2. VSPERF LEVEL TEST DESIGN (LTD)

2.1. Introduction

The intention of this Level Test Design (LTD) document is to specify the set of tests to carry out in order to objectively measure the current characteristics of a virtual switch in the Network Function Virtualization Infrastructure (NFVI) as well as the test pass criteria. The detailed test cases will be defined in details-of-LTD, preceded by the doc-id and the scope.

This document is currently in draft form.

2.2. Document identifier

The document id will be used to uniquely identify versions of the LTD. The format for the document id will be: OPNFV_vswitchperf_LTD_REL_STATUS, where by the status is one of: draft, reviewed, corrected or final. The document id for this version of the LTD is: OPNFV_vswitchperf_LTD_Brahmaputra_REVIEWED.

2.3. Scope

The main purpose of this project is to specify a suite of performance tests in order to objectively measure the current packet transfer characteristics of a virtual switch in the NFVI. The intent of the project is to facilitate testing of any virtual switch. Thus, a generic suite of tests shall be developed, with no hard dependencies to a single implementation. In addition, the test case suite shall be architecture independent.

The test cases developed in this project shall not form part of a separate test framework, all of these tests may be inserted into the Continuous Integration Test Framework and/or the Platform Functionality Test Framework - if a vSwitch becomes a standard component of an OPNFV release.

2.5. Features to be tested

Characterizing virtual switches (i.e. Device Under Test (DUT) in this document) includes measuring the following performance metrics:

  • Throughput
  • Packet delay
  • Packet delay variation
  • Packet loss
  • Burst behaviour
  • Packet re-ordering
  • Packet correctness
  • Availability and capacity of the DUT

2.6. Test identification

The following tests aim to determine the maximum forwarding rate that can be achieved with a virtual switch. The list is not exhaustive but should indicate the type of tests that should be required. It is expected that more will be added.

Title: RFC 2544 X% packet loss ratio Throughput and Latency Test

Prerequisite Test: N/A

Priority:

Description:

This test determines the DUT’s maximum forwarding rate with X% traffic loss for a constant load (fixed length frames at a fixed interval time). The default loss percentages to be tested are: - X = 0% - X = 10^-7%

Note: Other values can be tested if required by the user.

The selected frame sizes are those previously defined under Default Test Parameters. The test can also be used to determine the average latency of the traffic.

Under the RFC2544 test methodology, the test duration will include a number of trials; each trial should run for a minimum period of 60 seconds. A binary search methodology must be applied for each trial to obtain the final result.

Expected Result: At the end of each trial, the presence or absence of loss determines the modification of offered load for the next trial, converging on a maximum rate, or RFC2544 Throughput with X% loss. The Throughput load is re-used in related RFC2544 tests and other tests.

Metrics Collected:

The following are the metrics collected for this test:

  • The maximum forwarding rate in Frames Per Second (FPS) and Mbps of the DUT for each frame size with X% packet loss.
  • The average latency of the traffic flow when passing through the DUT (if testing for latency, note that this average is different from the test specified in Section 26.3 of RFC2544).
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Title: RFC 2544 X% packet loss Throughput and Latency Test with packet modification

Prerequisite Test: N/A

Priority:

Description:

This test determines the DUT’s maximum forwarding rate with X% traffic loss for a constant load (fixed length frames at a fixed interval time). The default loss percentages to be tested are: - X = 0% - X = 10^-7%

Note: Other values can be tested if required by the user.

The selected frame sizes are those previously defined under Default Test Parameters. The test can also be used to determine the average latency of the traffic.

Under the RFC2544 test methodology, the test duration will include a number of trials; each trial should run for a minimum period of 60 seconds. A binary search methodology must be applied for each trial to obtain the final result.

During this test, the DUT must perform the following operations on the traffic flow:

  • Perform packet parsing on the DUT’s ingress port.
  • Perform any relevant address look-ups on the DUT’s ingress ports.
  • Modify the packet header before forwarding the packet to the DUT’s egress port. Packet modifications include:
    • Modifying the Ethernet source or destination MAC address.
    • Modifying/adding a VLAN tag. (Recommended).
    • Modifying/adding a MPLS tag.
    • Modifying the source or destination ip address.
    • Modifying the TOS/DSCP field.
    • Modifying the source or destination ports for UDP/TCP/SCTP.
    • Modifying the TTL.

Expected Result: The Packet parsing/modifications require some additional degree of processing resource, therefore the RFC2544 Throughput is expected to be somewhat lower than the Throughput level measured without additional steps. The reduction is expected to be greatest on tests with the smallest packet sizes (greatest header processing rates).

Metrics Collected:

The following are the metrics collected for this test:

  • The maximum forwarding rate in Frames Per Second (FPS) and Mbps of the DUT for each frame size with X% packet loss and packet modification operations being performed by the DUT.
  • The average latency of the traffic flow when passing through the DUT (if testing for latency, note that this average is different from the test specified in Section 26.3 of RFC2544).
  • The RFC5481 PDV form of delay variation on the traffic flow, using the 99th percentile.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Title: RFC 2544 Throughput and Latency Profile

Prerequisite Test: N/A

Priority:

Description:

This test reveals how throughput and latency degrades as the offered rate varies in the region of the DUT’s maximum forwarding rate as determined by LTD.Throughput.RFC2544.PacketLossRatio (0% Packet Loss). For example it can be used to determine if the degradation of throughput and latency as the offered rate increases is slow and graceful or sudden and severe.

The selected frame sizes are those previously defined under Default Test Parameters.

The offered traffic rate is described as a percentage delta with respect to the DUT’s RFC 2544 Throughput as determined by LTD.Throughput.RFC2544.PacketLoss Ratio (0% Packet Loss case). A delta of 0% is equivalent to an offered traffic rate equal to the RFC 2544 Maximum Throughput; A delta of +50% indicates an offered rate half-way between the Maximum RFC2544 Throughput and line-rate, whereas a delta of -50% indicates an offered rate of half the RFC 2544 Maximum Throughput. Therefore the range of the delta figure is natuarlly bounded at -100% (zero offered traffic) and +100% (traffic offered at line rate).

The following deltas to the maximum forwarding rate should be applied:

  • -50%, -10%, 0%, +10% & +50%

Expected Result: For each packet size a profile should be produced of how throughput and latency vary with offered rate.

Metrics Collected:

The following are the metrics collected for this test:

  • The forwarding rate in Frames Per Second (FPS) and Mbps of the DUT for each delta to the maximum forwarding rate and for each frame size.
  • The average latency for each delta to the maximum forwarding rate and for each frame size.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.
  • Any failures experienced (for example if the vSwitch crashes, stops processing packets, restarts or becomes unresponsive to commands) when the offered load is above Maximum Throughput MUST be recorded and reported with the results.

Title: RFC 2544 System Recovery Time Test

Prerequisite Test LTD.Throughput.RFC2544.PacketLossRatio

Priority:

Description:

The aim of this test is to determine the length of time it takes the DUT to recover from an overload condition for a constant load (fixed length frames at a fixed interval time). The selected frame sizes are those previously defined under Default Test Parameters, traffic should be sent to the DUT under normal conditions. During the duration of the test and while the traffic flows are passing though the DUT, at least one situation leading to an overload condition for the DUT should occur. The time from the end of the overload condition to when the DUT returns to normal operations should be measured to determine recovery time. Prior to overloading the DUT, one should record the average latency for 10,000 packets forwarded through the DUT.

The overload condition SHOULD be to transmit traffic at a very high frame rate to the DUT (150% of the maximum 0% packet loss rate as determined by LTD.Throughput.RFC2544.PacketLossRatio or line-rate whichever is lower), for at least 60 seconds, then reduce the frame rate to 75% of the maximum 0% packet loss rate. A number of time-stamps should be recorded: - Record the time-stamp at which the frame rate was reduced and record a second time-stamp at the time of the last frame lost. The recovery time is the difference between the two timestamps. - Record the average latency for 10,000 frames after the last frame loss and continue to record average latency measurements for every 10,000 frames, when latency returns to within 10% of pre-overload levels record the time-stamp.

Expected Result:

Metrics collected

The following are the metrics collected for this test:

  • The length of time it takes the DUT to recover from an overload condition.
  • The length of time it takes the DUT to recover the average latency to pre-overload conditions.

Deployment scenario:

  • Physical → virtual switch → physical.

Title: RFC2544 Back To Back Frames Test

Prerequisite Test: N

Priority:

Description:

The aim of this test is to characterize the ability of the DUT to process back-to-back frames. For each frame size previously defined under Default Test Parameters, a burst of traffic is sent to the DUT with the minimum inter-frame gap between each frame. If the number of received frames equals the number of frames that were transmitted, the burst size should be increased and traffic is sent to the DUT again. The value measured is the back-to-back value, that is the maximum burst size the DUT can handle without any frame loss. Please note a trial must run for a minimum of 2 seconds and should be repeated 50 times (at a minimum).

Expected Result:

Tests of back-to-back frames with physical devices have produced unstable results in some cases. All tests should be repeated in multiple test sessions and results stability should be examined.

Metrics collected

The following are the metrics collected for this test:

  • The average back-to-back value across the trials, which is the number of frames in the longest burst that the DUT will handle without the loss of any frames.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Deployment scenario:

  • Physical → virtual switch → physical.

Title: RFC 2889 X% packet loss Max Forwarding Rate Soak Test

Prerequisite Test LTD.Throughput.RFC2544.PacketLossRatio

Priority:

Description:

The aim of this test is to understand the Max Forwarding Rate stability over an extended test duration in order to uncover any outliers. To allow for an extended test duration, the test should ideally run for 24 hours or, if this is not possible, for at least 6 hours. For this test, each frame size must be sent at the highest Throughput rate with X% packet loss, as determined in the prerequisite test. The default loss percentages to be tested are: - X = 0% - X = 10^-7%

Note: Other values can be tested if required by the user.

Expected Result:

Metrics Collected:

The following are the metrics collected for this test:

  • Max Forwarding Rate stability of the DUT.
    • This means reporting the number of packets lost per time interval and reporting any time intervals with packet loss. The RFC2889 Forwarding Rate shall be measured in each interval. An interval of 60s is suggested.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.
  • The RFC5481 PDV form of delay variation on the traffic flow, using the 99th percentile.

Title: RFC 2889 Max Forwarding Rate Soak Test with Frame Modification

Prerequisite Test: LTD.Throughput.RFC2544.PacketLossRatioFrameModification (0% Packet Loss)

Priority:

Description:

The aim of this test is to understand the Max Forwarding Rate stability over an extended test duration in order to uncover any outliers. To allow for an extended test duration, the test should ideally run for 24 hours or, if this is not possible, for at least 6 hour. For this test, each frame size must be sent at the highest Throughput rate with 0% packet loss, as determined in the prerequisite test.

During this test, the DUT must perform the following operations on the traffic flow:

  • Perform packet parsing on the DUT’s ingress port.
  • Perform any relevant address look-ups on the DUT’s ingress ports.
  • Modify the packet header before forwarding the packet to the DUT’s egress port. Packet modifications include:
    • Modifying the Ethernet source or destination MAC address.
    • Modifying/adding a VLAN tag (Recommended).
    • Modifying/adding a MPLS tag.
    • Modifying the source or destination ip address.
    • Modifying the TOS/DSCP field.
    • Modifying the source or destination ports for UDP/TCP/SCTP.
    • Modifying the TTL.

Expected Result:

Metrics Collected:

The following are the metrics collected for this test:

  • Max Forwarding Rate stability of the DUT.
    • This means reporting the number of packets lost per time interval and reporting any time intervals with packet loss. The RFC2889 Forwarding Rate shall be measured in each interval. An interval of 60s is suggested.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.
  • The RFC5481 PDV form of delay variation on the traffic flow, using the 99th percentile.

Title: RFC 6201 Reset Time Test

Prerequisite Test: N/A

Priority:

Description:

The aim of this test is to determine the length of time it takes the DUT to recover from a reset.

Two reset methods are defined - planned and unplanned. A planned reset requires stopping and restarting the virtual switch by the usual ‘graceful’ method defined by it’s documentation. An unplanned reset requires simulating a fatal internal fault in the virtual switch - for example by using kill -SIGKILL on a Linux environment.

Both reset methods SHOULD be exercised.

For each frame size previously defined under Default Test Parameters, traffic should be sent to the DUT under normal conditions. During the duration of the test and while the traffic flows are passing through the DUT, the DUT should be reset and the Reset time measured. The Reset time is the total time that a device is determined to be out of operation and includes the time to perform the reset and the time to recover from it (cf. RFC6201).

RFC6201 defines two methods to measure the Reset time:

  • Frame-Loss Method: which requires the monitoring of the number of lost frames and calculates the Reset time based on the number of frames lost and the offered rate according to the following formula:

                       Frames_lost (packets)
    Reset_time = -------------------------------------
                   Offered_rate (packets per second)
    
  • Timestamp Method: which measures the time from which the last frame is forwarded from the DUT to the time the first frame is forwarded after the reset. This involves time-stamping all transmitted frames and recording the timestamp of the last frame that was received prior to the reset and also measuring the timestamp of the first frame that is received after the reset. The Reset time is the difference between these two timestamps.

According to RFC6201 the choice of method depends on the test tool’s capability; the Frame-Loss method SHOULD be used if the test tool supports:

  • Counting the number of lost frames per stream.
  • Transmitting test frame despite the physical link status.
whereas the Timestamp method SHOULD be used if the test tool supports:
  • Timestamping each frame.
  • Monitoring received frame’s timestamp.
  • Transmitting frames only if the physical link status is up.

Expected Result:

Metrics collected

The following are the metrics collected for this test:

  • Average Reset Time over the number of trials performed.

Results of this test should include the following information:

  • The reset method used.
  • Throughput in Fps and Mbps.
  • Average Frame Loss over the number of trials performed.
  • Average Reset Time in milliseconds over the number of trials performed.
  • Number of trials performed.
  • Protocol: IPv4, IPv6, MPLS, etc.
  • Frame Size in Octets
  • Port Media: Ethernet, Gigabit Ethernet (GbE), etc.
  • Port Speed: 10 Gbps, 40 Gbps etc.
  • Interface Encapsulation: Ethernet, Ethernet VLAN, etc.

Deployment scenario:

  • Physical → virtual switch → physical.

Title: RFC2889 Forwarding Rate Test

Prerequisite Test: LTD.Throughput.RFC2544.PacketLossRatio

Priority:

Description:

This test measures the DUT’s Max Forwarding Rate when the Offered Load is varied between the throughput and the Maximum Offered Load for fixed length frames at a fixed time interval. The selected frame sizes are those previously defined under Default Test Parameters. The throughput is the maximum offered load with 0% frame loss (measured by the prerequisite test), and the Maximum Offered Load (as defined by RFC2285) is “the highest number of frames per second that an external source can transmit to a DUT/SUT for forwarding to a specified output interface or interfaces”.

Traffic should be sent to the DUT at a particular rate (TX rate) starting with TX rate equal to the throughput rate. The rate of successfully received frames at the destination counted (in FPS). If the RX rate is equal to the TX rate, the TX rate should be increased by a fixed step size and the RX rate measured again until the Max Forwarding Rate is found.

The trial duration for each iteration should last for the period of time needed for the system to reach steady state for the frame size being tested. Under RFC2889 (Sec. 5.6.3.1) test methodology, the test duration should run for a minimum period of 30 seconds, regardless whether the system reaches steady state before the minimum duration ends.

Expected Result: According to RFC2889 The Max Forwarding Rate is the highest forwarding rate of a DUT taken from an iterative set of forwarding rate measurements. The iterative set of forwarding rate measurements are made by setting the intended load transmitted from an external source and measuring the offered load (i.e what the DUT is capable of forwarding). If the Throughput == the Maximum Offered Load, it follows that Max Forwarding Rate is equal to the Maximum Offered Load.

Metrics Collected:

The following are the metrics collected for this test:

  • The Max Forwarding Rate for the DUT for each packet size.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Deployment scenario:

  • Physical → virtual switch → physical. Note: Full mesh tests with multiple ingress and egress ports are a key aspect of RFC 2889 benchmarks, and scenarios with both 2 and 4 ports should be tested. In any case, the number of ports used must be reported.

Title: RFC2889 Forward Pressure Test

Prerequisite Test: LTD.Throughput.RFC2889.MaxForwardingRate

Priority:

Description:

The aim of this test is to determine if the DUT transmits frames with an inter-frame gap that is less than 12 bytes. This test overloads the DUT and measures the output for forward pressure. Traffic should be transmitted to the DUT with an inter-frame gap of 11 bytes, this will overload the DUT by 1 byte per frame. The forwarding rate of the DUT should be measured.

Expected Result: The forwarding rate should not exceed the maximum forwarding rate of the DUT collected by LTD.Throughput.RFC2889.MaxForwardingRate.

Metrics collected

The following are the metrics collected for this test:

  • Forwarding rate of the DUT in FPS or Mbps.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Deployment scenario:

  • Physical → virtual switch → physical.

Title: RFC2889 Error Frames Filtering Test

Prerequisite Test: N/A

Priority:

Description:

The aim of this test is to determine whether the DUT will propagate any erroneous frames it receives or whether it is capable of filtering out the erroneous frames. Traffic should be sent with erroneous frames included within the flow at random intervals. Illegal frames that must be tested include: - Oversize Frames. - Undersize Frames. - CRC Errored Frames. - Dribble Bit Errored Frames - Alignment Errored Frames

The traffic flow exiting the DUT should be recorded and checked to determine if the erroneous frames where passed through the DUT.

Expected Result: Broken frames are not passed!

Metrics collected

No Metrics are collected in this test, instead it determines:

  • Whether the DUT will propagate erroneous frames.
  • Or whether the DUT will correctly filter out any erroneous frames from traffic flow with out removing correct frames.

Deployment scenario:

  • Physical → virtual switch → physical.

Title: RFC2889 Broadcast Frame Forwarding Test

Prerequisite Test: N

Priority:

Description:

The aim of this test is to determine the maximum forwarding rate of the DUT when forwarding broadcast traffic. For each frame previously defined under Default Test Parameters, the traffic should be set up as broadcast traffic. The traffic throughput of the DUT should be measured.

The test should be conducted with at least 4 physical ports on the DUT. The number of ports used MUST be recorded.

As broadcast involves forwarding a single incoming packet to several destinations, the latency of a single packet is defined as the average of the latencies for each of the broadcast destinations.

The incoming packet is transmitted on each of the other physical ports, it is not transmitted on the port on which it was received. The test MAY be conducted using different broadcasting ports to uncover any performance differences.

Expected Result:

Metrics collected:

The following are the metrics collected for this test:

  • The forwarding rate of the DUT when forwarding broadcast traffic.
  • The minimum, average & maximum packets latencies observed.

Deployment scenario:

  • Physical → virtual switch 3x physical. In the Broadcast rate testing, four test ports are required. One of the ports is connected to the test device, so it can send broadcast frames and listen for miss-routed frames.

Title: Modified RFC 2544 X% packet loss ratio Throughput and Latency Test

Prerequisite Test: N/A

Priority:

Description:

This test determines the DUT’s maximum forwarding rate with X% traffic loss for a constant load (fixed length frames at a fixed interval time). The default loss percentages to be tested are: X = 0%, X = 10^-7%

Modified RFC 2544 throughput benchmarking methodology aims to quantify the throughput measurement variations observed during standard RFC 2544 benchmarking measurements of virtual switches and VNFs. The RFC2544 binary search algorithm is modified to use more samples per test trial to drive the binary search and yield statistically more meaningful results. This keeps the heart of the RFC2544 methodology, still relying on the binary search of throughput at specified loss tolerance, while providing more useful information about the range of results seen in testing. Instead of using a single traffic trial per iteration step, each traffic trial is repeated N times and the success/failure of the iteration step is based on these N traffic trials. Two types of revised tests are defined - Worst-of-N and Best-of-N.

Worst-of-N

Worst-of-N indicates the lowest expected maximum throughput for ( packet size, loss tolerance) when repeating the test.

  1. Repeat the same test run N times at a set packet rate, record each result.
  2. Take the WORST result (highest packet loss) out of N result samples, called the Worst-of-N sample.
  3. If Worst-of-N sample has loss less than the set loss tolerance, then the step is successful - increase the test traffic rate.
  4. If Worst-of-N sample has loss greater than the set loss tolerance then the step failed - decrease the test traffic rate.
  5. Go to step 1.

Best-of-N

Best-of-N indicates the highest expected maximum throughput for ( packet size, loss tolerance) when repeating the test.

  1. Repeat the same traffic run N times at a set packet rate, record each result.
  2. Take the BEST result (least packet loss) out of N result samples, called the Best-of-N sample.
  3. If Best-of-N sample has loss less than the set loss tolerance, then the step is successful - increase the test traffic rate.
  4. If Best-of-N sample has loss greater than the set loss tolerance, then the step failed - decrease the test traffic rate.
  5. Go to step 1.

Performing both Worst-of-N and Best-of-N benchmark tests yields lower and upper bounds of expected maximum throughput under the operating conditions, giving a very good indication to the user of the deterministic performance range for the tested setup.

Expected Result: At the end of each trial series, the presence or absence of loss determines the modification of offered load for the next trial series, converging on a maximum rate, or RFC2544 Throughput with X% loss. The Throughput load is re-used in related RFC2544 tests and other tests.

Metrics Collected:

The following are the metrics collected for this test:

  • The maximum forwarding rate in Frames Per Second (FPS) and Mbps of the DUT for each frame size with X% packet loss.
  • The average latency of the traffic flow when passing through the DUT (if testing for latency, note that this average is different from the test specified in Section 26.3 of RFC2544).
  • Following may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system:
  • CPU core utilization.
  • CPU cache utilization.
  • Memory footprint.
  • System bus (QPI, PCI, ...) utilization.
  • CPU cycles consumed per packet.

Title: <tech> Overlay Network RFC 2544 X% packet loss ratio Throughput and Latency Test

NOTE: Throughout this test, four interchangeable overlay technologies are covered by the same test description. They are: VXLAN, GRE, NVGRE and GENEVE.

Prerequisite Test: N/A

Priority:

Description: This test evaluates standard switch performance benchmarks for the scenario where an Overlay Network is deployed for all paths through the vSwitch. Overlay Technologies covered (replacing <tech> in the test name) include:

  • VXLAN
  • GRE
  • NVGRE
  • GENEVE

Performance will be assessed for each of the following overlay network functions:

  • Encapsulation only
  • De-encapsulation only
  • Both Encapsulation and De-encapsulation

For each native packet, the DUT must perform the following operations:

  • Examine the packet and classify its correct overlay net (tunnel) assignment
  • Encapsulate the packet
  • Switch the packet to the correct port

For each encapsulated packet, the DUT must perform the following operations:

  • Examine the packet and classify its correct native network assignment
  • De-encapsulate the packet, if required
  • Switch the packet to the correct port

The selected frame sizes are those previously defined under Default Test Parameters.

Thus, each test comprises an overlay technology, a network function, and a packet size with overlay network overhead included (but see also the discussion at https://etherpad.opnfv.org/p/vSwitchTestsDrafts ).

The test can also be used to determine the average latency of the traffic.

Under the RFC2544 test methodology, the test duration will include a number of trials; each trial should run for a minimum period of 60 seconds. A binary search methodology must be applied for each trial to obtain the final result for Throughput.

Expected Result: At the end of each trial, the presence or absence of loss determines the modification of offered load for the next trial, converging on a maximum rate, or RFC2544 Throughput with X% loss (where the value of X is typically equal to zero). The Throughput load is re-used in related RFC2544 tests and other tests.

Metrics Collected: The following are the metrics collected for this test:

  • The maximum Throughput in Frames Per Second (FPS) and Mbps of the DUT for each frame size with X% packet loss.
  • The average latency of the traffic flow when passing through the DUT and VNFs (if testing for latency, note that this average is different from the test specified in Section 26.3 of RFC2544).
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Title: RFC 2544 X% packet loss ratio match action Throughput and Latency Test

Prerequisite Test: LTD.Throughput.RFC2544.PacketLossRatio

Priority:

Description:

The aim of this test is to determine the cost of carrying out match action(s) on the DUT’s RFC2544 Throughput with X% traffic loss for a constant load (fixed length frames at a fixed interval time).

Each test case requires:
  • selection of a specific match action(s),
  • specifying a percentage of total traffic that is elligible for the match action,
  • determination of the specific test configuration (number of flows, number of test ports, presence of an external controller, etc.), and
  • measurement of the RFC 2544 Throughput level with X% packet loss: Traffic shall be bi-directional and symmetric.

Note: It would be ideal to verify that all match action-elligible traffic was forwarded to the correct port, and if forwarded to an unintended port it should be considered lost.

A match action is an action that is typically carried on a frame or packet that matches a set of flow classification parameters (typically frame/packet header fields). A match action may or may not modify a packet/frame. Match actions include [1]:

  • output : outputs a packet to a particular port.
  • normal: Subjects the packet to traditional L2/L3 processing (MAC learning).
  • flood: Outputs the packet on all switch physical ports other than the port on which it was received and any ports on which flooding is disabled.
  • all: Outputs the packet on all switch physical ports other than the port on which it was received.
  • local: Outputs the packet on the ``local port,’’ which corresponds to the network device that has the same name as the bridge.
  • in_port: Outputs the packet on the port from which it was received.
  • Controller: Sends the packet and its metadata to the OpenFlow controller as a ``packet in’’ message.
  • enqueue: Enqueues the packet on the specified queue within port.
  • drop: discard the packet.
Modifications include [1]:
  • mod vlan: covered by LTD.Throughput.RFC2544.PacketLossRatioFrameModification
  • mod_dl_src: Sets the source Ethernet address.
  • mod_dl_dst: Sets the destination Ethernet address.
  • mod_nw_src: Sets the IPv4 source address.
  • mod_nw_dst: Sets the IPv4 destination address.
  • mod_tp_src: Sets the TCP or UDP or SCTP source port.
  • mod_tp_dst: Sets the TCP or UDP or SCTP destination port.
  • mod_nw_tos: Sets the DSCP bits in the IPv4 ToS/DSCP or IPv6 traffic class field.
  • mod_nw_ecn: Sets the ECN bits in the appropriate IPv4 or IPv6 field.
  • mod_nw_ttl: Sets the IPv4 TTL or IPv6 hop limit field.

Note: This comprehensive list requires extensive traffic generator capabilities.

The match action(s) that were applied as part of the test should be reported in the final test report.

During this test, the DUT must perform the following operations on the traffic flow:

  • Perform packet parsing on the DUT’s ingress port.
  • Perform any relevant address look-ups on the DUT’s ingress ports.
  • Carry out one or more of the match actions specified above.

The default loss percentages to be tested are: - X = 0% - X = 10^-7% Other values can be tested if required by the user. The selected frame sizes are those previously defined under Default Test Parameters.

The test can also be used to determine the average latency of the traffic when a match action is applied to packets in a flow. Under the RFC2544 test methodology, the test duration will include a number of trials; each trial should run for a minimum period of 60 seconds. A binary search methodology must be applied for each trial to obtain the final result.

Expected Result:

At the end of each trial, the presence or absence of loss determines the modification of offered load for the next trial, converging on a maximum rate, or RFC2544Throughput with X% loss. The Throughput load is re-used in related RFC2544 tests and other tests.

Metrics Collected:

The following are the metrics collected for this test:
  • The RFC 2544 Throughput in Frames Per Second (FPS) and Mbps of the DUT for each frame size with X% packet loss.
  • The average latency of the traffic flow when passing through the DUT (if testing for latency, note that this average is different from the test specified in Section 26.3 ofRFC2544).
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

The metrics collected can be compared to that of the prerequisite test to determine the cost of the match action(s) in the pipeline.

Deployment scenario:

  • Physical → virtual switch → physical (and others are possible)
[1] ovs-ofctl - administer OpenFlow switches
[http://openvswitch.org/support/dist-docs/ovs-ofctl.8.txt ]

These tests will measure the store and forward latency as well as the packet delay variation for various packet types through the virtual switch. The following list is not exhaustive but should indicate the type of tests that should be required. It is expected that more will be added.

Title: Initial Packet Processing Latency

Prerequisite Test: N/A

Priority:

Description:

In some virtual switch architectures, the first packets of a flow will take the system longer to process than subsequent packets in the flow. This test determines the latency for these packets. The test will measure the latency of the packets as they are processed by the flow-setup-path of the DUT. There are two methods for this test, a recommended method and a nalternative method that can be used if it is possible to disable the fastpath of the virtual switch.

Recommended method: This test will send 64,000 packets to the DUT, each belonging to a different flow. Average packet latency will be determined over the 64,000 packets.

Alternative method: This test will send a single packet to the DUT after a fixed interval of time. The time interval will be equivalent to the amount of time it takes for a flow to time out in the virtual switch plus 10%. Average packet latency will be determined over 1,000,000 packets.

This test is intended only for non-learning virtual switches; For learning virtual switches use RFC2889.

For this test, only unidirectional traffic is required.

Expected Result: The average latency for the initial packet of all flows should be greater than the latency of subsequent traffic.

Metrics Collected:

The following are the metrics collected for this test:

  • Average latency of the initial packets of all flows that are processed by the DUT.

Deployment scenario:

  • Physical → Virtual Switch → Physical.

Title: Packet Delay Variation Soak Test

Prerequisite Tests: LTD.Throughput.RFC2544.PacketLossRatio (0% Packet Loss)

Priority:

Description:

The aim of this test is to understand the distribution of packet delay variation for different frame sizes over an extended test duration and to determine if there are any outliers. To allow for an extended test duration, the test should ideally run for 24 hours or, if this is not possible, for at least 6 hour. For this test, each frame size must be sent at the highest possible throughput with 0% packet loss, as determined in the prerequisite test.

Expected Result:

Metrics Collected:

The following are the metrics collected for this test:

  • The packet delay variation value for traffic passing through the DUT.
  • The RFC5481 PDV form of delay variation on the traffic flow, using the 99th percentile, for each 60s interval during the test.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

The general aim of these tests is to understand the impact of large flow table size and flow lookups on throughput. The following list is not exhaustive but should indicate the type of tests that should be required. It is expected that more will be added.

Title: RFC 2544 0% loss Flow Scalability throughput test

Prerequisite Test: LTD.Throughput.RFC2544.PacketLossRatio, IF the delta Throughput between the single-flow RFC2544 test and this test with a variable number of flows is desired.

Priority:

Description:

The aim of this test is to measure how throughput changes as the number of flows in the DUT increases. The test will measure the throughput through the fastpath, as such the flows need to be installed on the DUT before passing traffic.

For each frame size previously defined under Default Test Parameters and for each of the following number of flows:

  • 1,000
  • 2,000
  • 4,000
  • 8,000
  • 16,000
  • 32,000
  • 64,000
  • Max supported number of flows.

This test will be conducted under two conditions following the establishment of all flows as required by RFC 2544, regarding the flow expiration time-out:

  1. The time-out never expires during each trial.

2) The time-out expires for all flows periodically. This would require a short time-out compared with flow re-appearance for a small number of flows, and may not be possible for all flow conditions.

The maximum 0% packet loss Throughput should be determined in a manner identical to LTD.Throughput.RFC2544.PacketLossRatio.

Expected Result:

Metrics Collected:

The following are the metrics collected for this test:

  • The maximum number of frames per second that can be forwarded at the specified number of flows and the specified frame size, with zero packet loss.

Title: RFC 2544 0% loss Memory Bandwidth Scalability test

Prerequisite Tests: LTD.Throughput.RFC2544.PacketLossRatio, IF the delta Throughput between an undisturbed RFC2544 test and this test with the Throughput affected by cache and memory bandwidth contention is desired.

Priority:

Description:

The aim of this test is to understand how the DUT’s performance is affected by cache sharing and memory bandwidth between processes.

During the test all cores not used by the vSwitch should be running a memory intensive application. This application should read and write random data to random addresses in unused physical memory. The random nature of the data and addresses is intended to consume cache, exercise main memory access (as opposed to cache) and exercise all memory buses equally. Furthermore:

  • the ratio of reads to writes should be recorded. A ratio of 1:1 SHOULD be used.
  • the reads and writes MUST be of cache-line size and be cache-line aligned.
  • in NUMA architectures memory access SHOULD be local to the core’s node. Whether only local memory or a mix of local and remote memory is used MUST be recorded.
  • the memory bandwidth (reads plus writes) used per-core MUST be recorded; the test MUST be run with a per-core memory bandwidth equal to half the maximum system memory bandwidth divided by the number of cores. The test MAY be run with other values for the per-core memory bandwidth.
  • the test MAY also be run with the memory intensive application running on all cores.

Under these conditions the DUT’s 0% packet loss throughput is determined as per LTD.Throughput.RFC2544.PacketLossRatio.

Expected Result:

Metrics Collected:

The following are the metrics collected for this test:

  • The DUT’s 0% packet loss throughput in the presence of cache sharing and memory bandwidth between processes.
Title: VNF Scalability RFC 2544 X% packet loss ratio Throughput and
Latency Test

Prerequisite Test: N/A

Priority:

Description:

This test determines the DUT’s throughput rate with X% traffic loss for a constant load (fixed length frames at a fixed interval time) when the number of VNFs on the DUT increases. The default loss percentages to be tested are: - X = 0% - X = 10^-7% . The minimum number of VNFs to be tested are 3.

Flow classification should be conducted with L2, L3 and L4 matching to understand the matching and scaling capability of the vSwitch. The matching fields which were used as part of the test should be reported as part of the benchmark report.

The vSwitch is responsible for forwarding frames between the VNFs

The SUT (vSwitch and VNF daisy chain) operation should be validated before running the test. This may be completed by running a burst or continuous stream of traffic through the SUT to ensure proper operation before a test.

Note: The traffic rate used to validate SUT operation should be low enough not to stress the SUT.

Note: Other values can be tested if required by the user.

Note: The same VNF should be used in the “daisy chain” formation. Each addition of a VNF should be conducted in a new test setup (The DUT is brought down, then the DUT is brought up again). An atlernative approach would be to continue to add VNFs without bringing down the DUT. The approach used needs to be documented as part of the test report.

The selected frame sizes are those previously defined under Default Test Parameters. The test can also be used to determine the average latency of the traffic.

Under the RFC2544 test methodology, the test duration will include a number of trials; each trial should run for a minimum period of 60 seconds. A binary search methodology must be applied for each trial to obtain the final result for Throughput.

Expected Result: At the end of each trial, the presence or absence of loss determines the modification of offered load for the next trial, converging on a maximum rate, or RFC2544 Throughput with X% loss. The Throughput load is re-used in related RFC2544 tests and other tests.

If the test VNFs are rather light-weight in terms of processing, the test provides a view of multiple passes through the vswitch on logical interfaces. In other words, the test produces an optimistic count of daisy-chained VNFs, but the cumulative effect of traffic on the vSwitch is “real” (assuming that the vSwitch has some dedicated resources, and the effects on shared resources is understood).

Metrics Collected: The following are the metrics collected for this test:

  • The maximum Throughput in Frames Per Second (FPS) and Mbps of the DUT for each frame size with X% packet loss.
  • The average latency of the traffic flow when passing through the DUT and VNFs (if testing for latency, note that this average is different from the test specified in Section 26.3 of RFC2544).
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Title: VNF Scalability RFC 2544 Throughput and Latency Profile

Prerequisite Test: N/A

Priority:

Description:

This test reveals how throughput and latency degrades as the number of VNFs increases and offered rate varies in the region of the DUT’s maximum forwarding rate as determined by LTD.Throughput.RFC2544.PacketLossRatio (0% Packet Loss). For example it can be used to determine if the degradation of throughput and latency as the number of VNFs and offered rate increases is slow and graceful, or sudden and severe. The minimum number of VNFs to be tested is 3.

The selected frame sizes are those previously defined under Default Test Parameters.

The offered traffic rate is described as a percentage delta with respect to the DUT’s RFC 2544 Throughput as determined by LTD.Throughput.RFC2544.PacketLoss Ratio (0% Packet Loss case). A delta of 0% is equivalent to an offered traffic rate equal to the RFC 2544 Throughput; A delta of +50% indicates an offered rate half-way between the Throughput and line-rate, whereas a delta of -50% indicates an offered rate of half the maximum rate. Therefore the range of the delta figure is natuarlly bounded at -100% (zero offered traffic) and +100% (traffic offered at line rate).

The following deltas to the maximum forwarding rate should be applied:

  • -50%, -10%, 0%, +10% & +50%

Note: Other values can be tested if required by the user.

Note: The same VNF should be used in the “daisy chain” formation. Each addition of a VNF should be conducted in a new test setup (The DUT is brought down, then the DUT is brought up again). An atlernative approach would be to continue to add VNFs without bringing down the DUT. The approach used needs to be documented as part of the test report.

Flow classification should be conducted with L2, L3 and L4 matching to understand the matching and scaling capability of the vSwitch. The matching fields which were used as part of the test should be reported as part of the benchmark report.

The SUT (vSwitch and VNF daisy chain) operation should be validated before running the test. This may be completed by running a burst or continuous stream of traffic through the SUT to ensure proper operation before a test.

Note: the traffic rate used to validate SUT operation should be low enough not to stress the SUT

Expected Result: For each packet size a profile should be produced of how throughput and latency vary with offered rate.

Metrics Collected:

The following are the metrics collected for this test:

  • The forwarding rate in Frames Per Second (FPS) and Mbps of the DUT for each delta to the maximum forwarding rate and for each frame size.
  • The average latency for each delta to the maximum forwarding rate and for each frame size.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.
  • Any failures experienced (for example if the vSwitch crashes, stops processing packets, restarts or becomes unresponsive to commands) when the offered load is above Maximum Throughput MUST be recorded and reported with the results.

The general aim of these tests is to understand the capacity of the and speed with which the vswitch can accommodate new flows.

Title: RFC2889 Address Caching Capacity Test

Prerequisite Test: N/A

Priority:

Description:

Please note this test is only applicable to virtual switches that are capable of MAC learning. The aim of this test is to determine the address caching capacity of the DUT for a constant load (fixed length frames at a fixed interval time). The selected frame sizes are those previously defined under Default Test Parameters.

In order to run this test the aging time, that is the maximum time the DUT will keep a learned address in its flow table, and a set of initial addresses, whose value should be >= 1 and <= the max number supported by the implementation must be known. Please note that if the aging time is configurable it must be longer than the time necessary to produce frames from the external source at the specified rate. If the aging time is fixed the frame rate must be brought down to a value that the external source can produce in a time that is less than the aging time.

Learning Frames should be sent from an external source to the DUT to install a number of flows. The Learning Frames must have a fixed destination address and must vary the source address of the frames. The DUT should install flows in its flow table based on the varying source addresses. Frames should then be transmitted from an external source at a suitable frame rate to see if the DUT has properly learned all of the addresses. If there is no frame loss and no flooding, the number of addresses sent to the DUT should be increased and the test is repeated until the max number of cached addresses supported by the DUT determined.

Expected Result:

Metrics collected:

The following are the metrics collected for this test:

  • Number of cached addresses supported by the DUT.
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Deployment scenario:

  • Physical → virtual switch → 2 x physical (one receiving, one listening).

Title: RFC2889 Address Learning Rate Test

Prerequisite Test: LTD.Memory.RFC2889.AddressCachingCapacity

Priority:

Description:

Please note this test is only applicable to virtual switches that are capable of MAC learning. The aim of this test is to determine the rate of address learning of the DUT for a constant load (fixed length frames at a fixed interval time). The selected frame sizes are those previously defined under Default Test Parameters, traffic should be sent with each IPv4/IPv6 address incremented by one. The rate at which the DUT learns a new address should be measured. The maximum caching capacity from LTD.Memory.RFC2889.AddressCachingCapacity should be taken into consideration as the maximum number of addresses for which the learning rate can be obtained.

Expected Result: It may be worthwhile to report the behaviour when operating beyond address capacity - some DUTs may be more friendly to new addresses than others.

Metrics collected:

The following are the metrics collected for this test:

  • The address learning rate of the DUT.

Deployment scenario:

  • Physical → virtual switch → 2 x physical (one receiving, one listening).

The following tests aim to determine how tightly coupled the datapath and the control path are within a virtual switch. The following list is not exhaustive but should indicate the type of tests that should be required. It is expected that more will be added.

Title: Control Path and Datapath Coupling

Prerequisite Test:

Priority:

Description:

The aim of this test is to understand how exercising the DUT’s control path affects datapath performance.

Initially a certain number of flow table entries are installed in the vSwitch. Then over the duration of an RFC2544 throughput test flow-entries are added and removed at the rates specified below. No traffic is ‘hitting’ these flow-entries, they are simply added and removed.

The test MUST be repeated with the following initial number of flow-entries installed: - < 10 - 1000 - 100,000 - 10,000,000 (or the maximum supported number of flow-entries)

The test MUST be repeated with the following rates of flow-entry addition and deletion per second: - 0 - 1 (i.e. 1 addition plus 1 deletion) - 100 - 10,000

Expected Result:

Metrics Collected:

The following are the metrics collected for this test:

  • The maximum forwarding rate in Frames Per Second (FPS) and Mbps of the DUT.
  • The average latency of the traffic flow when passing through the DUT (if testing for latency, note that this average is different from the test specified in Section 26.3 of RFC2544).
  • CPU and memory utilization may also be collected as part of this test, to determine the vSwitch’s performance footprint on the system.

Deployment scenario:

  • Physical → virtual switch → physical.

The following tests will profile a virtual switch’s CPU and memory utilization under various loads and circumstances. The following list is not exhaustive but should indicate the type of tests that should be required. It is expected that more will be added.

Title: RFC 2544 0% Loss CPU OR Memory Stress Test

Prerequisite Test:

Priority:

Description:

The aim of this test is to understand the overall performance of the system when a CPU or Memory intensive application is run on the same DUT as the Virtual Switch. For each frame size, an LTD.Throughput.RFC2544.PacketLossRatio (0% Packet Loss) test should be performed. Throughout the entire test a CPU or Memory intensive application should be run on all cores on the system not in use by the Virtual Switch. For NUMA system only cores on the same NUMA node are loaded.

It is recommended that stress-ng be used for loading the non-Virtual Switch cores but any stress tool MAY be used.

Expected Result:

Metrics Collected:

The following are the metrics collected for this test:

  • Memory and CPU utilization of the cores running the Virtual Switch.
  • The number of identity of the cores allocated to the Virtual Switch.
  • The configuration of the stress tool (for example the command line parameters used to start it.)
Note: Stress in the test ID can be replaced with the name of the
component being stressed, when reporting the results: LTD.CPU.RFC2544.0PacketLoss or LTD.Memory.RFC2544.0PacketLoss
  1. Throughput tests
  • Test ID: LTD.Throughput.RFC2544.PacketLossRatio
  • Test ID: LTD.Throughput.RFC2544.PacketLossRatioFrameModification
  • Test ID: LTD.Throughput.RFC2544.Profile
  • Test ID: LTD.Throughput.RFC2544.SystemRecoveryTime
  • Test ID: LTD.Throughput.RFC2544.BackToBackFrames
  • Test ID: LTD.Throughput.RFC2889.Soak
  • Test ID: LTD.Throughput.RFC2889.SoakFrameModification
  • Test ID: LTD.Throughput.RFC6201.ResetTime
  • Test ID: LTD.Throughput.RFC2889.MaxForwardingRate
  • Test ID: LTD.Throughput.RFC2889.ForwardPressure
  • Test ID: LTD.Throughput.RFC2889.ErrorFramesFiltering
  • Test ID: LTD.Throughput.RFC2889.BroadcastFrameForwarding
  • Test ID: LTD.Throughput.RFC2544.WorstN-BestN
  • Test ID: LTD.Throughput.Overlay.Network.<tech>.RFC2544.PacketLossRatio
  1. Packet Latency tests
  • Test ID: LTD.PacketLatency.InitialPacketProcessingLatency
  • Test ID: LTD.PacketDelayVariation.RFC3393.Soak
  1. Scalability tests
  • Test ID: LTD.Scalability.Flows.RFC2544.0PacketLoss
  • Test ID: LTD.MemoryBandwidth.RFC2544.0PacketLoss.Scalability
  • LTD.Scalability.VNF.RFC2544.PacketLossProfile
  • LTD.Scalability.VNF.RFC2544.PacketLossRatio
  1. Acivation tests
  • Test ID: LTD.Activation.RFC2889.AddressCachingCapacity
  • Test ID: LTD.Activation.RFC2889.AddressLearningRate
  1. Coupling between control path and datapath Tests
  • Test ID: LTD.CPDPCouplingFlowAddition
  1. CPU and memory consumption
  • Test ID: LTD.Stress.RFC2544.0PacketLoss