As per Relevance of the word forwarding, we have this rfc below:
Network Working Group R.
Request for Comments: 2889 CQOS Inc
Category: Informational J.
Spirent
August 2000
Benchmarking Methodology for LAN Switching
Status of this
This memo provides information for the Internet community. It
not specify an Internet standard of any kind. Distribution of
memo is unlimited
Copyright
Copyright (C) The Internet Society (2000). All Rights Reserved
Table of
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Test setup . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. Frame formats and sizes . . . . . . . . . . . . . . . . . . . 3
5. Benchmarking Tests . . . . . . . . . . . . . . . . . . . . . . 3
5.1 Fully meshed throughput, frame loss and forwarding rates 4
5.2 Partially meshed one-to-many/many-to-one . . . . . . . . 7
5.3 Partially meshed multiple devices . . . . . . . . . . . . 10
5.4 Partially meshed unidirectional traffic . . . . . . . . . 13
5.5 Congestion Control . . . . . . . . . . . . . . . . . . . 16
5.6 Forward Pressure and Maximum Forwarding Rate . . . . . . 19
5.7 Address caching capacity . . . . . . . . . . . . . . . . 22
5.8 Address learning rate . . . . . . . . . . . . . . . . . . 25
5.9 Errored frames filtering. . . . . . . . . . . . . . . . . 27
5.10 Broadcast frame Forwarding and Latency . . . . . . . . . 28
6. Security Considerations . . . . . . . . . . . . . . . . . . . 30
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 30
Appendix A: Formulas . . . . . . . . . . . . . . . . . . . . . 31
Appendix B: Generating Offered Load . . . . . . . . . . . . . 32
Full Copyright Statement . . . . . . . . . . . . . . . . . . . 35
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RFC 2889 LAN Switch Benchmarking Methodology August 2000
1.
This document is intended to provide methodology for the
of local area network (LAN) switching devices. It extends
methodology already defined for benchmarking network
devices in RFC 2544 [3] to switching devices
This RFC primarily deals with devices which switch frames at
Medium Access Control (MAC) layer. It provides a methodology
benchmarking switching devices, forwarding performance,
control, latency, address handling and filtering. In addition
defining the tests, this document also describes specific formats
reporting the results of the tests
A previous document, "Benchmarking Terminology for LAN
Devices" [2], defined many of the terms that are used in
document. The terminology document SHOULD be consulted
attempting to make use of this document
2.
The following RFCs SHOULD be consulted before attempting to make
of this document: RFC 1242 [1], RFC 2285 [2], and RFC 2544 [3].
For the sake of clarity and continuity, this RFC adopts the
for benchmarking tests set out in Section 26 of RFC 2544.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
document are to be interpreted as described in RFC 2119.
3. Test
This document extends the general test setup described in section 6
of RFC 2544 [3] to the benchmarking of LAN switching devices.
2544 [3] primarily describes non-meshed traffic where input
output interfaces are grouped in mutually exclusive sending
receiving pairs. In fully meshed traffic, each interface of
DUT/SUT is set up to both receive and transmit frames to all
other interfaces under test
Prior to each test run, the DUT/SUT MUST learn the MAC addresses
in the test and the address learning SHOULD be verified.
not learned will be forwarded as flooded frames and reduce the
of correctly forwarded frames. The rate at which address
frames are offered may have to be adjusted to be as low as 50
per second or even less, to guarantee successful learning.
DUT/SUT address aging time SHOULD be configured to be greater
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RFC 2889 LAN Switch Benchmarking Methodology August 2000
the period of the learning phase of the test plus the trial
plus any configuration time required by the testing device
Addresses SHOULD NOT age out until the trial duration is completed
More than one learning trial may be needed for the association of
address to the port to occur
If a DUT/SUT uses a hashing algorithm with address learning,
DUT/SUT may not learn the necessary addresses to perform the tests
The format of the MAC addresses MUST be adjustable so that
address mapping may be re-arranged to ensure that the DUT/SUT
all the addresses
4. Frame formats and
The test frame format is defined in RFC 2544 section 8 [3] and
contain a unique signature field located in the UDP DATA area of
Test Frame (see Appendix C [3]). The purpose of the signature
is filter out frames that are not part of the offered load
The signature field MUST be unique enough to identify the frames
originating from the DUT/SUT. The signature field SHOULD be
after byte 56 (collision window [4] ) or at the end of the frame.
length, contents and method of detection is not defined in this memo
The signature field MAY have a unique identifier per port.
would filter out misforwarded frames. It is possible for a DUT/
to strip off the MAC layer, send it through its switching matrix,
transmit it out with the correct destination MAC address but
wrong payload
For frame sizes, refer to RFC 2544, section 9 [3].
There are three possible frame formats for layer 2 Ethernet switches
standard MAC Ethernet frames, standard MAC Ethernet frames
vendor-specific tags added to them, and IEEE 802.3ac frames tagged
accommodate 802.1p&Q. The two types of tagged frames may exceed
standard maximum length frame of 1518 bytes, and may not be
by the interface controllers of some DUT/SUTs. It is recommended
check the compatibility of the DUT/SUT with tagged frames
testing
Devices switching tagged frames of over 1518 bytes will have
different maximum forwarding rate than untagged frames
5. Benchmarking
The following tests offer objectives, procedures, and
formats for benchmarking LAN switching devices
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5.1 Fully meshed throughput, frame loss and forwarding
5.1.1
To determine the throughput, frame loss and forwarding rates
DUT/SUTs offered fully meshed traffic as defined in RFC 2285 [2].
5.1.2 Setup
When offering full meshed traffic, the following parameters MUST
defined. Each parameter is configured with the
considerations
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9 [3]. The four
bytes are included in the frame size specified
Interframe Gap (IFG) - The IFG between frames inside a burst
be at the minimum specified by the standard (9.6 us for 10
Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1
Ethernet) of the medium being tested
Duplex mode - Half duplex or full duplex
ILoad - Intended Load per port is expressed in a percentage of
medium's maximum theoretical load, regardless of
orientation or duplex mode. Certain test configurations
theoretically over-subscribe the DUT/SUT
In half duplex, an ILoad over 50% will over-subscribe the DUT/SUT
Burst Size - The burst size defines the number of frames
back-to-back at the minimum legal IFG [4] before
transmission to receive frames. Burst sizes SHOULD vary between 1
and 930 frames. A burst size of 1 will simulate constant
[1].
Addresses per port - Represents the number of addresses which
being tested for each port. Number of addresses SHOULD be
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended value is 1.
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
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5.1.3
All ports on the tester MUST transmit test frames either in a
Based or Time Based mode (Appendix B). All ports SHOULD
transmitting their frames within 1% of the trial duration. For
trial duration of 30 seconds, all ports SHOULD have
transmitting frames within 300 milliseconds of each other
Each port in the test MUST send test frames to all other ports in
round robin type fashion. The sequence of addresses MUST NOT
when congestion control is applied. The following table shows
each port in a test MUST transmit test frames to all other ports
the test. In this example, there are six ports with 1 address
port
Source Port Destination Ports (in order of transmission
Port #1 2 3 4 5 6 2...
Port #2 3 4 5 6 1 3...
Port #3 4 5 6 1 2 4...
Port #4 5 6 1 2 3 5...
Port #5 6 1 2 3 4 6...
Port #6 1 2 3 4 5 1...
As shown in the table, there is an equal distribution of
addresses for each transmit opportunity. This keeps the test
so that one destination port is not overloaded by the test
and all ports are equally and fully loaded throughout the test.
following this algorithm exactly will produce inconsistent results
For tests using multiple addresses per port, the actual
destinations are the same as described above and the
source/destination address pairs SHOULD be chosen randomly
exercise the DUT/SUT's ability to perform address lookups
For every address, learning frames MUST be sent to the DUT/SUT
allow the DUT/SUT update its address tables properly
5.1.4
Each port should receive the same number of test frames that
transmitted. Each receiving port MUST categorize, then count
frames into one of two groups
1.) Received Frames: received frames MUST have the
destination MAC address and SHOULD match a signature field
2.) Flood count [2].
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Any frame originating from the DUT/SUT (spanning tree, SNMP, RIP
...) MUST not be counted as a received frame. Frames
from the DUT/SUT MAY be counted as flooded frames or not counted
all
Frame loss rate of the DUT/SUT SHOULD be reported as defined
section 26.3 [3] with the following notes: Frame loss rate SHOULD
measured at the end of the trail duration. The term "rate", for
measurement only, does not imply the units in the fashion of "
second."
5.1.4.1
Throughput measurement is defined in section 26.1 [3]. A
algorithm is employed to find the maximum Oload [2] with a zero
loss rate [1]. The algorithm MUST adjust Iload to find
throughput
5.1.4.2 Forwarding
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the
of test frames per second that the device is observed to
forward to the correct destination interface in response to
specified Oload. The Oload MUST also be cited
Forwarding rate at maximum offered load (FRMOL) MUST be reported
the number of test frames per second that a device can
transmit to the correct destination interface in response to the
as defined in section 3.6 [2]. The MOL MUST also be cited
Maximum forwarding rate (MFR) MUST be reported as the
forwarding rate of a DUT/SUT taken from an iterative set
forwarding rate measurements. The iterative set of forwarding
measurements are made by adjusting Iload. The Oload applied to
device MUST also be cited
5.1.5 Reporting
The results for these tests SHOULD be reported in the form of
graph. The x coordinate SHOULD be the frame size, the y
SHOULD be the test results. There SHOULD be at least two lines
the graph, one plotting the theoretical and one plotting the
results
To measure the DUT/SUT's ability to switch traffic while
many different address lookups, the number of addresses per port
be increased in a series of tests
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5.2 Partially meshed one-to-many/many-to-
5.2.1
To determine the throughput when transmitting from/to multiple
and to/from one port. As with the fully meshed throughput test,
test is a measure of the capability of the DUT to switch
without frame loss. Results of this test can be used to
the ability of the DUT to utilize an Ethernet port when
traffic from multiple Ethernet ports
5.2.2 Setup
When offering bursty meshed traffic, the following parameters MUST
defined. Each parameter is configured with the
considerations
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9 [3]. The four
bytes are included in the frame size specified
Traffic Direction - Traffic can be generated in one direction,
reverse direction, or both directions
Interframe Gap (IFG) - The IFG between frames inside a burst
be at the minimum specified by the standard (9.6 us for 10
Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1
Ethernet) of the medium being tested
Duplex mode - Half duplex or full duplex
ILoad - Intended Load per port is expressed in a percentage of
medium's maximum theoretical load, regardless of
orientation or duplex mode. Certain test configurations
theoretically over-subscribe the DUT/SUT
In half duplex bidirectional traffic, an ILoad over 50%
over-subscribe the DUT/SUT
Burst Size - The burst size defines the number of frames
back-to-back at the minimum legal IFG [4] before
transmission to receive frames. Burst sizes SHOULD vary between 1
and 930 frames. A burst size of 1 will simulate constant
[1].
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Addresses per port - Represents the number of addresses which
being tested for each port. Number of addresses SHOULD be
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended value is 1.
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
5.2.3
All ports on the tester MUST transmit test frames either in a
Based or Time Based mode (Appendix B). Depending upon
direction, some or all of the ports will be transmitting. All
SHOULD start transmitting their frames within 1% of the
duration. For a trial duration of 30 seconds, all ports SHOULD
started transmitting frames within 300 milliseconds of each other
Test frames transmitted from the Many Ports MUST be destined to
One port. Test frames transmitted from the One Port MUST be
to the Many ports in a round robin type fashion. See section 5.1.3
for a description of the round robin fashion
For tests using multiple addresses per port, the actual
destinations are the same as described above and the
source/destination address pairs SHOULD be chosen randomly
exercise the DUT/SUT's ability to perform address lookups
+----------+
| |
| Many | <--------
| | \
+----------+ \
\
+----------+ \ +-------------+
| | ------------> | |
| Many | <-----------------------> | One |
| | ------------> | |
+----------+ / +-------------+
/
+----------+ /
| | /
| Many | <-------
| |
+----------+
For every address, the testing device MUST send learning frames
allow the DUT/SUT to update its address tables properly
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5.2.4
Each receiving port MUST categorize, then count the frames into
of two groups
1.) Received Frames: received frames MUST have the
destination MAC address and SHOULD match a signature field
2.) Flood count [2].
Any frame originating from the DUT/SUT MUST not be counted as
received frame. Frames originating from the DUT/SUT MAY be
as flooded frames or not counted at all
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the
of test frames per second that the device is observed to
transmit to the correct destination interface in response to
specified Oload. The Oload MUST also be cited
Forwarding rate at maximum offered load (FRMOL) MUST be reported
the number of test frames per second that a device can
transmit to the correct destination interface in response to the
as defined in section 3.6 [2]. The MOL MUST also be cited
Maximum forwarding rate (MFR) MUST be reported as the
forwarding rate of a DUT/SUT taken from an iterative set
forwarding rate measurements. The iterative set of forwarding
measurements are made by adjusting Iload. The Oload applied to
device MUST also be cited
5.2.5 Reporting
The results for these tests SHOULD be reported in the form of
graph. The x coordinate SHOULD be the frame size, the y
SHOULD be the test results. There SHOULD be at least two lines
the graph, one plotting the theoretical and one plotting the
results
To measure the DUT/SUT's ability to switch traffic while
many different address lookups, the number of addresses per port
be increased in a series of tests
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5.3 Partially meshed multiple
5.3.1
To determine the throughput, frame loss and forwarding rates of
switching devices equipped with multiple ports and one high
backbone uplink (Gigabit Ethernet, ATM, SONET).
5.3.2 Setup
When offering bursty partially meshed traffic, the
parameters MUST be defined. Each variable is configured with
following considerations
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9 [3]. The four
bytes are included in the frame size specified
Interframe Gap (IFG) - The IFG between frames inside a burst
be at the minimum specified by the standard (9.6 us for 10
Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1
Ethernet) of the medium being tested
Duplex mode - Half duplex or full duplex
ILoad - Intended Load per port is expressed in a percentage of
medium's maximum theoretical load, regardless of
orientation or duplex mode. Certain test configurations
theoretically over-subscribe the DUT/SUT
In half duplex, an ILoad over 50% will over-subscribe the DUT/SUT
Burst Size - The burst size defines the number of frames
back-to-back at the minimum legal IFG [4] before
transmission to receive frames. Burst sizes SHOULD vary between 1
and 930 frames. A burst size of 1 will simulate constant
[1].
Addresses per port - Represents the number of addresses which
being tested for each port. Number of addresses SHOULD be
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended value is 1.
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
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Local Traffic - A Boolean value of ON or OFF. The frame
algorithm MAY be altered to remove local traffic. With
traffic ON, the algorithm is exactly the same as a fully
throughput. With local traffic OFF, the port sends frames to
other ports on the other side of the backbone uplink in a
robin type fashion
5.3.3
All ports on the tester MUST transmit test frames either in a
Based or Time Based mode (Appendix B). All ports SHOULD
transmitting their frames within 1% of the trial duration. For
trial duration of 30 seconds, all ports SHOULD have
transmitting frames with 300 milliseconds of each other
Each port in the test MUST send test frames to all other ports in
round robin type fashion as defined in section 5.1.3. Local
MAY be removed from the round robin list in order to send the
load across the backbone uplink
For tests using multiple addresses per port, the actual
destinations are the same as described above and the
source/destination address pairs SHOULD be chosen randomly
exercise the DUT/SUT's ability to perform address lookups
For every address, the testing device MUST send learning frames
allow the DUT/SUT to update its address tables properly
To measure the DUT/SUT's ability to switch traffic while
many different address lookups, the number of addresses per port
be increased in a series of tests
5.3.4
Each receiving port MUST categorize, then count the frames into
of two groups
1.) Received frames MUST have the correct destination MAC
and SHOULD match a signature field
2.) Flood count [2].
Any frame originating from the DUT/SUT MUST not be counted as
received frame. Frames originating from the DUT/SUT MAY be
as flooded frames or not counted at all
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Frame loss rate of the DUT/SUT SHOULD be reported as defined
section 26.3 [3] with the following notes: Frame loss rate SHOULD
measured at the end of the trial duration. The term "rate", for
measurement only, does not imply the units in the fashion of "
second."
5.3.4.1
Throughput measurement is defined in section 26.1 [3]. A
algorithm is employed to find the maximum Oload [2] with a zero
loss rate [1]. The algorithm MUST adjust Iload to find
throughput
5.3.4.2 Forwarding
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the
of test frames per second that the device is observed to
forward to the correct destination interface in response to
specified Oload. The Oload MUST also be cited
Forwarding rate at maximum offered load (FRMOL) MUST be reported
the number of test frames per second that a device can
transmit to the correct destination interface in response to the
as defined in section 3.6 [2]. The MOL MUST also be cited
Maximum forwarding rate (MFR) MUST be reported as the
forwarding rate of a DUT/SUT taken from an iterative set
forwarding rate measurements. The iterative set of forwarding
measurements are made by adjusting Iload. The Oload applied to
device MUST also be cited
5.3.5 Reporting
The results for these tests SHOULD be reported in the form of
graph. The x coordinate SHOULD be the frame size, the y
SHOULD be the test results. There SHOULD be at least two lines
the graph, one plotting the theoretical and one plotting the
results
To measure the DUT/SUT's ability to switch traffic while
many different address lookups, the number of addresses per port
be increased in a series of tests
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5.4 Partially meshed unidirectional
5.4.1
To determine the throughput of the DUT/SUT when presented
streams of unidirectional traffic with half of the ports on
DUT/SUT are transmitting frames destined to the other half of
ports
5.4.2 Setup
The following parameters MUST be defined. Each variable
configured with the following considerations
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9 [3]. The four
bytes are included in the frame size specified
Interframe Gap (IFG) - The IFG between frames inside a burst
be at the minimum specified by the standard (9.6 us for 10
Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1
Ethernet) of the medium being tested
Duplex mode - Half duplex or full duplex
ILoad - Intended Load per port is expressed in a percentage of
medium's maximum theoretical load, regardless of
orientation or duplex mode. Certain test configurations
theoretically over-subscribe the DUT/SUT
ILoad will not over-subscribe the DUT/SUT in this test
Burst Size - The burst size defines the number of frames
back-to-back at the minimum legal IFG [4] before
transmission to receive frames. Burst sizes SHOULD vary between 1
and 930 frames. A burst size of 1 will simulate constant
[1].
Addresses per port - Represents the number of addresses which
being tested for each port. Number of addresses SHOULD be
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended value is 1.
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
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5.4.3
Ports do not send and receive test frames simultaneously. As
consequence, there should be no collisions unless the DUT
misforwarding frames, generating flooded or Spanning-Tree
or is enabling some flow control mechanism. Ports used for
test are either transmitting or receiving, but not both.
ports which are transmitting send test frames destined
addresses corresponding to each of the ports receiving.
creates a unidirectional mesh of traffic
All ports on the tester MUST transmit test frames either in
Frame Based or Time Based mode (Appendix B). All ports
start transmitting their frames within 1% of the trial duration
For a trial duration of 30 seconds, all ports SHOULD have
transmitting frames with 300 milliseconds of each other
Each transmitting port in the test MUST send frames to
receiving ports in a round robin type fashion. The sequence
addresses MUST NOT change when congestion control is applied
The following table shows how each port in a test MUST
test frames to all other ports in the test. In this 8
example, port 1 through 4 are transmitting and ports 5 through 8
are receiving; each with 1 address per port
Source Port, then Destination Ports (in order of transmission
Port #1 5 6 7 8 5 6...
Port #2 6 7 8 5 6 7...
Port #3 7 8 5 6 7 8...
Port #4 8 5 6 7 8 5...
As shown in the table, there is an equal distribution
destination addresses for each transmit opportunity. This
the test balanced so that one destination port is not
by the test algorithm and all receiving ports are equally
fully loaded throughout the test. Not following this
exactly will product inconsistent results
For tests using multiple addresses per port, the actual
destinations are the same as described above and the
source/destination address pairs SHOULD be chosen randomly
exercise the DUT/SUT's ability to perform address lookups
For every address, the testing device MUST send learning frames
allow the DUT/SUT to load its address tables properly.
address table's aging time SHOULD be set sufficiently longer
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RFC 2889 LAN Switch Benchmarking Methodology August 2000
the learning time and trial duration time combined. If
address table ages out during the test, the results will show
lower performing DUT/SUT
To measure the DUT/SUT's ability to switch traffic
performing many different address lookups, the number of
per port MAY be increased in a series of tests
5.4.4
Each receiving port MUST categorize, then count the frames
one of two groups
1.) Received Frames: received frames MUST have the
destination MAC address and SHOULD match a signature field
2.) Flood count [2].
Any frame originating from the DUT/SUT MUST not be counted as
received frame. Frames originating from the DUT/SUT MAY be
as flooded frames or not counted at all
Frame loss rate of the DUT/SUT SHOULD be reported as defined
section 26.3 [3] with the following notes: Frame loss rate SHOULD
measured at the end of the trial duration. The term "rate", for
measurement only, does not imply the units in the fashion of "
second."
5.4.4.1
Throughput measurement is defined in section 26.1 [3]. A
algorithm is employed to find the maximum Oload [2] with a zero
loss rate [1]. The algorithm MUST adjust Iload to find
throughput
5.4.4.2 Forwarding
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the
of test frames per second that the device is observed to
forward to the correct destination interface in response to
specified Oload. The Oload MUST also be cited
Forwarding rate at maximum offered load (FRMOL) MUST be reported
the number of test frames per second that a device can
transmit to the correct destination interface in response to the
as defined in section 3.6 [2]. The MOL MUST also be cited
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RFC 2889 LAN Switch Benchmarking Methodology August 2000
Maximum forwarding rate (MFR) MUST be reported as the
forwarding rate of a DUT/SUT taken from an iterative set
forwarding rate measurements. The iterative set of forwarding
measurements are made by adjusting Iload. The Oload applied to
device MUST also be cited
5.4.5 Reporting
The results for these tests SHOULD be reported in the form of
graph. The x coordinate SHOULD be the frame size, the y
SHOULD be the test results. There SHOULD be at least two lines
the graph, one plotting the theoretical and one plotting the
results
To measure the DUT/SUT's ability to switch traffic while
many different address lookups, the number of addresses per port
be increased in a series of tests
5.5 Congestion
5.5.1
To determine how a DUT handles congestion. Does the device
congestion control and does congestion on one port affect
uncongested port. This procedure determines if Head of Line
and/or Backpressure are present
5.5.2 Setup
The following parameters MUST be defined. Each variable
configured with the following considerations
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9 [3]. The four
bytes are included in the frame size specified
Interframe Gap (IFG) - The IFG between frames inside a burst
be at the minimum specified by the standard (9.6 us for 10
Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for 1
Ethernet) of the medium being tested
Duplex mode - Half duplex or full duplex
Addresses per port - Represents the number of addresses which
being tested for each port. Number of addresses SHOULD be
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended value is 1.
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RFC 2889 LAN Switch Benchmarking Methodology August 2000
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
5.5.3
This test MUST consist of a multiple of four ports with the same MOL
Four ports are REQUIRED and MAY be expanded to fully utilize
DUT/SUT in increments of four. Each group of four will contain
test block with two of the ports as source transmitters and two
the ports as receivers. The diagram below depicts the flow of
between the switch ports
+----------+ 50 % MOL +-------------+
| | ------------------------> | |
| | 50 % MOL | uncongested |
| | --------- | |
+----------+ \ +-------------+
\
\
\
+----------+ \ +-------------+
| | ---------> | |
| | 100 % MOL | congested |
| | ------------------------> | |
+----------+ +-------------+
Both source transmitters MUST transmit the exact number of
frames. The first source MUST transmit test frames at the MOL
the destination address of the two receive ports in an
order. The first test frame to the uncongested receive port,
test frame to the congested receive port, then repeat. The
source transmitter MUST transmit test frames at the MOL only to
congested receive port
Both receive ports SHOULD distinguish between test frames
from the source ports and frames originating from the DUT/SUT.
test frames from the source ports SHOULD be counted
The uncongested receive port should be receiving at a rate of
the MOL. The number of test frames received on the uncongested
SHOULD be 50% of the test frames transmitted by the first
transmitter. The congested receive port should be receiving at
MOL. The number of test frames received on the congested port
be between 100% and 150% of the test frames transmitted by one
transmitter
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Test frames destined to uncongested ports in a switch device
not be dropped due to other ports being congested, even if the
is sending to both the congested and uncongested ports
5.5.4
Any frame received which does not have the correct
address MUST not be counted as a received frame and SHOULD be
as part of a flood count
Any frame originating from the DUT/SUT MUST not be counted as
received frame. Frames originating from the DUT/SUT MAY be
as flooded frames or not counted at all
Frame loss rate of the DUT/SUT's congested and uncongested ports
be reported as defined in section 26.3 [3] with the following notes
Frame loss rate SHOULD be measured at the end of the trial duration
The term "rate", for this measurement only, does not imply the
in the fashion of "per second."
Offered Load to the DUT/SUT MUST be reported as the number of
frames per second that the DUT/SUT observed to accept. This may
different that the MOL
Forwarding rate (FR) of the DUT/SUT's congested and uncongested
MUST be reported as the number of test frames per second that
device is observed to successfully transmit to the
destination interface in response to a specified offered load.
offered load MUST also be cited
5.5.5 Reporting
This test MUST report the frame lost rate at the uncongested port
the forwarding rate (at 50% offered load) at the uncongested port
and the frame lost rate at the congested port. This test MAY
the frame counts transmitted and frame counts received by
DUT/SUT
5.5.5.1
If there is frame loss at the uncongested port, "Head of Line
blocking is present. The DUT cannot forward the amount of traffic
the congested port and as a result it is also losing frames
to the uncongested port
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5.5.5.2 Back
If there is no frame loss on the congested port, then backpressure
present. It should be noted that this test expects the overall
to the congested port to be greater than 100%. Therefore if the
is greater than 100% and no frame loss is detected, then the DUT
be implementing a flow control mechanism. The type of flow
mechanism used is beyond the scope of this memo
It should be noted that some DUTs may not be able to handle the 100%
load presented at the input port. In this case, there may be
loss reported at the uncongested port which is due to the load at
input port rather than the congested port's load
If the uncongested frame loss is reported as zero, but the
forwarding rate is less than 7440 (for 10Mbps Ethernet), then
may be an indication of congestion control being enforced by the DUT
In this case, the congestion control is affecting the throughput
the uncongested port
If no congestion control is detected, the expected percentage
loss for the congested port is 33% at 150% overload. It is
100% load from 1 port, and 50% from another, and can only get 100%
possible throughput, therefore having a frame loss rate of 33%
(150%-50%/150%).
5.6 Forward Pressure and Maximum Forwarding
5.6.1
The Forward Pressure test overloads a DUT/SUT port and measures
output for forward pressure [2]. If the DUT/SUT transmits
with an interframe gap less than 96 bits (section 4.2.3.2.2 [4]),
then forward pressure is detected
The objective of the Maximum Forwarding Rate test is to measure
peak value of the Forwarding Rate when the Offered Load is
between the throughput [1] and the Maximum Offered Load [2].
5.6.2 Setup
The following parameters MUST be defined. Each variable
configured with the following considerations
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9 [3]. The four
bytes are included in the frame size specified
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Duplex mode - Half duplex or full duplex
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
Step Size - The minimum incremental resolution that the Iload
be incremented in frames per second. The smaller the step size
the more accurate the measurement and the more
required. As the Iload approaches the MOL, the minimum step
will increase because of gap resolution on the testing device
5.6.3
5.6.3.1 Maximum forwarding
If the Throughput [1] and the MOL [2] are the same, then MFR [2]
equal to the MOL [2].
This test MUST at a minimum be performed in a two-port
as described below. Learning frames MUST be sent to allow
DUT/SUT to update its address tables properly
Test frames are transmitted to the first port (port 1) of the DUT/
at the Iload. The FR [2] on the second port (port 2) of the DUT/
is measured. The Iload is incremented for each Step Size to find
MFR. The algorithm for the test is as follows
MOL = ... frames/sec; {Maximum Offered Load
MFR := 0 frames/sec; {Maximum Forwarding Rate
ILOAD := starting throughput in frames/sec; {offered load
STEP := ... frames/sec; {Step Size
ILOAD := ILOAD - STEP
ILOAD := ILOAD +
IF (ILOAD > MOL)
ILOAD :=
AddressLearning; {Port 2 broadcasts with its source address
Transmit(ILOAD); {Port 1 sends frames to Port 2 at Offered load
IF (Port 2 Forwarding Rate > MFR)
MFR := Port 2 Forwarding Rate; {A higher value than before
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WHILE (ILOAD < MOL); {ILOAD has reached the MOL value
5.6.3.2 Minimum Interframe
The Minimum Interframe gap test SHOULD, at a minimum, be performed
a two-port configuration as described below. Learning frames MUST
sent to allow the DUT/SUT to update its address tables properly
Test frames SHOULD be transmitted to the first port (port 1) of
DUT/SUT with an interframe gap of 88 bits. This will apply
pressure to the DUT/SUT and overload it at a rate of one byte
frame. The test frames MUST be constructed with a source address
port 1 and a destination address of port 2.
The FR on the second port (port 2) of the DUT/SUT is measured.
measured Forwarding Rate should not exceed the medium's
theoretical utilization (MOL).
5.6.4
Port 2 MUST categorize, then count the frames into one of two groups
1.) Received Frames: received frames MUST have the
destination MAC address and SHOULD match a signature field
2.) Flood count [2].
Any frame originating from the DUT/SUT MUST not be counted as
received frame. Frames originating from the DUT/SUT MAY be
as flooded frames or not counted at all
5.6.5 Reporting
MFR MUST be reported as the highest forwarding rate of a DUT/
taken from an iterative set of forwarding rate measurements.
Iload applied to the device MUST also be cited
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the
of frames per second that the device is observed to
transmit to the correct destination interface in response to
specified Oload. The Iload MUST be cited and the Oload MAY
recorded
If the FR exceeds the MOL during the Minimum Interframe gap test
this MUST be highlighted with the expression "Forward
detected".
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5.7 Address Caching
5.7.1
To determine the address caching capacity of a LAN switching
as defined in RFC 2285, section 3.8.1 [2].
5.7.2 Setup
The following parameters MUST be defined. Each variable
configured with the following considerations
Age Time - The maximum time that a DUT/SUT will keep a
address in its forwarding table
Addresses Learning Rate - The rate at which new addresses
offered to the DUT/SUT to be learned. The rate at which
learning frames are offered may have to be adjusted to be as
as 50 frames per second or even less, to guarantee
learning
Initial Addresses - The initial number of addresses to start
test with. The number MUST be between 1 and the maximum
supported by the implementation
5.7.3
The aging time of the DUT/SUT MUST be known. The aging time MUST
longer than the time necessary to produce frames at the
rate. If a low frame rate is used for the test, then it may
possible that sending a large amount of frames may actually
longer than the aging time
This test MUST at a minimum be performed in a three-
configuration described below. The test MAY be expanded to
utilized the DUT/SUT in increments of two or three ports.
increment of two would include an additional Learning port and
port. An increment of three would include an additional
port, Test port, and Monitoring port
The Learning port (Lport) transmits learning frames to the DUT/
with varying source addresses and a fixed destination
corresponding to the address of the device connected to the Test
(Tport) of the DUT/SUT. By receiving frames with varying
addresses, the DUT/SUT should learn these new addresses. The
addresses MAY be in sequential order
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The Test port (Tport) of the DUT/SUT acts as the receiving port
the learning frames. Test frames will be transmitted back to
addresses learned on the Learning port. The algorithm for this
explained below
The Monitoring port (Mport) on the DUT/SUT acts as a monitoring
to listen for flooded or mis-forwarded frames. If the test
multiple broadcast domains (VLANs), each broadcast domain REQUIRES
Monitoring port
It is highly recommended that SNMP, Spanning Tree, and any
frames originating from the DUT/SUT be disabled when running
test. If such protocols cannot be turned off, the flood count
be modified only to count test frame originating from Lport and
NOT count frames originating from the DUT/SUT
The algorithm for the test is as follows
AGE = ...; {value greater that DUT aging time
MAX = ...; {maximum address support by implementation
LOW := 0; {Highest passed valve
HIGH := MAX; {Lowest failed value
N := ...; {user specified initial starting point
PAUSE(AGE); {Age out any learned addresses
AddressLearning(TPort); {broadcast a frame with its
Address and broadcast destination
AddressLearning(LPort); {N frames with varying source
to Test Port
Transmit(TPort); {N frames with varying destination
corresponding to Learning Port
IF (MPort receive frame != 0)
(LPort receive frames < TPort transmit)
BEGIN {Address Table of DUT/SUT was full
HIGH := N
BEGIN {Address Table of DUT/SUT was NOT full
LOW := N
N := LOW + (HIGH - LOW)/2;
END WHILE (HIGH - LOW >= 2);
END {Value of N equals number of addresses supported by DUT/SUT
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Using a binary search approach, the test targets the exact number
addresses supported per port with consistent test iterations. Due
the aging time of DUT/SUT address tables, each iteration may
some time during the waiting period for the addresses to clear.
possible, configure the DUT/SUT for a low value for the aging time
Once the high and low values of N meet, then the threshold of
handling has been found
5.7.4
Whether the offered addresses per port was successful
without flooding
5.7.5 Reporting
After the test is run, results for each iteration SHOULD be
in a table to include
The number of addresses used for each test iteration (varied).
The intended load used for each test iteration (fixed).
Number of test frames that were offered to Tport of the DUT/SUT
This SHOULD match the number of addresses used for the
iteration. Test frames are the frames sent with
destination addresses to confirm that the DUT/SUT has learned
of the addresses for each test iteration
The flood count on Tport during the test portion of each test.
the number is non-zero, this is an indication of the DUT/
flooding a frame in which the destination address is not in
address table
The number of frames correctly forwarded to test Lport during
test portion of the test. Received frames MUST have the
destination MAC address and SHOULD match a signature field. For
passing test iteration, this number should be equal to the
of frames transmitted by Tport
The flood count on Lport during the test portion of each test.
the number is non-zero, this is an indication of the DUT/
flooding a frame in which the destination address is not in
address table
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The flood count on Mport. If the value is not zero, then
indicates that for that test iteration, the DUT/SUT could
determine the proper destination port for that many frames.
other words, the DUT/SUT flooded the frame to all ports since
address table was full
5.8 Address Learning
5.8.1
To determine the rate of address learning of a LAN switching device
5.8.2 Setup
The following parameters MUST be defined. Each variable
configured with the following considerations
Age Time - The maximum time that a DUT/SUT will keep a
address in its forwarding table
Initial Addresses Learning Rate - The starting rate at which
addresses are offered to the DUT/SUT to be learned
Number of Addresses - The number of addresses that the DUT/
must learn. The number MUST be between 1 and the maximum
supported by the implementation. It is recommended no to
the address caching capacity found in section 5.9
5.8.3
The aging time of the DUT/SUT MUST be known. The aging time MUST
longer than the time necessary to produce frames at the
rate. If a low frame rate is used for the test, then it may
possible that sending a large amount of frames may actually
longer than the aging time
This test MUST at a minimum be performed in a three-
configuration in section 5.9.3. The test MAY be expanded to
utilized the DUT/SUT in increments of two or three ports.
increment of two would include an additional Learning port and
port. An increment of three would include an additional
port, Test port, and Monitoring port
An algorithm similar to the one used to determine address
capacity can be used to determine the address learning rate.
test iterates the rate at which address learning frames are
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by the test device connected to the DUT/SUT. It is recommended
set the number of addresses offered to the DUT/SUT in this test
the maximum caching capacity
The address learning rate might be determined for different
of addresses but in each test run, the number MUST remain
and SHOULD be equal to or less than the maximum address
capacity
5.8.4
Whether the offered addresses per port were successful
without flooding at the offered learning rate
5.8.5 Reporting
After the test is run, results for each iteration SHOULD be
in a table
The number of addresses used for each test iteration (fixed).
The intended load used for each test iteration (varied).
Number of test frames that were transmitted by Tport. This
match the number of addresses used for the test iteration.
frames are the frames sent with varying destination addresses
confirm that the DUT/SUT has learned all of the addresses for
test iteration
The flood count on Tport during the test portion of each test.
the number is non-zero, this is an indication of the DUT/
flooding a frame in which the destination address is not in
address table
The number of frames correctly forwarded to test Lport during
test portion of the test. Received frames MUST have the
destination MAC address and SHOULD match a signature field. For
passing test iteration, this number should be equal to the
of frames transmitted by Tport
The flood count on Lport during the test portion of each test.
the number is non-zero, this is an indication of the DUT/
flooding a frame in which the destination address is not in
address table
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The flood count on Mport. If the value is not zero, then
indicates that for that test iteration, the DUT/SUT could
determine the proper destination port for that many frames.
other words, the DUT/SUT flooded the frame to all ports since
address table was full
5.9 Errored frames
5.9.1
The objective of the Errored frames filtering test is to
the behavior of the DUT under error or abnormal frame conditions
The results of the test indicate if the DUT/SUT filters the errors
or simply propagates the errored frames along to the destination
5.9.2 Setup
The following parameters MUST be defined. Each variable
configured with the following considerations
ILoad - Intended Load per port is expressed in a percentage of
medium's maximum theoretical load possible. The
transmitted frame per second is dependent upon half duplex or
duplex operation. The test SHOULD be run multiple times with
different load per port in each case
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
5.9.3
Each of the illegal frames for Ethernet MUST be checked
Oversize - The DUT/SUT MAY filter frames larger than 1518 bytes
being propagated through the DUT/SUT section 4.2.4.2.1 [4].
Oversized frames transmitted to the DUT/SUT should not be forwarded
DUT/SUT supporting tagged Frames MAY forward frames up to
including 1522 bytes long (section 4.2.4.2.1 [5]).
Undersize - The DUT/SUT MUST filter frames less than 64 bytes
being propagated through the DUT/SUT (section 4.2.4.2.2 [4]).
Undersized frames (or collision fragments) received by the DUT/
must not be forwarded
CRC Errors - The DUT/SUT MUST filter frames that fail the Frame
Sequence Validation (section 4.2.4.1.2 [4]) from being
through the DUT/SUT. Frames with an invalid CRC transmitted to
DUT/SUT should not be forwarded
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Dribble Bit Errors - The DUT/SUT MUST correct and forward
containing dribbling bits. Frames transmitted to the DUT/SUT that
not end in an octet boundary but contain a valid frame check
MUST be accepted by the DUT/SUT (section 4.2.4.2.1 [4]) and
to the correct receive port with the frame ending in an
boundary (section 3.4 [4]).
Alignment Errors - The DUT/SUT MUST filter frames that fail the
Check Sequence Validation AND do not end in an octet boundary.
is a combination of a CRC error and a Dribble Bit error. When
errors are occurring in the same frame, the DUT/SUT MUST
the CRC error takes precedence and filters the frame (
4.2.4.1.2 [4]) from being propagated
5.9.5 Reporting
For each of the error conditions in section 5.6.3, a "pass" or "fail
MUST be reported. Actual frame counts MAY be reported for
purposes
5.10 Broadcast frame Forwarding and
5.10.1
The objective of the Broadcast Frame Forwarding and Latency Test
to determine the throughput and latency of the DUT when
broadcast traffic. The ability to forward broadcast frames
depend upon a specific function built into the device for
purpose. It is therefore necessary to determine the ability
DUT/SUT to handle broadcast frames, since there may be many
ways of implementing such a function
5.10.2 Setup
The following parameters MUST be defined. Each variable
configured with the following considerations
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9 [3]. The four
bytes are included in the frame size specified
Duplex mode - Half duplex or full duplex
ILoad - Intended Load per port is expressed in a percentage of
medium's maximum theoretical load, regardless of
orientation or duplex mode. Certain test configurations
theoretically over-subscribe the DUT/SUT
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ILoad will not over-subscribe the DUT/SUT in this test
Trial Duration - The recommended Trial Duration is 30 seconds
Trial duration SHOULD be adjustable between 1 and 300 seconds
5.10.3
For this test, there are two parts to be run
Broadcast Frame Throughput - This portion of the test uses a
source test port to transmit test frames with a broadcast
using the frame specified in RFC 2544 [3]. Selected receive
then measure the forwarding rate and Frame loss rate
Broadcast Frame Latency - This test uses the same setup as
Broadcast Frame throughput, but instead of a large stream of
frames being sent, only one test frame is sent and the latency
each of the receive ports are measured in seconds
5.10.4
Frame loss rate of the DUT/SUT SHOULD be reported as defined
section 26.3 [3] with the following notes: Frame loss rate SHOULD
measured at the end of the trial duration. The term "rate", for
measurement only, does not imply the units in the fashion of "
second."
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the
of test frames per second that the device is observed to
forward to the correct destination interface in response to
specified Oload. The Oload MUST also be cited
5.10.5 Reporting
The results for these tests SHOULD be reported in the form of
graph. The x coordinate SHOULD be the frame size, the y
SHOULD be the test results. There SHOULD be at least two lines
the graph, one plotting the theoretical and one plotting the
results
To measure the DUT/SUT's ability to switch traffic while
many different address lookups, the number of addresses per port
be increased in a series of tests
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6. Security
As this document is solely for the purpose of providing
methodology and describes neither a protocol nor a protocol'
implementation, there are no security considerations associated
this document
7.
[1] Bradner, S., Editor, "Benchmarking Terminology for
Interconnection Devices", RFC 1242, July 1991.
[2] Mandeville, R., "Benchmarking Terminology for LAN
Devices", RFC 2285, February 1998.
[3] Bradner, S. and J. McQuaid, "Benchmarking Methodology
Network Interconnect Devices", RFC 2544, March 1999.
[4] ANSI/IEEE, "CSMA/CD Access Method and Physical
Specifications," ISO/IEC 8802-3, ISBN 0-7381-0330-6, 1998.
[5] IEEE Draft, "Frame Extensions for Virtual Bridged Local
Networks (VLAN) Tagging on 802.3 Networks", 802.3ac/D3.1,
1998.
8. Authors'
Robert
CQOS Inc
21
Irvine, CA 92618
Phone: +1 (949) 400-4444
EMail: bob@cqos.
Jerry
Spirent
26750 Agoura
Calabasas, CA 91302
Phone: + 1 818 676 2300
EMail: jerry_perser@netcomsystems.
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Appendix A:
A.1 Calculating the InterBurst
IBG is defined in RFC 2285 [2] as the interval between two bursts
To achieve a desired load, the following Input Parameter need to
defined
LENGTH - Frame size in bytes including the CRC
LOAD - The intended load in percent. Range is 0 to 100.
BURST - The number of frames in the burst (integer value).
SPEED - media's speed in bits/
Ethernet is 10,000,000 bits/
Fast Ethernet is 100,000,000 bits/
Gigabit Ethernet is 1,000,000,000 bits/
IFG - A constant 96 bits for the minimum interframe gap
The IBG (in seconds) can be calculated
[(100/LOAD - 1) * BURST * (IFG + 64 + 8*LENGTH)] +
IBG = -----------------------------------------------------------
A.2 Calculating the Number of Bursts for the Trial
The number of bursts for the trial duration is rounded up to
nearest integer number. The follow Input Parameter need to
defined
LENGTH - Frame size in bytes including the CRC
BURST - The number of frames in the burst (integer value).
SPEED - media's speed in bits/
Ethernet is 10,000,000 bits/
Fast Ethernet is 100,000,000 bits/
Gigabit Ethernet is 1,000,000,000 bits/
IFG - A constant 96 bits for the minimum interframe gap
IBG - Found in the above
DURATION - Trial duration in seconds
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An intermediate number of the Burst duration needs to be
first
TXTIME = -----------------------------------------
Number of Burst for the Trial Duration (rounded up):
#OFBURSTS = --------------
(TXTIME + IBG
Example
LENGTH = 64 bytes per
LOAD = 100 % offered
BURST = 24 frames per
SPEED = 10 Mbits/sec (Ethernet
DURATION = 10 seconds
IBG = 1612.8
TXTIME = 1603.2
#OFBURSTS = 3110
Appendix B: Generating Offered
In testing, the traffic generator is configured with the
(Intended Load) and measures the Oload (Offered Load). If
DUT/SUT applies congestion control, then the Iload and the Oload
not the same value. The question arises, how to generate the Oload
This appendix will describe two different methods
The unit of measurement for Oload is bits per second. The
methods described here will hold one unit constant and let
DUT/SUT vary the other unit. The traffic generator SHOULD
which method it uses
B.1 Frame Based
Frame Based Load holds the number of bits constant. The
Duration will vary based upon congestion control. Advantage
implementation is a simple state machine (or loop). The
is that Oload needs to be measured independently
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All ports on the traffic generator MUST transmit the exact number
test frames. The exact number of test frames is found by
the Iload of the port by the Trial Duration. All ports MAY
transmit the same number of frames if their Iload is not the same
An example would be the Partially meshed many-to-one test
All ports SHOULD start transmitting their frames within 1% of
trial duration. For a trial duration of 30 seconds, all ports
have started transmitting frames within 300 milliseconds of
other
The reported Oload SHOULD be the average during the Trial Duration
If the traffic generator continues to transmit after the
Duration due to congestion control, Oload MAY be averaged over
entire transmit time. Oload for the DUT/SUT MUST be the aggregate
all the Oloads per port. Oload per port MAY be reported
B.2 Time Based
Time based load holds the Trial Duration constant, while allowing
number of octets transmitted to vary. Advantages are an
Trial Duration and integrated Oload 