draft-ietf-bmwg-mswitch-00.txt   draft-ietf-bmwg-mswitch-01.txt 
Network Working Group R. Mandeville Network Working Group R. Mandeville
Internet-Draft European Network Laboratories Internet-Draft European Network Laboratories
Expiration Date: February 1999 J. Keene Expiration Date: November 1999 J. Perser
Netcom Systems Netcom Systems
August 1998 May 1999
Benchmarking Methodology for LAN Switching Devices Benchmarking Methodology for LAN Switching Devices
<draft-ietf-bmwg-mswitch-00.txt> <draft-ietf-bmwg-mswitch-01.txt>
Status of this Memo Status of this Memo
This document is an Internet-Draft. Internet-Drafts are working This document is an Internet-Draft and is in full conformance with
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Abstract Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Test setup . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. Frame formats and sizes . . . . . . . . . . . . . . . . . . . . 3
5. Benchmarking Tests . . . . . . . . . . . . . . . . . . . . . . 4
5.1 Fully meshed throughput, frame loss and forwarding rates . . 4
5.2 Partially meshed overloading . . . . . . . . . . . . . . . . 7
5.3 Head of line blocking . . . . . . . . . . . . . . . . . . . . 10
5.4 Partially meshed multiple devices . . . . . . . . . . . . . . 13
5.5 Multiple streams of unidirectional traffic . . . . . . . . . 15
5.6 Filter illegal frames . . . . . . . . . . . . . . . . . . . . 18
5.7 Broadcast frame handling and latency . . . . . . . . . . . . 20
5.8 Maximum forwarding rate and minimum interframe gap . . . . . 21
5.9 Address caching capacity . . . . . . . . . . . . . . . . . . 23
5.10 Address learning rate . . . . . . . . . . . . . . . . . . . . 26
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 28
7. Authors' Address . . . . . . . . . . . . . . . . . . . . . . . 28
Appendix A: Formulas . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction
This document is intended to provide methodology for the benchmarking This document is intended to provide methodology for the benchmarking
of local area network (LAN) switching devices. It extends the of local area network (LAN) switching devices. It extends the
methodology already defined for benchmarking network interconnecting methodology already defined for benchmarking network interconnecting
devices in RFC 1944 to switching devices. devices in RFC 2544 to switching devices.
This RFC primarily deals with devices which switch frames at the This RFC primarily deals with devices which switch frames at the
Medium Access Control (MAC) layer. It provides a methodology for Medium Access Control (MAC) layer. It provides a methodology for
benchmarking switching devices, forwarding performance, congestion benchmarking switching devices, forwarding performance, congestion
control, latency, address handling and filtering. In addition to control, latency, address handling and filtering. In addition to
defining the tests, this document also describes specific formats for defining the tests, this document also describes specific formats for
reporting the results of the tests. reporting the results of the tests.
1. Introduction
This document defines a specific set of tests to measure and report
the performance characteristics of network switching devices.
A previous document, "Benchmarking Terminology for LAN Switching A previous document, "Benchmarking Terminology for LAN Switching
Devices" (RFC 2285), defined many of the terms that are used in this Devices" (RFC 2285), defined many of the terms that are used in this
document. The terminology document SHOULD be consulted before document. The terminology document SHOULD be consulted before
attempting to make use of this document. attempting to make use of this document.
2. Requirements 2. Requirements
The following RFCs SHOULD be consulted before attempting to make use The following RFCs SHOULD be consulted before attempting to make use
of this document: of this document:
* RFC 1242 "Benchmarking Terminology for Network Interconnect * RFC 1242 "Benchmarking Terminology for Network Interconnect
Devices" Devices"
* RFC 1944 "Benchmarking Methodology for Network Interconnect
Devices"
* RFC 2285 "Benchmarking Terminology for LAN Switching Devices" * RFC 2285 "Benchmarking Terminology for LAN Switching Devices"
* RFC 2544 "Benchmarking Methodology for Network Interconnect
Devices"
For the sake of clarity and continuity, this RFC adopts the template For the sake of clarity and continuity, this RFC adopts the template
for benchmarking tests set out in Section 26 of RFC 1944. for benchmarking tests set out in Section 26 of RFC 2544.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in
this document are to be interpreted as described in RFC 2119. this document are to be interpreted as described in RFC 2119.
3. Test setup 3. Test setup
This document extends the general test setup described in section 6 This document extends the general test setup described in section 6
of RFC 1944 to the benchmarking of LAN switching devices. RFC 1944 of RFC 2544 to the benchmarking of LAN switching devices. RFC 2544
primarily describes non-meshed traffic where input and output primarily describes non-meshed traffic where input and output
interfaces are grouped in mutually exclusive sending and interfaces are grouped in mutually exclusive sending and receiving
receiving pairs. In fully meshed traffic, each interface of a pairs. In fully meshed traffic, each interface of a DUT/SUT is set
DUT/SUT is set up to both receive and transmit frames to all up to both receive and transmit frames to all the other interfaces
the other interfaces under test. under test.
Prior to each test run, the DUT/SUT MUST learn the MAC addresses used Prior to each test run, the DUT/SUT MUST learn the MAC addresses used
in in the test and the address learning SHOULD be verified. Addresses
the test and the address learning MUST be verified to avoid flooded not learned will be forwarded as flooded frames and reduce the amount
frames being counted as correctly received frames. The forwarding of correctly forwarded frames. The rate at which address learning
rate, namely the rate at which address learning frames are offered frames are offered may have to be adjusted to be as low as 50 frames
may per second or even less, to guarantee successful learning. The
have to be adjusted to be as low as 50 frames per second or even DUT/SUT address aging time SHOULD be configured to be greater than
less, the period of the learning phase of the test plus the test duration
to guarantee successful learning. The DUT/SUT address aging time plus any configuration time required by the testing device.
SHOULD be Addresses SHOULD NOT age out until the test duration is completed.
configured to be greater than the period between the learning phase More than one learning trial may be needed for the association of the
of address to the port to occur.
the test and the test run; in non-meshed and partially meshed tests,
the aging time SHOULD at a minimum be set to at least the length of
the test period. More than one trial may be needed for the
association
of the address to the port to occur.
If a DUT/SUT uses a hashing algorithm with address learning, the If a DUT/SUT uses a hashing algorithm with address learning, the
DUT/SUT may not learn the necessary addresses to perform the tests. DUT/SUT may not learn the necessary addresses to perform the tests.
The format of the MAC addresses MUST be adjustable so that the The format of the MAC addresses MUST be adjustable so that the
address address mapping may be re-arranged to make a DUT/SUT learn addresses
mapping may be re-arranged to make a DUT/SUT learn addresses
without confusion. without confusion.
It is recommended that SNMP and Spanning Tree be disabled when bench- It is recommended that SNMP and Spanning Tree be disabled when bench-
marking switching devices unless investigating overhead behavior. If marking switching devices unless investigating overhead behavior. If
such protocols cannot be turned off, it is recommended that the such protocols cannot be turned off, it is recommended that the
levels of offered load be reduced (less than 100%) to allow for levels of offered load be reduced (less than 100%) to allow for
the additional management frames. the additional management frames.
4. Frame formats and sizes 4. Frame formats and sizes
For frame formats and sizes, refer to RFC 1944, sections 8 and 9 and The frame format is defined in RFC 2544 section 8 and MUST contain a
Appendix C. unique signature field located in the UDP DATA area of the Test Frame
(see Appendix C of RFC 2544). The purpose of the signature field is
filter out frames that are not part of the offered load.
There are three frame formats for layer 2 Ethernet switches: The signature field MUST be unique enough to identify the frames not
originating from the DUT/SUT. The signature field SHOULD be located
after byte 56 (ISO/IEC 8802-3 collision window) or at the end of the
frame. The length, contents and method of detection is not defined
in this memo.
The signature field MAY have a unique identifier per port. This
would filter out misforwarded frames. It is possible for a DUT/SUT
to strip off the MAC layer, send it through its switching matrix,
and transmit it out with the correct destination MAC address but the
wrong payload.
For frame sizes, refer to RFC 2544, section 9.
There are three possible frame formats for layer 2 Ethernet switches:
standard MAC Ethernet frames, standard MAC Ethernet frames standard MAC Ethernet frames, standard MAC Ethernet frames
with vendor-specific tags added to them, and IEEE 802.3ab with vendor-specific tags added to them, and IEEE 802.3ac
frames tagged to accommodate 802.3p,q. The two types of tagged frames tagged to accommodate 802.3p&q. The two types of tagged
frames may exceed the standard maximum length frame of 1518 bytes, frames may exceed the standard maximum length frame of 1518 bytes,
and and may not be accepted by the interface controllers of some
may not be accepted by the interface controllers of some DUT/SUTs. DUT/SUTs. It is recommended to check the compatibility of the DUT/SUT
It is recommended to check the compatibility of the DUT/SUT
with tagged frames before testing. with tagged frames before testing.
Devices switching tagged frames of over 1518 bytes will have a lower Devices switching tagged frames of over 1518 bytes will have a lower
maximum forwarding rate than standard untagged frames. maximum forwarding rate than standard untagged frames.
5. Benchmarking Tests 5. Benchmarking Tests
The following tests offer objectives, procedures, and reporting The following tests offer objectives, procedures, and reporting
formats for benchmarking LAN switching devices. formats for benchmarking LAN switching devices.
5.1 Fully meshed throughput, frame loss and forwarding rates 5.1 Fully meshed throughput, frame loss and forwarding rates
5.2 Partially meshed overloading
5.3 Head of line blocking
5.4 Partially meshed multiple devices
5.5 Multiple streams of unidirectional traffic
5.6 Filter illegal frames
5.7 Broadcast frame handling and latency
5.8 Maximum forwarding rate and minimum interframe gap
5.9 Address caching capacity
5.10 Address learning rate
5.1 Fully meshed throughput, frame loss and forwarding rates
Objective: 5.1.1 Objective
To determine the throughput, frame loss and forwarding rates of To determine the throughput, frame loss and forwarding rates of
DUT/SUTs DUT/SUTs offered fully meshed traffic as defined in RFC 2285.
offered fully meshed traffic as defined in RFC 2285.
Procedure: 5.1.2 Setup Parameters
RFC 2285 points out that when offering bursty meshed traffic, the When offering bursty full meshed traffic, the following parameters
variables which MUST be defined are frame size, bust size, MUST be defined. Each parameter is configured with the following
interframe gap, interburst gap, and load. Each variable is considerations.
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. The four CRC bytes
are included in the frame size specified.
Interframe Gap (IFG) - The IFG between frames inside a burst Interframe Gap (IFG) - The IFG between frames inside a burst
MUST MUST be at the minimum specified by the standard (9.6 us for
be at the minimum specified by the standard (9.6 us for 10Mbps 10Mbps Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for
Ethernet and 0.96 us for 100Mbps Ethernet). 1 Gbps Ethernet).
Interburst Gap (IBG) - This is the interval between bursts of Interburst Gap (IBG) - This is the interval between bursts of
traffic. Refer to Appendix A, Calculating Interburst Gap, for traffic. Refer to Appendix A Formulas, for the formula used to
the formula used to compute IBG. compute IBG.
Load / Port - The test SHOULD be run multiple times with a Duplex mode - Half duplex or full duplex.
different load per port in each case. The 100% load translates to
a transmit load of 50% for half duplex. This type of test SHOULD
also be run at higher than 100% loads.
In half duplex mode, exactly half of the target load SHOULD be Load / Port - Load per port is expressed in a percentage of the
sent to each of the ports under test. For example, with a 100% medium's maximum intended load possible. The actual transmitted
load of 64-byte frames, the target load for each port under test frame per second is dependent upon half duplex or full duplex
is 7440 frames received per second and 7440 frames transmitted per operation. The test SHOULD be run multiple times with a different
second (for 10Mbps Ethernet). load per port in each case.
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024, In half duplex mode, exactly half of the intended load SHOULD be
1280 and 1518 bytes, per RFC 1944 section 9. transmitted to each of the ports under test. For example, with a
100% load of 64-byte frames, the intended load for each port under
test is 7440 frames received per second and 7440 frames
transmitted per second (for 10Mbps Ethernet).
Burst Size - The burst size defines the number of packets sent In full duplex mode, the entire intended load SHOULD be
transmitted to each of the ports under test. For example, with a
100% load of 64-byte frames, the intended load for each port under
test is 14880 frames received per second and 14880 frames
transmitted per second (for 10Mbps Ethernet).
Burst Size - The burst size defines the number of frames sent
back-to-back at the minimum legal IFG (96 bit times) before back-to-back at the minimum legal IFG (96 bit times) before
pausing transmission to receive frames. Burst sizes pausing transmission to receive frames. Burst sizes
SHOULD vary between 1 and 930 frames. SHOULD vary between 1 and 930 frames. A burst size of 1 will
simulate non-bursty traffic.
To avoid truncating bursts, a burst size SHOULD be an even Addresses per port - Represents the number of addresses which
multiple into 7440. 7440 is the maximum frames per second for half are being tested for each port. Number of addresses SHOULD be a
duplex mode; 14880 is the maximum frames per second for full binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
duplex mode. Refer to Appendix A for a table of recommended burst Recommended values are 1, 16 and 256.
values.
Each port in the test sends frames to all other ports in a round- Test Duration - Test duration SHOULD be between 1 and 300 seconds.
robin type fashion. The following table shows how each port in a test RFC 2285 recommends a duration of at least 10 seconds for each
SHOULD transmit frames to all other ports in the test. In this test.
5.1.3 Procedure
All ports MUST transmit the exact number of frames. All ports SHOULD
start transmitting their frames within 1% of the test duration. For
a test duration of 10 seconds, all ports SHOULD have started
transmitting frames with 100 milliseconds of each other.
Each port in the test MUST send frames to all other ports in a
round robin type fashion. The following table shows how each port in
a test MUST transmit frames to all other ports in the test. In this
example, there are six ports with 1 address per port: example, there are six ports with 1 address per port:
Source Port, then Destination Ports (in order of transmission) Source Port Destination Ports (in order of transmission)
Port #1 2 3 4 5 6 2... Port #1 2 3 4 5 6 2...
Port #2 3 4 5 6 1 3... Port #2 3 4 5 6 1 3...
Port #3 4 5 6 1 2 4... Port #3 4 5 6 1 2 4...
Port #4 5 6 1 2 3 5... Port #4 5 6 1 2 3 5...
Port #5 6 1 2 3 4 6... Port #5 6 1 2 3 4 6...
Port #6 1 2 3 4 5 1... Port #6 1 2 3 4 5 1...
As shown in the table, there is an equal distribution of destination As shown in the table, there is an equal distribution of destination
addresses for each transmit opportunity. This keeps the test balanced addresses for each transmit opportunity. This keeps the test balanced
so that one destination port is not overloaded by the test algorithm so that one destination port is not overloaded by the test algorithm
and all ports are equally and fully loaded throughout the test. For and all ports are equally and fully loaded throughout the test. Not
tests using multiple addresses per port, the actual port destinations following this algorithm exactly will produce inconsistent results.
are the same as described above and the actual source/destination
address
pairs are chosen randomly to exercise the DUT/SUT's ability to
perform
address lookups.
For every address, the testing device sends learning packets to allow For tests using multiple addresses per port, the actual port
the DUT/SUT to load its address tables properly. destinations are the same as described above and the actual
source/destination address pairs SHOULD be chosen randomly to
exercise the DUT/SUT's ability to perform address lookups.
To measure the DUT/SUT's ability to switch traffic while performing For every address, the testing device MUST send learning frames to
many allow the DUT/SUT to update its address tables properly.
different address lookups, the number of addresses per port SHOULD be
increased in a series of tests.
Reporting format: 5.1.4 Measurements
In these tests, a port SHOULD transmit and receive the same amount of Each port should receive the same number of frames that it
packets. Each port MUST count the packets received with a valid transmitted. Each receiving port MUST categorize, then count the
address. frames into one of two groups:
Any packet received which does not have a valid address MUST not be
counted as a received packet and can be counted as part of a flood
count as described in 3.8.3 in RFC 2285.
The results for these tests SHOULD be reported in the form of 1.) Received Frames: received frames MUST have the correct
numerical destination MAC address and SHOULD match a signature field.
data or a graph with text to indicate the data type. The data types
for 2.) Flood count: defined in RFC 2285 3.8.3.
the throughput test and for the frame loss rate test are described in
RFC 1944. Any frame received which does not have the correct destination
address MUST not be counted as a received frame and SHOULD be counted
as part of a flood count.
Any frame originating from the DUT/SUT MUST not be counted as a
received frame. Frames originating from the DUT/SUT MAY be counted
as flooded frames or not counted at all.
Frame loss rate of the DUT/SUT SHOULD be reported as defined in
RFC 2544 section 26.3 with the following notes: Frame loss rate
SHOULD be measured at the end of the test duration. The term "rate",
for this measurement only, does not imply the units in the fashion of
"per seconds."
Throughput measurement is defined in RFC 2544.
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
of of frames per second that the device is observed to successfully
frames per second that the device is observed to successfully transmit to the correct destination interface in response to a
transmit specified offered load. The offered load MUST also be cited.
to the correct destination interface in response to a specified
offered
load. The offered load MUST also be cited.
Forwarding rate at maximum offered load (FRMOL ) SHOULD be reported Forwarding rate at maximum offered load (FRMOL) MUST be reported
as as the number of frames per second that a device can successfully
the number of frames per second that a device can successfully transmit to the correct destination interface in response to the
transmit maximum offered load as defined in RFC 2285, section 3.6. The
to the correct destination interface in response to the maximum maximum offered load MUST also be cited.
offered
load as defined in RFC 2285, section 3.6. The maximum offered load Maximum forwarding rate (MFR) MUST be reported as the highest
MUST forwarding rate of a DUT/SUT taken from an iterative set of
forwarding rate measurements. The load applied to the device MUST
also be cited. also be cited.
Maximum forwarding rate (MFR) SHOULD be reported as the highest 5.1.5 Reporting format
forwarding
rate of a DUT/SUT taken from an iterative set of forwarding rate The results for these tests SHOULD be reported in the form of a
measurements. The load applied to the device MUST also be cited. graph. The x coordinate SHOULD be the frame size, the y coordinate
SHOULD be the test results. There SHOULD be at least two lines on
the graph, one plotting the theoretical and one plotting the test
results.
To measure the DUT/SUT's ability to switch traffic while performing
many different address lookups, the number of addresses per port
MAY be increased in a series of tests.
5. 2 Partially meshed overloading 5. 2 Partially meshed overloading
To be done. 5.2.1 Objective
5. 3 Head-of-line blocking To determine the throughput when transmitting from/to multiple ports
and to/from one port. As with the fully meshed throughput test, this
test is a measure of the capability of the DUT to switch frames
without frame loss. Results of this test can be used to determine
the ability of the DUT to utilize an Ethernet port when switching
traffic from multiple Ethernet ports.
To be done. 5.2.2 Setup Parameters
5.4 Partially Meshed Multiple Devices When offering bursty meshed traffic, the following parameters MUST
be defined. Each parameter is configured with the following
considerations.
To be done. Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
1280 and 1518 bytes, per RFC 2544 section 9. The four CRC bytes
are included in the frame size specified.
5.5 Multiple streams of unidirectional traffic Traffic Direction - Traffic can be generated in one direction, the
reverse direction, or both directions.
To be done. Interframe Gap (IFG) - The IFG between frames inside a burst
MUST be at the minimum specified by the standard (9.6 us for
10Mbps Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for
1 Gbps Ethernet).
5.6 Filter illegal frames Interburst Gap (IBG) - This is the interval between bursts of
traffic. Refer to Appendix A, Calculating Interburst Gap, for
the formula used to compute IBG.
To be done. Duplex mode - Half duplex or full duplex.
5.7 Broadcast frame handling and latency test Load / Port - Load per port is expressed in a percentage of the
medium's maximum intended load possible. The actual transmitted
frame per second is dependent upon half duplex or full duplex
operation. The test SHOULD be run multiple times with a different
load per port in each case.
To be done. In half duplex mode, exactly half of the intended load SHOULD be
transmitted to each of the ports under test. For example, with a
100% load of 64-byte frames, the intended load for each port under
test is 7440 frames received per second and 7440 frames
transmitted per second (for 10Mbps Ethernet).
5.8 Maximum forwarding rate and minimum interframe gap In full duplex mode, the entire intended load SHOULD be
transmitted to each of the ports under test. For example, with a
100% load of 64-byte frames, the intended load for each port under
test is 14880 frames received per second and 14880 frames
transmitted per second (for 10Mbps Ethernet).
To be done. Burst Size - The burst size defines the number of frames sent
back-to-back at the minimum legal IFG (96 bit times) before
pausing transmission to receive frames. Burst sizes
SHOULD vary between 1 and 930 frames. A burst size of 1 will
simulate non-bursty traffic.
5.9 Address Caching Capacity Addresses per port - Represents the number of addresses which
are being tested for each port. Number of addresses SHOULD be a
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended values are 1, 16 and 256.
Objective: Test Duration - Test duration SHOULD be between 1 and 300 seconds.
RFC 2285 recommends a duration of at least 10 seconds for each
test.
To determine the address caching capacity of a LAN switching device 5.2.3 Procedure
as defined in RFC 2285, section 3.8.1.
Procedure: In this test, each transmitting port MUST transmit the exact number
of frames. Depending upon traffic direction, some or all of the
ports will be transmitting.
This test SHOULD at a minimum be performed in a three-port Frames transmitted from the Many Ports MUST be destined to the One
configuration as described below. port. Frames transmitted from the One Port MUST be destined to the
Many ports in a round robin type fashion. See section 5.1.3 for a
description of the round robin fashion.
The first port (port 1) of the testing device is connected to the For tests using multiple addresses per port, the actual port
DUT/SUT destinations are the same as described above and the actual
and is the port from which a testing device sends frames with varying source/destination address pairs SHOULD be chosen randomly to
source addresses and a fixed destination address corresponding to the exercise the DUT/SUT's ability to perform address lookups.
MAC
address of the receiving port. By receiving frames with varying
source
addresses, the DUT/SUT will learn these new addresses from the
sending port
of the test device.
A second port (port 2) of the testing device is connected to the +----------+
DUT/SUT | |
and acts as the receiving port for the address learning frames. This | Many | <--------
port also sends "control" frames back to the addresses learned | | \
on the first port. The algorithm for this is explained below. +----------+ \
\
+----------+ \ +-------------+
| | ------------> | |
| Many | <-----------------------> | One |
| | ------------> | |
+----------+ / +-------------+
/
+----------+ /
| | /
| Many | <-------
| |
+----------+
-- A third port (port 3) on the testing device MUST be connected to For every address, the testing device MUST send learning frames to
a allow the DUT/SUT to update its address tables properly.
port on the DUT/SUT and act as a monitoring port to listen for
flooded frames.
The algorithm for the test is as follows: 5.2.4 Measurements
BEGIN Each receiving port MUST categorize, then count the frames into one
Set Initial Value of N to user specified number, where N is the of two groups:
number of addresses to be verified in each iteration
WHILE NOT Finished DO
PAUSE for the aging time specified
Address learning: Port 1 sends N frames with varying
source addresses to Port 2 to attempt to fill the DUT/SUT
address table for Port #1.
Controlling: Port 2 sends N frames with varying
destination addresses corresponding to Port 1.
IF (Port 3 received a frame during Control phase) OR
(Port 1 did not receive the correct # of frames)
THEN
Address Table of DUT/SUT was full
Set N to lower number (in binary search method)
ELSE
Address Table of DUT/SUT was NOT full
Set N to higher number (in binary search method)
IF High and Low Values of N Meet
THEN
Test is Finished, Value of N equals number of
addresses supported by DUT/SUT
ELSE
Continue Test
END WHILE
DONE
Using a binary search approach, the test targets the exact number
of addresses supported per port with minimal test iterations. Due
to the aging time of DUT/SUT address tables, each iteration may take
some time during the waiting period for the addresses to clear. If
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 address 1.) Received Frames: received frames MUST have the correct
handling has been found. destination MAC address and SHOULD match a signature field.
For this test, the aging time of the DUT/SUT MUST be known. Use a 2.) Flood count: defined in RFC 2285 3.8.3.
short
aging time if possible to reduce the time needed to run the test.
The aging time MUST be longer than the time necessary to produce
packets at the specified rate. If a low frame rate is used for
the test, then it may be possible that sending a large amount of
frames may actually take longer than the aging time. Keep in mind
that the test actually sends twice as many frames as the number
of addresses being tested due to the learning phase and the
controlling phase.
Set the initial value of addresses per port to a number Any frame received which does not have the correct destination
slightly higher than the number of addresses that the DUT/SUT can address MUST not be counted as a received frame and SHOULD be counted
handle. as part of a flood count.
This step primes the binary search and can reduce the number of
iterations required to determine the exact number supported.
Set the forwarding rate to a number that is reasonable to be handled Any frame originating from the DUT/SUT MUST not be counted as a
by the DUT/SUT and one that is high enough so that the test received frame. Frames originating from the DUT/SUT MAY be counted
iterations are as flooded frames or not counted at all.
not too long.
Reporting format: Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
of frames per second that the device is observed to successfully
transmit to the correct destination interface in response to a
specified offered load. The offered load MUST also be cited.
After the test is run, results for each iteration SHOULD be displayed Forwarding rate at maximum offered load (FRMOL) MUST be reported
in a table to include: as the number of frames per second that a device can successfully
transmit to the correct destination interface in response to the
maximum offered load as defined in RFC 2285, section 3.6. The
maximum offered load MUST also be cited.
-- the number of addresses used for each test iteration. Maximum forwarding rate (MFR) MUST be reported as the highest
forwarding rate of a DUT/SUT taken from an iterative set of
forwarding rate measurements. The load applied to the device MUST
also be cited.
-- the frame rate used for each test iteration. 5.2.5 Reporting Format
-- number of control frames that were transmitted by test port The results for these tests SHOULD be reported in the form of a
number 2. Control frames are the frames sent with varying destination graph. The x coordinate SHOULD be the frame size, the y coordinate
addresses to confirm that the DUT/SUT has learned all of the SHOULD be the test results. There SHOULD be at least two lines on
addresses the graph, one plotting the theoretical and one plotting the test
for each test iteration. results.
-- the number of frames received by test port 2 during the control To measure the DUT/SUT's ability to switch traffic while performing
portion of each test. If the number is non-zero, this is an many different address lookups, the number of addresses per port
indication MAY be increased in a series of tests.
of the DUT/SUT flooding a frame in which the destination address is
not
in the address table.
-- the number of frames that test port 1 received during the control 5.3 Head-of-line blocking
portion of the test. This number will include those frames which are
Spanning tree frames. For a normal test iteration, this number SHOULD
be equal to the number of frames transmitted by port 2 during the
control phase.
-- the number of frames that test port 1 received during the control 5.3.1 Objective
phase not including Spanning Tree or other non test generated frames.
In all cases, this number SHOULD be equal to the number of frames
transmitted by port 2 during the control phase of the test.
-- the number of frames test port 3 received during the control To determine how a DUT handles congestion. Namely, does the device
phase implement congestion control and does congestion on one port
of the test. If the value is not zero, then this indicates that for affect an uncongested port?
that test iteration, the DUT/SUT could not determine the proper
destination
port for that many frames. In other words, the DUT/SUT flooded the
frame to
all ports since its address table was full.
5.10 Address Learning Rate 5.3.2 Setup Parameters
Objective: The following parameters MUST be defined. Each variable is
configured with the following considerations.
Once the maximum number of addresses supported per port by the Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
DUT/SUT is 1280 and 1518 bytes, per RFC 2544 section 9. The four CRC bytes
known, the addressing learning rate (the rate at which the DUT/SUT are included in the frame size specified.
learns
these addresses) can be determined.
Procedure: Duplex mode - Half duplex or full duplex.
An algorithm similar to the one used to determine address caching Interframe Gap (IFG) - The IFG between frames MUST be at the
capacity can be used to determine the address learning rate. This minimum specified by the standard (9.6 us for 10Mbps Ethernet,
test iterates the rate at which address learning frames are offered 960 ns for 100Mbps Ethernet, and 96 ns for 1 Gbps Ethernet).
by the test device connected to the DUT/SUT. It is recommended to
set
the number of addresses offered to the DUT/SUT in this test to the
maximum caching capacity. However, the address learning rate might
be
determined for different numbers of addresses but in each test run,
the number MUST remain constant.
Initializing the forwarding rate primes the binary search algorithm Addresses per port - Represents the number of addresses which
and can help to shorten the overall test duration. are being tested for each port. Number of addresses SHOULD be a
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended values are 1, 16 and 256.
A third port on the DUT/SUT MUST listen for flooded frames. Test Duration - Test duration SHOULD be between 1 and 300 seconds.
RFC 2285 recommends a duration of at least 10 seconds for each
test.
In this test, the forwarding rate SHOULD be varied until a rate is 5.3.3 Procedure
found that is the threshold for the rate supported by the DUT/SUT. It
may be useful to pick a value slightly higher than the advertised
forwarding rate.
Reporting format: This test MUST consist of a multiple of four ports. Four ports are
REQUIRED and MAY be expanded to fully utilize the DUT/SUT in
increments of four. Each group of four will contain a test block
with two of the ports as source transmitters and two of the ports as
receivers. The diagram below depicts the flow of traffic between the
switch ports:
To be done. +----------+ 50 % MOL +-------------+
| | ------------------------> | |
| | 50 % MOL | uncongested |
| | --------- | |
+----------+ \ +-------------+
\
\
\
+----------+ \ +-------------+
| | ---------> | |
| | 100 % MOL | congested |
| | ------------------------> | |
+----------+ +-------------+
Section 6. Security Considerations Both source transmitters MUST transmit the exact number of frames.
The first source MUST transmit frames at the MOL with the destination
address of the two receive ports in an alternating order. The first
frame to the uncongested receive port, second frame to the congested
receive port, then repeat. The second source transmitter MUST
transmit frames at the MOL only to the congested receive port.
This document does not yet address Security Considerations. Both receive ports SHOULD distinguish between frames originating from
the source ports and frames originating from the DUT/SUT. Only
frames from the source ports SHOULD be counted.
Section 7. Authors' Address The uncongested receive port should be receiving at a rate of half
the MOL. The number of frames received on the uncongested port
SHOULD be 50% of the frames transmitted by the first source
transmitter. The congested receive port should be receiving at the
MOL. The number of frames received on the congested port should be
between 100% and 150% of the frames transmitted by one source
transmitter.
Robert Mandeville Frames destined to uncongested ports in a switch device should not
European Network Laboratories (ENL) be dropped due to other ports being congested, even if the source
2, rue Helene Boucher is sending to both the congested and uncongested ports.
87286 Guyancourt Cedex
France
Phone: + 33 1 39 44 12 05 5.3.4 Measurements
EMail: bob@enl.net
Judy Keene Any frame received which does not have the correct destination
Netcom Systems address MUST not be counted as a received frame and SHOULD be counted
20550 Nordhoff St. as part of a flood count.
Chatsworth, CA 91311
USA
Phone: +1 818 700 5100 Any frame originating from the DUT/SUT MUST not be counted as a
Email: judy_keene@netcomsystems.com received frame. Frames originating from the DUT/SUT MAY be counted
as flooded frames or not counted at all.
Appendix A: Calculating the Interburst Gap Frame loss rate of the DUT/SUT's congested and uncongested ports MUST
be reported as defined in RFC 2544 section 26.3 with the following
notes: Frame loss rate SHOULD be measured at the end of the test
duration. The term "rate", for this measurement only, does not imply
the units in the fashion of "per seconds."
IBG is defined in RFC 2285 as a function of maximum media rate (also Forwarding rate (FR) of the DUT/SUT's congested and uncongested ports
known as line rate), the length of the frames in the bursts with the MUST be reported as the number of frames per second that the device
preamble and the interframe gap (IFG), the number of frames in the is observed to successfully transmit to the correct destination
bursts, interface in response to a specified offered load. The offered load
and the intended load. MUST also be cited.
Using the burst size, frame size and the load per port, the IBG can 5.3.5 Reporting format
be
calculated:
Burst size * ((preamble 64 + (frame size * 8 bits) + 96 IFG bit This test MUST report the frame lost rate at the uncongested port,
times)) the maximum forwarding rate (at 50% offered load) at the uncongested
* 1 (for full duplex) or .5 (for half duplex) port, and the frame lost rate at the congested port. This test MAY
(10 bit times equal 1 microsecond) report the frame counts transmitted and frame counts received by the
ports.
Example: If the DUT implements a flow control mechanism, an indication of this
is presented by observing no frame loss on the congested port. It
should be noted that this test expects the overall load to the
congested port to be greater than 100%. Therefore if the load is
greater than 100% and no frame loss is detected, then the DUT must be
implementing a flow control mechanism. The type of flow control
mechanism used is beyond the scope of this memo.
Burst size = 24 If there is frame loss at the uncongested port, "Head of Line"
Frame size = 64 blocking exists. The DUT cannot forward the amount of traffic to the
congested port and as a result it is also losing frames destined to
the uncongested port.
24 * (64 + 64*8 + 96) = 24 * (672) = 16,128 bit/times = It should be noted that some DUTs may not be able to handle the 100%
1612.8 us IBG load presented at the input port. In this case, there may be frame
loss reported at the uncongested port which is due to the load at the
input port rather than the congested port's load.
In half duplex mode, exactly half of the target load SHOULD be sent If the uncongested frame loss is reported as zero, but the maximum
to each of the ports under test. For example, with a 100% load of forwarding rate is less than 7440 (for 10Mbps Ethernet), then this
64-byte frames, the target load for each port under test is 7440 may be an indication of congestion control being enforced by the DUT.
frames received per second and 7440 frames transmitted per second In this case, the congestion control is affecting the throughput of
(for 10Mbps Ethernet). the uncongested port.
Recommended characteristic values for burst size are: If no congestion control is detected, the expected percentage frame
loss for the congested port is 33% at 150% overload. It is receiving
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%).
2 15 60 240 930 5.4 Partially Meshed Multiple Devices
3 16 62 248
4 20 80 310
5 24 93 372
6 30 120 465
8 31 124 496
10 40 155 620
12 48 186 744
Network Working Group R. Mandeville 5.4.1 Objective
Internet-Draft European Network Laboratories
Expiration Date: February 1999 J. Keene
Netcom Systems
August 1998
Benchmarking Methodology for LAN Switching Devices To determine the throughput, frame loss and forwarding rates of two
<draft-ietf-bmwg-mswitch-00.txt> switching devices equipped with multiple Ethernet ports and one high
speed backbone uplink (Gigabit Ethernet, ATM, SONET).
Status of this Memo 5.4.2 Setup Parameters
This document is an Internet-Draft. Internet-Drafts are working When offering bursty partially meshed traffic, the following
documents of the Internet Engineering Task Force (IETF),its areas, parameters MUST be defined. Each variable is configured with the
and its working groups. Note that other groups may also distribute following considerations.
working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
and may be updated, replaced, or obsoleted by other documents at any 1280 and 1518 bytes, per RFC 2544 section 9. The four CRC bytes
time. It is inappropriate to use Internet-Drafts as reference are included in the frame size specified.
material or to cite them other than as "work in progress."
To view the entire list of current Internet-Drafts, please check Interframe Gap (IFG) - The IFG between frames inside a burst
the "1id-abstracts.txt" listing contained in the Internet-Drafts MUST be at the minimum specified by the standard (9.6 us for
Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net 10Mbps Ethernet, 960 ns for 100Mbps Ethernet, and 96 ns for
(Northern Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au 1 Gbps Ethernet).
(Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu
(US West Coast).
This memo provides information for the Internet community. This memo Interburst Gap (IBG) - This is the interval between bursts of
does not specify an Internet standard of any kind. Distribution of traffic. Refer to Appendix A, Calculating Interburst Gap, for
this memo is unlimited. the formula used to compute IBG.
Abstract Duplex mode - Half duplex or full duplex.
This document is intended to provide methodology for the benchmarking Load / Port - Load per port is expressed in a percentage of the
of local area network (LAN) switching devices. It extends the medium's maximum intended load possible. The actual transmitted
methodology already defined for benchmarking network interconnecting frame per second is dependent upon half duplex or full duplex
devices in RFC 1944 to switching devices. operation. The test SHOULD be run multiple times with a different
load per port in each case.
This RFC primarily deals with devices which switch frames at the In half duplex mode, exactly half of the intended load SHOULD be
Medium Access Control (MAC) layer. Itprovides a methodology for transmitted to each of the ports under test. For example, with a
benchmarking switching devices, forwarding performance, congestion 100% load of 64-byte frames, the intended load for each port under
control, latency, address handling and filtering. In addition to test is 7440 frames received per second and 7440 frames
defining the tests, this document also describes specific formats for transmitted per second (for 10Mbps Ethernet).
reporting the results of the tests.
1. Introduction In full duplex mode, the entire intended load SHOULD be
This document defines a specific set of tests to measure and report transmitted to each of the ports under test. For example, with a
the performance characteristics of network switching devices. 100% load of 64-byte frames, the intended load for each port under
test is 14880 frames received per second and 14880 frames
transmitted per second (for 10Mbps Ethernet).
A previous document, "Benchmarking Terminology for LAN Switching Burst Size - The burst size defines the number of frames sent
Devices" (RFC 2285), defined many of the terms that are used in this back-to-back at the minimum legal IFG (96 bit times) before
document. The terminology document SHOULD be consulted before pausing transmission to receive frames. Burst sizes
attempting to make use of this document. SHOULD vary between 1 and 930 frames.
2. Requirements Addresses per port - Represents the number of addresses which
are being tested for each port. Number of addresses SHOULD be a
binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
Recommended values are 1, 16 and 256.
The following RFCs SHOULD be consulted before attempting to make use Test Duration - Test duration SHOULD be between 1 and 300 seconds.
of this document: RFC 2285 recommends a duration of at least 10 seconds for each
test.
* RFC 1242 "Benchmarking Terminology for Network Interconnect Local Traffic - A Boolean value of ON or OFF. The frame
Devices" sequence
algorithm MAY be altered to remove local traffic. With local
traffic ON, the algorithm is exactly the same as a fully meshed
throughput. With local traffic OFF, the port sends frames to all
other ports on the other side of the backbone uplink in a round
robin type fashion.
* RFC 1944 "Benchmarking Methodology for Network Interconnect 5.4.3 Procedure
Devices"
* RFC 2285 "Benchmarking Terminology for LAN Switching Devices" All ports MUST transmit the exact number of frames. All ports SHOULD
start transmitting their frames within 1% of the test duration. For
a test duration of 10 seconds, all ports SHOULD have started
transmitting frames with 100 milliseconds of each other.
For the sake of clarity and continuity, this RFC adopts the template Each port in the test MUST send frames to all other ports in a
for benchmarking tests set out in Section 26 of RFC 1944. round robin type fashion as defined in section 5.1. Local traffic
MAY be removed from the round robin list in order to send the entire
load across the backbone uplink.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", For tests using multiple addresses per port, the actual port
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in destinations are the same as described above and the actual
this document are to be interpreted as described in RFC 2119. source/destination address pairs SHOULD be chosen randomly to
exercise the DUT/SUT's ability to perform address lookups.
3. Test setup For every address, the testing device MUST send learning frames to
allow the DUT/SUT to update its address tables properly.
This document extends the general test setup described in section 6 To measure the DUT/SUT's ability to switch traffic while performing
of RFC 1944 to the benchmarking of LAN switching devices. RFC 1944 many different address lookups, the number of addresses per port
primarily describes non-meshed traffic where input and output MAY be increased in a series of tests.
interfaces are grouped in mutually exclusive sending and
receiving pairs. In fully meshed traffic, each interface of a
DUT/SUT is set up to both receive and transmit frames to all
the other interfaces under test.
Prior to each test run, the DUT/SUT MUST learn the MAC addresses used 5.4.4 Measurements
in
the test and the address learning MUST be verified to avoid flooded
frames being counted as correctly received frames. The forwarding
rate, namely the rate at which address learning frames are offered
may
have to be adjusted to be as low as 50 frames per second or even
less,
to guarantee successful learning. The DUT/SUT address aging time
SHOULD be
configured to be greater than the period between the learning phase
of
the test and the test run; in non-meshed and partially meshed tests,
the aging time SHOULD at a minimum be set to at least the length of
the test period. More than one trial may be needed for the
association
of the address to the port to occur.
If a DUT/SUT uses a hashing algorithm with address learning, the Each port should receive the same amount of frames that is
DUT/SUT may not learn the necessary addresses to perform the tests. transmitted. Each receiving port MUST categorize, then count the
The format of the MAC addresses MUST be adjustable so that the frames into one of two groups:
address
mapping may be re-arranged to make a DUT/SUT learn addresses
without confusion.
It is recommended that SNMP and Spanning Tree be disabled when bench- 1.) Received frames MUST have the correct destination MAC address
marking switching devices unless investigating overhead behavior. If and SHOULD match a signature field.
such protocols cannot be turned off, it is recommended that the
levels of offered load be reduced (less than 100%) to allow for
the additional management frames.
4. Frame formats and sizes 2.) Flood count (defined in RFC 2285 3.8.3).
For frame formats and sizes, refer to RFC 1944, sections 8 and 9 and Any frame received which does not have the correct destination
Appendix C. address MUST not be counted as a received frame and SHOULD be counted
as part of a flood count.
There are three frame formats for layer 2 Ethernet switches: Any frame originating from the DUT/SUT MUST not be counted as a
standard MAC Ethernet frames, standard MAC Ethernet frames received frame. Frames originating from the DUT/SUT MAY be counted
with vendor-specific tags added to them, and IEEE 802.3ab as flooded frames or not counted at all.
frames tagged to accommodate 802.3p,q. The two types of tagged
frames may exceed the standard maximum length frame of 1518 bytes,
and
may not be accepted by the interface controllers of some DUT/SUTs.
It is recommended to check the compatibility of the DUT/SUT
with tagged frames before testing.
Devices switching tagged frames of over 1518 bytes will have a lower Frame loss rate of the DUT/SUT SHOULD be reported as defined in
maximum forwarding rate than standard untagged frames. RFC 2544 section 26.3 with the following notes: Frame loss rate
SHOULD be measured at the end of the test duration. The term "rate",
for this measurement only, does not imply the units in the fashion of
"per seconds."
5. Benchmarking Tests Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
of frames per second that the device is observed to successfully
transmit to the correct destination interface in response to a
specified offered load. The offered load MUST also be cited.
The following tests offer objectives, procedures, and reporting Forwarding rate at maximum offered load (FRMOL) MUST be reported
formats for benchmarking LAN switching devices. as the number of frames per second that a device can successfully
transmit to the correct destination interface in response to the
maximum offered load as defined in RFC 2285, section 3.6. The
maximum offered load MUST also be cited.
5.1 Fully meshed throughput, frame loss and forwarding rates Maximum forwarding rate (MFR) MUST be reported as the highest
5.2 Partially meshed overloading forwarding rate of a DUT/SUT taken from an iterative set of
5.3 Head of line blocking forwarding rate measurements. The load applied to the device MUST
5.4 Partially meshed multiple devices also be cited.
5.5 Multiple streams of unidirectional traffic
5.6 Filter illegal frames
5.7 Broadcast frame handling and latency
5.8 Maximum forwarding rate and minimum interframe gap
5.9 Address caching capacity
5.10 Address learning rate
5.1 Fully meshed throughput, frame loss and forwarding rates 5.4.5 Reporting format
Objective: The results for these tests SHOULD be reported in the form of a
graph. The x coordinate SHOULD be the frame size, the y coordinate
SHOULD be the test results. There SHOULD be at least two lines on
the graph, one plotting the theoretical and one plotting the test
results.
To determine the throughput, frame loss and forwarding rates of To measure the DUT/SUT's ability to switch traffic while performing
DUT/SUTs many different address lookups, the number of addresses per port
offered fully meshed traffic as defined in RFC 2285. MAY be increased in a series of tests.
Procedure: 5.5 Multiple streams of unidirectional traffic
RFC 2285 points out that when offering bursty meshed traffic, the 5.5.1 Objective
variables which MUST be defined are frame size, bust size,
interframe gap, interburst gap, and load. Each variable is To determine the throughput of the DUT/SUT when presented multiple
streams of unidirectional traffic with half of the ports on the
DUT/SUT are receiving frames destined to the other half of the
ports.
5.1.2 Setup Parameters
The following parameters MUST be defined. Each variable is
configured with the following considerations. configured with the following considerations.
Interframe Gap (IFG) - The IFG between frames inside a burst Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024,
MUST 1280 and 1518 bytes, per RFC 2544 section 9. The four CRC bytes
be at the minimum specified by the standard (9.6 us for 10Mbps are included in the frame size specified.
Ethernet and 0.96 us for 100Mbps Ethernet).
Interburst Gap (IBG) - This is the interval between bursts of Duplex mode - Half duplex or full duplex.
traffic. Refer to Appendix A, Calculating Interburst Gap, for
the formula used to compute IBG.
Load / Port - The test SHOULD be run multiple times with a Load / Port - Load per port is expressed in a percentage of the
different load per port in each case. The 100% load translates to medium's maximum intended load possible. The actual transmitted
a transmit load of 50% for half duplex. This type of test SHOULD frame per second is dependent upon half duplex or full duplex
also be run at higher than 100% loads. operation. The test SHOULD be run multiple times with a different
load per port in each case.
In half duplex mode, exactly half of the target load SHOULD be In half duplex mode, exactly half of the intended load SHOULD be
sent to each of the ports under test. For example, with a 100% transmitted to each of the ports under test. For example, with a
load of 64-byte frames, the target load for each port under test 100% load of 64-byte frames, the intended load for each port under
is 7440 frames received per second and 7440 frames transmitted per test is 7440 frames received per second and 7440 frames
second (for 10Mbps Ethernet). transmitted per second (for 10Mbps Ethernet).
Frame Size - Recommended frame sizes are 64, 128, 256, 512, 1024, In full duplex mode, the entire intended load SHOULD be
1280 and 1518 bytes, per RFC 1944 section 9. transmitted to each of the ports under test. For example, with a
100% load of 64-byte frames, the intended load for each port under
test is 14880 frames received per second and 14880 frames
transmitted per second (for 10Mbps Ethernet).
Burst Size - The burst size defines the number of packets sent Addresses per port - Represents the number of addresses which
back-to-back at the minimum legal IFG (96 bit times) before are being tested for each port. Number of addresses SHOULD be a
pausing transmission to receive frames. Burst sizes binary exponential (i.e. 1, 2, 4, 8, 16, 32, 64, 128, 256, ...).
SHOULD vary between 1 and 930 frames. Recommended values are 1, 16 and 256.
To avoid truncating bursts, a burst size SHOULD be an even Test Duration - Test duration SHOULD be between 1 and 300 seconds.
multiple into 7440. 7440 is the maximum frames per second for half RFC 2285 recommends a duration of at least 10 seconds for each
duplex mode; 14880 is the maximum frames per second for full test.
duplex mode. Refer to Appendix A for a table of recommended burst
values.
Each port in the test sends frames to all other ports in a round- 5.5.3 Procedure
robin type fashion. The following table shows how each port in a test
SHOULD transmit frames to all other ports in the test. In this Ports do not send and receive frames simultaneously. As a
example, there are six ports with 1 address per port: consequence, there should be no collisions unless the DUT is
misforwarding frames, generating flooded or Spanning-Tree frames or
is enabling some flow control mechanism. Ports used for this test
are either transmitting or receiving, but not both. Those ports which
are transmitting send frames destined to addresses corresponding to
each of the ports receiving. This creates a unidirectional mesh of
traffic.
All ports MUST transmit the exact number of frames. All ports SHOULD
start transmitting their frames within 1% of the test duration. For
a test duration of 10 seconds, all ports SHOULD have started
transmitting frames with 100 milliseconds of each other.
Each transmitting port in the test MUST send frames to all receiving
ports in a round robin type fashion. The following table shows how
each port in a test MUST transmit frames to all other ports in the
test. In this 8 port 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) Source Port, then Destination Ports (in order of transmission)
Port #1 2 3 4 5 6 2... Port #1 5 6 7 8 5 6...
Port #2 3 4 5 6 1 3... Port #2 6 7 8 5 6 7...
Port #3 4 5 6 1 2 4... Port #3 7 8 5 6 7 8...
Port #4 5 6 1 2 3 5... Port #4 8 5 6 7 8 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 destination As shown in the table, there is an equal distribution of destination
addresses for each transmit opportunity. This keeps the test balanced addresses for each transmit opportunity. This keeps the test balanced
so that one destination port is not overloaded by the test algorithm so that one destination port is not overloaded by the test algorithm
and all ports are equally and fully loaded throughout the test. For and all receiving ports are equally and fully loaded throughout the
tests using multiple addresses per port, the actual port destinations test. Not following this algorithm exactly will product inconsistent
are the same as described above and the actual source/destination results.
address
pairs are chosen randomly to exercise the DUT/SUT's ability to
perform
address lookups.
For every address, the testing device sends learning packets to allow For tests using multiple addresses per port, the actual port
the DUT/SUT to load its address tables properly. destinations are the same as described above and the actual
source/destination address pairs SHOULD be chosen randomly to
exercise the DUT/SUT's ability to perform address lookups.
For every address, the testing device MUST send learning frames to
allow the DUT/SUT to load its address tables properly. The address
table's aging time SHOULD be set sufficiently longer than the
learning time and test duration time combined. If the address table
ages out during the test, the results will show a lower performing
DUT/SUT.
To measure the DUT/SUT's ability to switch traffic while performing To measure the DUT/SUT's ability to switch traffic while performing
many many different address lookups, the number of addresses per port
different address lookups, the number of addresses per port SHOULD be MAY be increased in a series of tests.
increased in a series of tests.
Reporting format: 5.5.4 Measurements
In these tests, a port SHOULD transmit and receive the same amount of Each port should receive the same number of frames that it
packets. Each port MUST count the packets received with a valid transmitted. Each receiving port MUST categorize, then count the
address. frames into one of two groups:
Any packet received which does not have a valid address MUST not be
counted as a received packet and can be counted as part of a flood
count as described in 3.8.3 in RFC 2285.
The results for these tests SHOULD be reported in the form of 1.) Received Frames: received frames MUST have the correct
numerical destination MAC address and SHOULD match a signature field.
data or a graph with text to indicate the data type. The data types
for 2.) Flood count: defined in RFC 2285 3.8.3.
the throughput test and for the frame loss rate test are described in
RFC 1944. Any frame received which does not have the correct destination
address MUST not be counted as a received frame and SHOULD be counted
as part of a flood count.
Any frame originating from the DUT/SUT MUST not be counted as a
received frame. Frames originating from the DUT/SUT MAY be counted
as flooded frames or not counted at all.
Frame loss rate of the DUT/SUT SHOULD be reported as defined in
RFC 2544 section 26.3 with the following notes: Frame loss rate
SHOULD be measured at the end of the test duration. The term "rate",
for this measurement only, does not imply the units in the fashion of
"per seconds."
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
of of frames per second that the device is observed to successfully
frames per second that the device is observed to successfully transmit to the correct destination interface in response to a
transmit specified offered load. The offered load MUST also be cited.
to the correct destination interface in response to a specified
offered
load. The offered load MUST also be cited.
Forwarding rate at maximum offered load (FRMOL ) SHOULD be reported Forwarding rate at maximum offered load (FRMOL) MUST be reported
as as the number of frames per second that a device can successfully
the number of frames per second that a device can successfully transmit to the correct destination interface in response to the
transmit maximum offered load as defined in RFC 2285, section 3.6. The
to the correct destination interface in response to the maximum maximum offered load MUST also be cited.
offered
load as defined in RFC 2285, section 3.6. The maximum offered load Maximum forwarding rate (MFR) MUST be reported as the highest
MUST forwarding rate of a DUT/SUT taken from an iterative set of
forwarding rate measurements. The load applied to the device MUST
also be cited. also be cited.
Maximum forwarding rate (MFR) SHOULD be reported as the highest 5.1.5 Reporting format
forwarding
rate of a DUT/SUT taken from an iterative set of forwarding rate
measurements. The load applied to the device MUST also be cited.
5. 2 Partially meshed overloading The results for these tests SHOULD be reported in the form of a
graph. The x coordinate SHOULD be the frame size, the y coordinate
SHOULD be the test results. There SHOULD be at least two lines on
the graph, one plotting the theoretical and one plotting the test
results.
To be done. To measure the DUT/SUT's ability to switch traffic while performing
many different address lookups, the number of addresses per port
MAY be increased in a series of tests.
5. 3 Head-of-line blocking 5.6 Filter illegal frames
To be done. 5.6.1 Objective
5.4 Partially Meshed Multiple Devices The objective of the filter illegal frame test is to determine
the behavior of the DUT under errors 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.
To be done. 5.1.2 Setup Parameters
5.5 Multiple streams of unidirectional traffic The following parameters MUST be defined. Each variable is
configured with the following considerations.
To be done. Load / Port - Load per port is expressed in a percentage of the
medium's maximum intended load possible. The actual transmitted
frame per second is dependent upon half duplex or full duplex
operation. The test SHOULD be run multiple times with a different
load per port in each case.
5.6 Filter illegal frames Test Duration - Test duration SHOULD be between 1 and 300 seconds.
RFC 2285 recommends a duration of at least 10 seconds for each
test.
To be done. 5.6.3 Procedure
Each of the illegal frames for Ethernet MUST be checked:
Oversize - The DUT/SUT MAY filter frames larger than 1518 bytes
from being propagated through the DUT/SUT (ISO 8802-3 4.2.4.2.1).
Oversized frames transmitted to the DUT/SUT should not appear as
receive frames or as error frames on any port. DUT/SUT supporting
tagged Frames MAY forward frames up to and including 1522 bytes
long (IEEE 802.3ac 4.2.4.2.1).
Undersize - The DUT/SUT MUST filter frames less than 64 bytes from
being propagated through the DUT/SUT (per ISO 8802-3 4.2.4.2.2).
Undersized frames (or collision fragments) transmitted to the DUT/SUT
MUST not appear as receive frames or as error frames on another port.
CRC Errors - The DUT/SUT MUST filter frames that fail the Frame Check
Sequence Validation (ISO 8802-3 4.2.4.1.2) from being propagated
through the DUT/SUT. Frames with an invalid CRC transmitted to the
DUT/SUT should not appear as receive frames or as error frames on
another port.
Dribble Bit Errors - The DUT/SUT MUST correct and forward frames
containing dribbling bits. Frames transmitted to the DUT/SUT that do
not end in an octet boundary but contain a valid frame check sequence
MUST be accepted by the DUT/SUT (ISO 8802-3 4.2.4.2.1) and forwarded
to the correct receive port with the frame ending in an octet
boundary (ISO 8802-3 3.4).
Alignment Errors - The DUT/SUT MUST filter frames than fail the Frame
Check Sequence Validation AND do not end in an octet boundary. This
is a combination of a CRC error and a Dribble Bit error. When both
errors are occurring in the same frame, the DUT/SUT MUST determine
the CRC error takes precedence and filters the frame (ISO 8802-3
4.2.4.1.2) from being propagated.
5.7 Broadcast frame handling and latency test 5.7 Broadcast frame handling and latency test
To be done. 5.7.1 Objective
The objective of the Broadcast Frame Handling and Latency Test is to
determine the throughput and latency of the DUT when handling
broadcast traffic. The ability to forward broadcast frames will
depend on special features built into the device for that purpose.
It is therefore necessary to determine the ability of switches to
handle broadcast frames, since there may be many different ways of
implementing such a feature.
5.7.2 Setup Parameters
The following parameters MUST be defined. Each variable is
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. The four CRC bytes
are included in the frame size specified.
Duplex mode - Half duplex or full duplex.
Load / Port - Load per port is expressed in a percentage of the
medium's maximum intended load possible. The actual transmitted
frame per second is dependent upon half duplex or full duplex
operation. The test SHOULD be run multiple times with a different
load per port in each case.
In half duplex mode, exactly half of the intended load SHOULD be
transmitted to each of the ports under test. For example, with a
100% load of 64-byte frames, the intended load for each port under
test is 7440 frames received per second and 7440 frames
transmitted per second (for 10Mbps Ethernet).
In full duplex mode, the entire intended load SHOULD be
transmitted to each of the ports under test. For example, with a
100% load of 64-byte frames, the intended load for each port under
test is 14880 frames received per second and 14880 frames
transmitted per second (for 10Mbps Ethernet).
Test Duration - Test duration SHOULD be between 1 and 300 seconds.
RFC 2285 recommends a duration of at least 10 seconds for each
test.
5.7.3 Procedure
For this test, there are two parts to be run.
Broadcast Frame Throughput - This portion of the test uses a single
source test port to transmit frames with a broadcast address using
the frame specified in RFC 2544. Selected receive ports then
measure the forwarding rate and Frame loss rate.
Broadcast Frame Latency - This test uses the same setup as the
Broadcast Frame throughput, but instead of a large stream of frames
being sent, only one frame is sent and the latency to each of the
receive ports are measured in seconds.
5.7.4 Measurements
Frame loss rate of the DUT/SUT SHOULD be reported as defined in
RFC 2544 section 26.3 with the following notes: Frame loss rate
SHOULD be measured at the end of the test duration. The term "rate",
for this measurement only, does not imply the units in the fashion of
"per seconds."
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
of frames per second that the device is observed to successfully
transmit to the correct destination interface in response to a
specified offered load. The offered load MUST also be cited.
5.8 Maximum forwarding rate and minimum interframe gap 5.8 Maximum forwarding rate and minimum interframe gap
To be done. 5.8.1 Objective
The objective of the Maximum forwarding rate test is to find the
peak value of the Forwarding Rate when the Offered Load is varied
between the throughput (RFC 1242) and the Maximum Offered Load
(RFC 2285).
The Minimum Interframe gap Test overloads a DUT/SUT port and measure
the output for forward pressure. If the DUT/SUT transmits frames
with an interframe gap less than 96 bits (ISO 8802-3 4.2.3.2.2), then
forward pressure is detected.
5.8.2 Setup Parameters
The following parameters MUST be defined. Each variable is
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. The four CRC bytes
are included in the frame size specified.
Duplex mode - Half duplex or full duplex.
Test Duration - Test duration SHOULD be between 1 and 300 seconds.
RFC 2285 recommends a duration of at least 10 seconds for each
test.
Step Size - The minimum incremental resolution that the Offered
Load (OL) will be incremented in frames per second. The smaller
the step size, the more accurate the measurement and the more
iterations required. As the Offered Load approaches the Maximum
Offered Load, the minimum step size will increase because of gap
resolution on the testing device.
5.8.3 Procedure
If the throughput and the Maximum Offered Load are the same, then
Maximum Forwarding rate is equal to the Maximum Offered Load.
This test SHOULD at a minimum be performed in a two-port
configuration as described below. Learning frames MUST be sent to
allow the DUT/SUT to update its address tables properly.
The first port (port 1) device transmits frames at the Offered Load
to the DUT/SUT. A second port (port 2) receives frames from the
DUT/SUT and measures the Forwarding Rate.
The Offered Load is incremented for each Step Size to find the
Maximum Forwarding Rate. The algorithm for the test is as follows:
CONSTANT
MOL = ... frames/sec; {Maximum Offered Load}
VARIABLE
MFR := 0 frames/sec; {Maximum Forwarding Rate}
OLOAD := starting throughput in frames/sec; {offered load}
STEP := ... frames/sec; {Step Size}
BEGIN
OLOAD := OLOAD - STEP;
DO
BEGIN
OLOAD := OLOAD + STEP
IF (OLOAD > MOL) THEN
BEGIN
OLOAD := MOL
END
AddressLearning; {Port 2 broadcast frame with its source
address}
Transmit(OLOAD); {Port 1 sends frames to Port 2 at Offered load}
IF (Port 2 Forwarding Rate > MFR) THEN
BEGIN
MFR := Port 2 Forwarding Rate; {A higher value than before}
END
END
WHILE (OLOAD >= MOL); {MFR equals Maximum Forwarding Rate}
DONE
The Minimum Interframe gap test SHOULD, at a minimum, be performed in
a two-port configuration as described below. Learning frames MUST be
sent to allow the DUT/SUT to update its address tables properly.
The first port (port 1) device transmits frames with an interframe
gap of 88 bits to the DUT/SUT. This will apply forward pressure to
the DUT/SUT and overload it at a rate of one byte per frame. The
frames MUST be constructed with a source address of port 1 and a
destination address of port 2.
A second port (port 2) receives frames from the DUT/SUT and measures
the Forwarding Rate. The measured Forwarding Rate SHOULD not exceed
the medium's maximum theoretical utilization.
5.8.4 Measurements
Port 2 MUST categorize, then count the frames into one of two groups:
1.) Received Frames: received frames MUST have the correct
destination MAC address and SHOULD match a signature field.
2.) Flood count: defined in RFC 2285 3.8.3.
Any frame received which does not have the correct destination
address MUST not be counted as a received frame and SHOULD be counted
as part of a flood count.
Any frame originating from the DUT/SUT MUST not be counted as a
received frame. Frames originating from the DUT/SUT MAY be counted
as flooded frames or not counted at all.
5.8.5 Reporting format
Maximum forwarding rate (MFR) MUST be reported as the highest
forwarding rate of a DUT/SUT taken from an iterative set of
forwarding rate measurements. The load applied to the device MUST
also be cited.
Forwarding rate (FR) of the DUT/SUT SHOULD be reported as the number
of frames per second that the device is observed to successfully
transmit to the correct destination interface in response to a
specified offered load. The offered load MUST also be cited.
5.9 Address Caching Capacity 5.9 Address Caching Capacity
Objective: 5.9.1 Objective
To determine the address caching capacity of a LAN switching device To determine the address caching capacity of a LAN switching device
as defined in RFC 2285, section 3.8.1. as defined in RFC 2285, section 3.8.1.
Procedure: 5.9.2 Setup Parameters
The following parameters MUST be defined. Each variable is
configured with the following considerations.
Age Time - The maximum time that a DUT/SUT will keep a learned
address in its forwarding table.
Addresses Learning Rate - The rate at which new addresses are
offered to the DUT/SUT to be learned. The rate at which address
learning frames are offered may have to be adjusted to be as low as
50 frames per second or even less, to guarantee successful
learning.
Initial Addresses - The initial number of addresses to start the
test with. The number MUST be between 1 and the maximum number
supported by the implementation.
5.9.3 Procedure
The aging time of the DUT/SUT MUST be known. The aging time MUST be
longer than the time necessary to produce frames at the specified
rate. If a low frame rate is used for the test, then it may be
possible that sending a large amount of frames may actually take
longer than the aging time.
This test SHOULD at a minimum be performed in a three-port This test SHOULD at a minimum be performed in a three-port
configuration as described below. configuration as described below.
The first port (port 1) of the testing device is connected to the This test MUST consist of a multiple of three ports. Three ports
DUT/SUT are REQUIRED and MAY be expanded to fully utilized the DUT/SUT in
and is the port from which a testing device sends frames with varying increments of three. Each group of three will contain a test
source addresses and a fixed destination address corresponding to the block as follows:
MAC
address of the receiving port. By receiving frames with varying
source
addresses, the DUT/SUT will learn these new addresses from the
sending port
of the test device.
A second port (port 2) of the testing device is connected to the The first port (port 1) send frames with varying source addresses and
DUT/SUT a fixed destination address corresponding to the MAC address of the
and acts as the receiving port for the address learning frames. This receiving port (port 2) of the DUT/SUT. By receiving frames with
port also sends "control" frames back to the addresses learned varying source addresses, the DUT/SUT will learn these new addresses
on the first port. The algorithm for this is explained below. from the sending port of the test device. The source addresses MAY
be in sequential order.
-- A third port (port 3) on the testing device MUST be connected to A second port (port 2) acts as the receiving port for the address
a learning frames. This port also sends test frames back to the
port on the DUT/SUT and act as a monitoring port to listen for addresses learned on the first port. The algorithm for this is
flooded frames. explained below.
A third port (port 3) on the DUT/SUT act as a monitoring port to
listen for flooded frames.
It is highly recommended that SNMP, Spanning Tree, and any other
frames originating from the DUT/SUT be disabled when running this
test. If such protocols cannot be turned off, the flood count MUST
be modified only to count frame originating from port 1 and MUST
NOT count frames originating from the DUT/SUT.
The algorithm for the test is as follows: The algorithm for the test is as follows:
CONSTANT
AGE = ...; {value greater that DUT aging time}
MAX = ...; {maximum address support by implementation}
VARIABLE
LOW := 0; {Highest passed valve}
HIGH := MAX; {Lowest failed value}
N := ...; {user specified initial starting point}
BEGIN BEGIN
Set Initial Value of N to user specified number, where N is the DO
number of addresses to be verified in each iteration BEGIN
WHILE NOT Finished DO PAUSE(AGE); {Age out any learned addresses}
PAUSE for the aging time specified AddressLearning(Port 2); {broadcast a frame with its source
Address learning: Port 1 sends N frames with varying Address and broadcast destination}
source addresses to Port 2 to attempt to fill the DUT/SUT AddressLearning(Port 1); {N frames with varying source
address table for Port #1. addresses
Controlling: Port 2 sends N frames with varying to Port 2}
destination addresses corresponding to Port 1. Transmit(Port 2); {N frames with varying destination addresses
IF (Port 3 received a frame during Control phase) OR corresponding to Port 1}
(Port 1 did not receive the correct # of frames) IF (Port 3 receive frame != 0) OR
THEN (Port 1 receive frames < Port 2 transmit) THEN
Address Table of DUT/SUT was full BEGIN {Address Table of DUT/SUT was full}
Set N to lower number (in binary search method) HIGH := N;
ELSE END
Address Table of DUT/SUT was NOT full
Set N to higher number (in binary search method)
IF High and Low Values of N Meet
THEN
Test is Finished, Value of N equals number of
addresses supported by DUT/SUT
ELSE ELSE
Continue Test BEGIN {Address Table of DUT/SUT was NOT full}
END WHILE LOW := N;
DONE END
Using a binary search approach, the test targets the exact number N := LOW + (HIGH - LOW)/2;
of addresses supported per port with minimal test iterations. Due END WHILE (HIGH - LOW < 2);
END {Value of N equals number of addresses supported by DUT/SUT}
Using a binary search approach, the test targets the exact number of
addresses supported per port with consistent test iterations. Due
to the aging time of DUT/SUT address tables, each iteration may take to the aging time of DUT/SUT address tables, each iteration may take
some time during the waiting period for the addresses to clear. If some time during the waiting period for the addresses to clear. If
possible, configure the DUT/SUT for a low value for the aging time. 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 address Once the high and low values of N meet, then the threshold of address
handling has been found. handling has been found.
For this test, the aging time of the DUT/SUT MUST be known. Use a 5.9.4 Measurements
short
aging time if possible to reduce the time needed to run the test.
The aging time MUST be longer than the time necessary to produce
packets at the specified rate. If a low frame rate is used for
the test, then it may be possible that sending a large amount of
frames may actually take longer than the aging time. Keep in mind
that the test actually sends twice as many frames as the number
of addresses being tested due to the learning phase and the
controlling phase.
Set the initial value of addresses per port to a number
slightly higher than the number of addresses that the DUT/SUT can
handle.
This step primes the binary search and can reduce the number of
iterations required to determine the exact number supported.
Set the forwarding rate to a number that is reasonable to be handled Whether the offered addresses per port was successful forwarded
by the DUT/SUT and one that is high enough so that the test without flooding.
iterations are
not too long.
Reporting format: 5.9.5 Reporting format
After the test is run, results for each iteration SHOULD be displayed After the test is run, results for each iteration SHOULD be displayed
in a table to include: in a table to include:
-- the number of addresses used for each test iteration. The number of addresses used for each test iteration (varied).
-- the frame rate used for each test iteration. The intended load used for each test iteration (fixed).
-- number of control frames that were transmitted by test port Number of test frames that were transmitted by test port number 2.
number 2. Control frames are the frames sent with varying destination This SHOULD match the number of addresses used for the test
addresses to confirm that the DUT/SUT has learned all of the iteration. Test frames are the frames sent with varying
addresses destination addresses to confirm that the DUT/SUT has learned
for each test iteration. all of the addresses for each test iteration.
-- the number of frames received by test port 2 during the control The flood count on port 2 during the test portion of each test.
portion of each test. If the number is non-zero, this is an If the number is non-zero, this is an indication of the DUT/SUT
indication flooding a frame in which the destination address is not in the
of the DUT/SUT flooding a frame in which the destination address is address table.
not
in the address table.
-- the number of frames that test port 1 received during the control The number of frames correctly forwarded to test port 1 during
portion of the test. This number will include those frames which are the test portion of the test. Received frames MUST have the
Spanning tree frames. For a normal test iteration, this number SHOULD correct destination MAC address and SHOULD match a signature
be equal to the number of frames transmitted by port 2 during the field. For a passing test iteration, this number should be equal
control phase. to the number of frames transmitted by port 2.
-- the number of frames that test port 1 received during the control The flood count on port 1 during the test portion of each test.
phase not including Spanning Tree or other non test generated frames. If the number is non-zero, this is an indication of the DUT/SUT
In all cases, this number SHOULD be equal to the number of frames flooding a frame in which the destination address is not in the
transmitted by port 2 during the control phase of the test. address table.
-- the number of frames test port 3 received during the control The flood count on port 3. If the value is not zero, then this
phase indicates that for that test iteration, the DUT/SUT could not
of the test. If the value is not zero, then this indicates that for determine the proper destination port for that many frames. In
that test iteration, the DUT/SUT could not determine the proper other words, the DUT/SUT flooded the frame to all ports since its
destination address table was full.
port for that many frames. In other words, the DUT/SUT flooded the
frame to
all ports since its address table was full.
5.10 Address Learning Rate 5.10 Address Learning Rate
Objective: 5.10.1 Objective
Once the maximum number of addresses supported per port by the To determine the rate of address learning of a LAN switching device
DUT/SUT is as defined in RFC 2285, section 3.8.2.
known, the addressing learning rate (the rate at which the DUT/SUT
learns
these addresses) can be determined.
Procedure: 5.10.2 Setup Parameters
The following parameters MUST be defined. Each variable is
configured with the following considerations.
Age Time - The maximum time that a DUT/SUT will keep a learned
address in its forwarding table.
Initial Addresses Learning Rate - The starting rate at which new
addresses are offered to the DUT/SUT to be learned.
Number of Addresses - The number of addresses that the DUT/SUT must
learn. The number MUST be between 1 and the maximum number
supported by the implementation. It is recommended no to exceed
the address caching capacity found in section 5.9
5.10.3 Procedure
The aging time of the DUT/SUT MUST be known. The aging time MUST be
longer than the time necessary to produce frames at the specified
rate. If a low frame rate is used for the test, then it may be
possible that sending a large amount of frames may actually take
longer than the aging time.
This test SHOULD at a minimum be performed in a three-port
configuration as described below.
This test MUST consist of a multiple of three ports. Three ports
are REQUIRED and MAY be expanded to fully utilized the DUT/SUT in
increments of three. Each group of three will contain a test
block as described in section 5.9.
An algorithm similar to the one used to determine address caching An algorithm similar to the one used to determine address caching
capacity can be used to determine the address learning rate. This capacity can be used to determine the address learning rate. This
test iterates the rate at which address learning frames are offered test iterates the rate at which address learning frames are offered
by the test device connected to the DUT/SUT. It is recommended to by the test device connected to the DUT/SUT. It is recommended to
set set the number of addresses offered to the DUT/SUT in this test to
the number of addresses offered to the DUT/SUT in this test to the the maximum caching capacity.
maximum caching capacity. However, the address learning rate might
be
determined for different numbers of addresses but in each test run,
the number MUST remain constant.
Initializing the forwarding rate primes the binary search algorithm The address learning rate might be determined for different numbers
and can help to shorten the overall test duration. of addresses but in each test run, the number MUST remain constant
and SHOULD be equal to or less than the maximum address caching
capacity.
A third port on the DUT/SUT MUST listen for flooded frames. 5.10.4 Measurements
In this test, the forwarding rate SHOULD be varied until a rate is Whether the offered addresses per port was successful forwarded
found that is the threshold for the rate supported by the DUT/SUT. It without flooding at the offered learning rate.
may be useful to pick a value slightly higher than the advertised
forwarding rate.
Reporting format: 5.10.5 Reporting format
To be done. After the test is run, results for each iteration SHOULD be displayed
in a table:
Section 6. Security Considerations 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 test port number 2.
This SHOULD match the number of addresses used for the test
iteration. Test frames are the frames sent with varying
destination addresses to confirm that the DUT/SUT has learned
all of the addresses for each test iteration.
The flood count on port 2 during the test portion of each test.
If the number is non-zero, this is an indication of the DUT/SUT
flooding a frame in which the destination address is not in the
address table.
The number of frames correctly forwarded to test port 1 during
the test portion of the test. Received frames MUST have the
correct destination MAC address and SHOULD match a signature
field. For a passing test iteration, this number should be equal
to the number of frames transmitted by port 2.
The flood count on port 1 during the test portion of each test.
If the number is non-zero, this is an indication of the DUT/SUT
flooding a frame in which the destination address is not in the
address table.
The flood count on port 3. If the value is not zero, then this
indicates that for that test iteration, the DUT/SUT could not
determine the proper destination port for that many frames. In
other words, the DUT/SUT flooded the frame to all ports since its
address table was full.
6. Security Considerations
This document does not yet address Security Considerations. This document does not yet address Security Considerations.
Section 7. Authors' Address 7. Authors' Address
Robert Mandeville Robert Mandeville
European Network Laboratories (ENL) European Network Laboratories (ENL)
2, rue Helene Boucher 2, rue Helene Boucher
87286 Guyancourt Cedex 87286 Guyancourt Cedex
France France
Phone: + 33 1 39 44 12 05 Phone: + 33 1 39 44 12 05
EMail: bob@enl.net EMail: bob@enl.net
Judy Keene Jerry Perser
Netcom Systems Netcom Systems
20550 Nordhoff St. 20550 Nordhoff St.
Chatsworth, CA 91311 Chatsworth, CA 91311
USA USA
Phone: +1 818 700 5100 Phone: +1 818 700 5100
Email: judy_keene@netcomsystems.com Email: jerry_perser@netcomsystems.com
Appendix A: Calculating the Interburst Gap Appendix A: Formulas
IBG is defined in RFC 2285 as a function of maximum media rate (also A.1 Calculating the InterBurst Gap
known as line rate), the length of the frames in the bursts with the
preamble and the interframe gap (IFG), the number of frames in the
bursts,
and the intended load.
Using the burst size, frame size and the load per port, the IBG can IBG is defined in RFC 2285 as the interval between two bursts. To
be achieve a desired load, the follow Input Parameter need to be
calculated: defined:
Burst size * ((preamble 64 + (frame size * 8 bits) + 96 IFG bit LENGTH - Frame size in bytes including the CRC.
times))
* 1 (for full duplex) or .5 (for half duplex)
(10 bit times equal 1 microsecond)
Example: LOAD - The intended load in percent. Range is 0 to 100.
Burst size = 24 BURST - The number of frames in the burst (integer value).
Frame size = 64
24 * (64 + 64*8 + 96) = 24 * (672) = 16,128 bit/times = SPEED - media's speed in bits/sec
1612.8 us IBG Ethernet is 10,000,000 bits/sec
Fast Ethernet is 100,000,000 bits/sec
Gigabit Ethernet is 1,000,000,000 bits/sec
In half duplex mode, exactly half of the target load SHOULD be sent DUPLEX - A constant to adjust the transmit rate for full or half
to each of the ports under test. For example, with a 100% load of duplex mode. In full duplex the value is 100, in half
64-byte frames, the target load for each port under test is 7440 duplex the value is 200.
frames received per second and 7440 frames transmitted per second
(for 10Mbps Ethernet).
Recommended characteristic values for burst size are: IFG - A constant 96 bits for the minimum interframe gap.
2 15 60 240 930 The IBG (in seconds) can be calculated:
3 16 62 248
4 20 80 310 (DUPLEX/LOAD - 1) * BURST * (IFG + 64 + 8*LENGTH)] + IFG
5 24 93 372 IBG = ----------------------------------------------------------
6 30 120 465 SPEED
8 31 124 496
10 40 155 620 A.2 Calculating the Number of Bursts for the Test Duration
12 48 186 744
The number of burst for the test duration is rounded up to the
nearest
integer number. The follow Input Parameter need to be 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/sec
Ethernet is 10,000,000 bits/sec
Fast Ethernet is 100,000,000 bits/sec
Gigabit Ethernet is 1,000,000,000 bits/sec
IFG - A constant 96 bits for the minimum interframe gap.
IBG - Found in the above formula
DURATION - Test duration in seconds.
An intermediate number of the Burst duration needs to be calculated
first:
IFG*(BURST-1) + BURST*(64 + 8*LENGTH)
TXTIME = -----------------------------------------
SPEED
Number of Burst for the Test Duration (rounded up):
DURATION
#OFBURSTS = --------------
(TXTIME + IBG)
Example:
LENGTH = 64 bytes per frame
LOAD = 100 % offered load
BURST = 24 frames per burst
SPEED = 10 Mbits/sec (Ethernet)
DUPLEX = 200 (half duplex)
DURATION = 10 seconds test
IBG = 1612.8 uS
TXTIME = 1603.2 uS
#OFBURSTS = 3110
 End of changes. 

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