.
5.1.5.3 Log Files
A log file MAY be generated which includes the total TCP connections
attempt, TCP connection teardown rate, age time, HTTP object size and
for each iteration:
- Step Iteration
- Pass/Fail Status.
- Total TCP connections established.
- Number of TCP connections that failed to complete.
5.3 Connection Establishment Time
5.3.1 Objective
To determine the connection establishment times[1] through or with
the DUT/SUT as a function of the number of open connections.
A connection for a client/server application is not atomic, in that
it not only involves transactions at the application layer, but
involves first establishing a connection using one or more underlying
connection oriented protocols(TCP, ATM, etc). Therefore, it is
encouraged to make separate measurements for each connection oriented
protocol required in order to perform the application layer
transaction.
5.3.2 Setup Parameters
The following parameters MUST be defined.
Connection Attempt Rate - The rate, expressed in connections per
second, at which new TCP connection requests are attempted. It is
RECOMMENDED not to exceed the maximum connection rate found in
section 5.2.
Connection Attempt Step count - Defines the number of additional
TCP connections attempted for each iteration of the step algorithm.
Maximum Attempt Connection Count - Defines the maximum number of
TCP connections attempted in the test. It is RECOMMENDED not to
exceed the concurrent connection capacity found in section 5.1.
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Object Size - Defines the number of bytes to be transferred in
response to a HTTP 1.1 GET request.
Number of requests - Defines the number of HTTP 1.1 GET requests
per connection. Note that connection, in this case, refers to the
underlying transport protocol.
5.3.3 Procedure
Each virtual client will attempt to establish TCP connections to its
target server(s) at a fixed rate in a round robin fashion. Each
iteration will involve the virtual clients attempting to establish
a fixed number of additional connections until the maximum attempt
connection count is reached.
As with the concurrent capacity tests, application layer data
transfers will be performed. Each virtual client(s) will request
one or more objects from its target server(s) using one or more
HTTP 1.1 GET request, with both the client request and server
response excluding the connection-token close in the connection
header. In addition, periodic HTTP GET requests MAY be required to
keep the underlying TCP connection open(See appendix A).
Since testing may involve proxy based DUT/SUTs, which terminates the
TCP connection, making a direct measurement of the TCP connection
establishment time is not possible since the protocol involves an
odd number of messages in establishing a connection. Therefore, when
testing with proxy based firewalls, the datagram following the final
ACK on the three-way handshake will be used in determining the
connection setup time.
The following shows the timeline for the TCP connection setup
involving a proxy DUT/SUT and is referenced in the measurement
section. Note that this method may be applied when measuring other
connection oriented protocols involving an odd number of messages
in establishing a connection.
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.
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5.3.4 Measurements
For each iteration of the test, the tester MUST measure the minimum,
maximum and average TCP connection establishment times. Measuring TCP
connection establishment times will be made two different ways,
depending on whether or not the DUT/SUT is proxy based. If proxy
based, the connection establishment time is considered to be from the
time the first bit of the SYN packet is transmitted by the client to
the time the client transmits the first bit of the TCP datagram,
provided that the TCP datagram gets acknowledged(t4-t0 in the above
timeline). For DUT/SUTs that are not proxy based, the establishment
time shall be directly measured and is considered to be from the time
the first bit of the 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.
In addition, the tester SHOULD measure the minimum, maximum and
average connection establishment times for all other underlying
connection oriented protocols which are required to be established
for the client/server application to transfer an object. Each
connection oriented protocol has its own set of transactions
required for establishing a connection between two hosts or a host
and DUT/SUT. For purposes of benchmarking firewall performance, the
connection establishment time will be considered the interval
between the transmission of the first bit of the first octet of the
packet carrying the connection request to receipt of the last bit of
the last octet of the last packet of the connection setup traffic
received on the client or server, depending on whether a given
connection requires an even or odd number of messages, respectfully.
5.3.5 Reporting Format
The test report MUST note the TCP connection attempt rate, TCP
connection attempt step count and maximum TCP connections attempted,
HTTP object size and number of requests per connection.
For each connection oriented protocol the tester measured, the
connection establishment time results SHOULD be in tabular form
with a row for each iteration of the test. There SHOULD be a column
for the iteration count, minimum connection establishment time,
average connection establishment time, maximum connection
establishment time, attempted connections completed, attempted
connections failed.
5.4 Connection Teardown Time
5.4.1 Objective
To determine the connection teardown time[1] through or with the
DUT/SUT as a function of the number of open connections. As with the
connection establishment time, separate measurements will be taken
for each connection oriented protocol involved in closing a
connection.
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5.4.2 Setup Parameters
The following parameters MUST be defined. Each parameters is
configured with the following considerations.
Initial connections - Defines the number of TCP connections to
initialize the test with. It is RECOMMENDED not to exceed the
concurrent connection capacity found in section 5.1.
Initial connection rate - Defines the rate, in connections per
second, at which the initial TCP connections are attempted. It is
RECOMMENDED not to exceed the maximum Connection setup rate found
in section 5.2.
Teardown attempt rate - The rate at which the tester will attempt
to teardown TCP connections.
Teardown step count - Defines the number of TCP connections the
tester will attempt to teardown for each iteration of the step
algorithm.
Object size - Defines the number of bytes to be transferred across
each connection in response to an HTTP 1.1 GET request during the
initialization phase of the test as well as periodic GET requests,
if required.
5.4.3 Procedure
Prior to beginning a step algorithm, the tester will initialize
the test by establishing connections defined by initial connections.
The test will use the same algorithm for establishing the connection
as described in the connection capacity test(Section 5.1).
For each iteration of the step algorithm, the tester will attempt
teardown the number of connections defined by teardown step count
at a rate defined by teardown attempt rate. This will be repeated
until the tester has attempted to teardown all of the connections.
5.4.4 Measurements
For each iteration of the test, the tester MUST measure the minimum,
average and maximum connection teardown times. As with the
connection establishment time test, the tester SHOULD measure all
connection oriented protocols which are being torn down.
5.4.5 Reporting Format
The test report MUST note the initial connections, initial
connection rate, teardown attempt rate, teardown step count and
object size.
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For each connection oriented protocol the tester measured, the
connection teardown time results SHOULD be in tabular form
with a row for each iteration of the test. There SHOULD be a column
for the iteration count, minimum connection teardown time,
average connection teardown time, maximum connection teardown
time, attempted teardowns completed, attempted teardown failed.
5.5 Denial Of Service Handling
5.5.1 Objective
To determine the effect of a denial of service attack on a DUT/SUTs
connection establishment rates and/or goodput. The Denial Of Service
Handling test MUST be run after obtaining baseline measurements
from sections 5.2 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.
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 to determine how well the DUT/SUT can maintain,
under such attacks, the baseline connection rates and goodput determined
in section 5.2 and section 5.6, respectively.
5.5.2 Setup Parameters
Use the same setup parameters as defined in section 5.2.2 or 5.6.2,
depending on whether testing against the baseline connection setup
rate test or goodput test, respectfully.
In addition, the following setup parameters MUST be defined.
SYN Attack Rate - Defines the rate, in packets per second at which
the server(s) are targeted with TCP SYN packets.
5.5.3 Procedure
Use the same procedure as defined in section 5.2.3 or 5.6.3, depending
on whether testing against the baseline connection setup rate test or
goodput test, respectfully. In addition, the tester will generate TCP
SYN packets targeting the server(s) IP address or NAT proxy address at
a rate defined by SYN attack rate.
The tester originating the TCP SYN attack MUST be attached to the
unprotected network. In addition, the tester MUST not respond to the
SYN/ACK packets sent by target server in response to the SYN packet.
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5.5.4 Measurements
Perform the same measurements as defined in section 5.2.4 or 5.6.4,
depending on whether testing against the baseline connection setup
rate test or goodput test, respectfully.
In addition, the tester SHOULD track 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 5.2.5 or 5.6.5, depending on whether testing against
baseline throughput rates or goodput, respectively.
In addition, the report MUST indicate a denial of service handling
test, SYN attack rate, number SYN attack packets transmitted and
number of SYN attack packets received and whether or not the DUT
has any SYN attack mechanisms enabled.
5.6 HTTP
5.6.1 Objective
To determine the goodput, as defined by RFC2647, of the DUT/SUT
when presented with HTTP traffic flows. The goodput measurement
will be based on HTTP objects forwarded to the correct destination
interface of the DUT/SUT.
5.6.2 Setup Parameters
The following parameters MUST be defined.
Number of sessions - Defines the number of HTTP 1.1 sessions to be
attempted for transferring an HTTP object(s). Number MUST be equal
or greater than the number of virtual clients participating in the
test. The number SHOULD be a multiple of the virtual clients
participating in the test. Note that each session will use one
underlying transport layer connection.
Session rate - Defines the rate, in sessions per second, that the
HTTP sessions are attempted.
Requests per session - Defines the number of HTTP GET requests per
session.
Object Size - Defines the number of bytes to be transferred in
response to an HTTP GET request.
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5.6.3 HTTP Procedure
Each HTTP 1.1 virtual client will attempt to establish sessions
to its HTTP 1.1 target server(s), using either the target server's
IP address or NAT proxy address, at a fixed rate in a round robin
fashion.
Baseline measurements SHOULD be performed using a single GET request
per HTTP session with the minimal object size supported by the media.
If the tester makes multiple HTTP GET requests per session, it MUST
request the same-sized object each time. Testers may run multiple
iterations of this test with objects of different sizes. See
appendix A when testing proxy based DUT/SUT regarding HTTP version
considerations. 5.6.4 Measurement
Aggregate Goodput - The aggregate bit forwarding rate of the
requested HTTP objects. The measurement will start on receipt of the
first bit of the first packet containing a requested object which
has been successfully transferred and end on receipt of the last
packet containing the last requested object that has been
successfully transferred. The goodput, in bits per second, can be
calculated using the following formula:
OBJECTS * OBJECTSIZE * 8
Goodput = --------------------------
DURATION
OBJECTS - Objects successfully transferred
OBJECTSIZE - Object size in bytes
DURATION - Aggregate transfer time based on aforementioned time
references.
5.6.5 Reporting Format
The test report MUST note the object size(s), number of sessions,
session rate and requests per session.
The goodput results SHOULD be reported in tabular form with a row
for each of the object sizes. There SHOULD be columns for the object
size, measured goodput and number of successfully transferred
objects.
Failure analysis:
The test report SHOULD indicate the number and percentage of HTTP
sessions that failed to complete the requested number of
transactions, with a transaction being the GET request and
successfully returned object.
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Version information:
The test report MUST note the use of an HTTP 1.1 client and server.
5.7 IP Fragmentation
5.7.1 Objective
To determine the performance impact when the DUT/SUT is presented
with IP fragmented[5] traffic. IP datagrams which have been
fragmented, due to crossing a network that supports a smaller
MTU(Maximum Transmission Unit) than the actual datagram, may
require the firewall to perform re-assembly prior to the datagram
being applied to the rule set.
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 datagrams has on the goodput of the DUT/SUT.
5.7.2 Setup Parameters
The following parameters MUST be defined.
Trial duration - Trial duration SHOULD be set for 30 seconds.
5.7.2.1 Non-Fragmented Traffic Parameters
Session rate - Defines the rate, in sessions per second, that the
HTTP sessions are attempted.
Requests per session - Defines the number of HTTP GET requests per
session.
Object Size - Defines the number of bytes to be transferred in
response to an HTTP GET request.
5.7.2.1 Fragmented Traffic Parameters
Packet size, expressed as the number of bytes in the IP/UDP packet,
exclusive of link-layer headers and checksums.
Fragmentation Length - Defines the length of the data portion of the
IP datagram and MUST be multiple of 8. Testers SHOULD use the minimum
value, but MAY use other sizes as well.
Intended Load - Intended load, expressed as percentage of media
utilization.
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5.7.3 Procedure
Each HTTP 1.1 virtual client will attempt to establish sessions
to its HTTP 1.1 target server(s), using either the target server's
IP address or NAT proxy address, at a fixed rate in a round robin
fashion. At the same time, a client attached to the unprotected side
of the network will offer a unidirectional stream of unicast UDP/IP
packets to a server connected to the protected side of the network.
The tester MUST offer IP/UDP packets in a steady state.
Baseline measurements SHOULD be performed with a deny rule(s) that
filters the 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 fragment
length while keeping all other parameters constant.
5.7.4 Measurements
Aggregate Goodput - The aggregate bit forwarding rate of the
requested HTTP objects.(See section 5.6). Only objects which have
successfully completed transferring within the trial duration are
to be included in the goodput measurement.
Transmitted UDP/IP Packets - Number of UDP packets transmitted by
client.
Received UDP/IP Packets - Number of UDP/IP Packets received by
server.
5.7.5 Reporting Format
The test report MUST note the test duration.
The test report MUST note the packet size(s), offered load(s) and
IP fragmentation length of the UDP/IP traffic. It SHOULD also note
whether the DUT/SUT egresses the offered UDP/IP traffic fragmented
or not.
The test report MUST note the object size(s), session rate and
requests per session.
The results SHOULD be reported in the format of a table with a
row for each of the fragmentation lengths. There SHOULD be columns
for the fragmentation length, IP/UDP packets transmitted by client,
IP/UDP packets received by server, HTTP object size, and measured
goodput.
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5.8 Illegal Traffic Handling
5.8.1 Objective
To determine the behavior of the DUT/SUT when presented with a
combination of both legal and Illegal traffic flows. Note that
Illegal traffic does not refer to an attack, but to traffic which
has been explicitly defined by a rule(s) to drop.
5.8.2 Setup Parameters
The following parameters MUST be defined.
Number of sessions - Defines the number of HTTP 1.1 sessions to be
attempted for transferring an HTTP object(s). Number MUST be equal
or greater than the number of virtual clients participating in the
test. The number SHOULD be a multiple of the virtual clients
participating in the test. Note that each session will use one
underlying transport layer connection.
Session rate - Defines the rate, in sessions per second, that the
HTTP sessions are attempted.
Requests per session - Defines the number of HTTP GET requests per
session.
Object size - Defines the number of bytes to be transferred in
response to an HTTP GET request.
Illegal traffic percentage - Percentage of HTTP 1.1 sessions which
have been explicitly defined in a rule(s) to drop.
5.8.3 Procedure
Each HTTP 1.1 virtual client will attempt to establish sessions
to its HTTP 1.1 target server(s), using either the target server's
IP address or NAT proxy address, at a fixed rate in a round robin
fashion.
The tester MUST present 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). Testers may run multiple
iterations of this test with the DUT/SUT configured to filter
on different traffic criteria.
5.8.4 Measurements
Legal sessions allowed - Number and percentage of legal HTTP
sessions which completed.
Illegal session allowed - Number and percentage of illegal HTTP
session which completed.
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5.8.5 Reporting Format
The test report MUST note the number of sessions, session rate,
requests per session, percentage of illegal sessions and measurement
results. The results SHOULD be reported in the form of a table with a row
for each of the object sizes. There SHOULD be columns for the
object size, number of legal sessions attempted, number of legal
sessions successful, number of illegal sessions attempted and number
of illegal sessions successful.
5.9 Latency
5.9.1 Objective
To determine the latency of network-layer or application-layer data
traversing the DUT/SUT. RFC 1242 [3] defines latency.
5.9.2 Setup Parameters
The following parameters MUST be defined:
5.9.2.1 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.
Offered load, expressed as percentage of media utilization.
Test duration, expressed in seconds.
Test instruments MUST generate packets with unique timestamp signatures.
5.9.2.2 Application-layer Measurements
Object size, expressed as the number of bytes to be transferred across a
connection in response to an HTTP GET request. Testers SHOULD use the
minimum object size supported by the media, but MAY use other object
sizes as well.
Connection type. The tester MUST use one HTTP 1.1 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.
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5.9.3 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 tester MUST offer packets in a steady state. As noted in the latency
discussion in RFC 2544 [4], 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.
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.
If desired, the tester MAY use a step test 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.
5.9.4 Application layer procedure
An HTTP 1.1 client will request one or more objects from an HTTP 1.1 server
using one or more HTTP GET requests. If the tester makes multiple HTTP GET
requests, it MUST request the same-sized object each time. Testers may run
multiple iterations of this test with objects of different sizes.
Implementers MAY configure the tester to run for a fixed duration. In this
case, the tester 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.
5.9.5 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.
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.
5.9.6 Network-layer reporting format
The test report MUST note the packet size(s), offered load(s) and test
duration used.
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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.
5.9.7 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.
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 use of an HTTP 1.1 client and server.
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APPENDICES
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. Some implementations of
HTTP/1.0 supports persistence by adding an additional header
to the request/response:
Connection: Keep-Alive
However, under HTTP 1.0, 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.
When HTTP/1.1 entities want the underlying transport layer
connection closed after a transaction has completed, the
request/response will include a connection-token close in the
connection header:
Connection: close
If no such connection-token is present, the connection remains
open after the transaction is completed. In addition, 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. When performing
concurrent connection testing, GET requests MAY need to be
issued at a periodic rate so that the proxy does not close the
TCP connection.
While this document cannot foresee future changes to HTTP
and it's 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.
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Appendix B. References
[1] D. Newman, "Benchmarking Terminology for Firewall Devices", RFC 2647,
August 1999.
[2] R. Fielding, J. Gettys, J. Mogul, H Frystyk, L.Masinter, P. Leach,
T. Berners-Lee , "Hypertext Transfer Protocol -- HTTP/1.1",
RFC 2616 June 1999
[3] S. Bradner, editor. "Benchmarking Terminology for Network
Interconnection Devices," RFC 1242, July 1991.
[4] S. Bradner, J. McQuaid, "Benchmarking Methodology for Network
Interconnect Devices," RFC 2544, March 1999.
[5] David C. Clark, "IP Datagram Reassembly Algorithm", RFC 815 ,
July 1982.
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