(This page is currently Under Construction)

The Level Test Design (LTD) Specification is one of the products of the OPNFV vsperf project. This page provides an overview of the LTD spec in several forms.

1. The LTD Spec and its goals are Summarized in a 20 page Internet Draft
2. Short descriptions of each of the tests in the LTD Spec
3. Example Device Under Test (DUT) Set-ups, called Deployment Scenarios

 o  Throughput.RFC2889.AddressLearningRate 

This test measures the address learning rate of the DUT, in accordance with section 5.8 of RFC 2889. A minimum of 3 DUT ports are required for this test, a learning port where frames first arrive at the DUT, a test port where frames are forwarded and returned to the source, and a monitoring port where the test device listens for flooded or miss-forwarded frames.

A prerequisite for this test is Throughput.RFC2889.AddressCachingCapacity, where the cache capacity is determined and must not be exceeded here.

 o  PacketLatency.InitialPacketProcessingLatency

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.

 o  Throughput.RFC2544.SystemRecoveryTime

 o  Throughput.RFC2544.ResetTime

 o  Throughput.RFC2889.AddressCachingCapacity
 

This test measures the address cache capacity of the DUT, in accordance with section 5.7 of RFC 2889. A minimum of 3 DUT ports are required for this test, a learning port where frames first arrive at the DUT, a test port where frames are forwarded and returned to the source, and a monitoring port where the test device listens for flooded or miss-forwarded frames.

 o  Throughput.RFC2544.PacketLossRatio

This is the fundamental data path speed test for networking devices, assessing the maximum offered load for the DUT under the constraint that no frames or packets are lost. section 26.1 of RFC 2544 specifies the method for this test (earlier sections of RFC 2544 describe the various test conditions). The term "Throughput" refers to the maximum loss-less sending rate after allowing the DUT queues to drain at the end of the trial. We have expanded this test to allow characterizing the sending rate at target loss ratios other than zero, and 10^-7 is the non-zero default. A complete range of loss ratios could be assessed, as described in section 26.3 of RFC 2544.

This test also assesses the average one-way latency for successfully received packets (note that the average may be misleading if the latency distribution is bi-modal). All Latency tests called for deviate from section 26.2 of RFC 2544, and assess the metric more thoroughly.

 o  Throughput.RFC2544.PacketLossRateFrameModification

This test assesses the RFC 2544 Throughput level with additional processes of packet inspection and modification. The Recommended modification is to change or add a VLAN tag, but many more possibilities exist.

Although Throughput.RFC2544.PacketLossRatio is not a prerequisite test, that Throughput level will normally represent an upper bound on Throughput with Frame Modification.

 o  Throughput.RFC2544.BackToBackFrames

This test attempts to characterize the longest "burst" of back-to-back frames that the DUT can process without loss, as per section 26.4 of RFC 2544. This benchmark should be repeated and result consistency examined, as results with physical devices have been unstable in some cases.

 o  Throughput.RFC2889.MaxForwardingRate

When operating beyond the RFC 2544 Throughput level, the DUT may be able to achieve higher a frame rate transmitted on all egress ports, albeit with frame losses occurring. The Maximum Forwarding Rate is sometimes measured between the Throughput level and the Maximum Offered Load (maximum load on all ingress interfaces) when the transmitted frame rate degrades below the Maximum Offered Load. Section 5.1 of RFC 2889 describes this test.

The Throughput.RFC2544.PacketLossRatio is a prerequisite test.

 o  Throughput.RFC2889.ForwardPressure

Section 5.6 of RFC 2889 describes the Forward Pressure test, where the specified limit on Ethernet Inter-Frame Gap (12 octets) is exceeded by sending Frames with 11 octet Inter-Frame Gaps. The Maximum Forwarding Rate is assessed and reported for the Forward Pressure condition.

The Throughput.RFC2889.MaxForwardingRate is a prerequisite test.

 o  Throughput.RFC2889.BroadcastFrameForwarding

 o  RFC2889 Broadcast Frame Latency test

 o  Throughput.RFC2889.ErrorFramesFiltering

 o  Throughput.RFC2889.Soak

 o  Throughput.RFC2889.SoakFrameModification