Solutions

Ethernet Test Solution

1.      Overview

        The development of Ethernet technology can be divided into five phase: Ethernet, Fast Ethernet, Gigabit Ethernet, 10 Gigabit Ethernet and 40G/100G Ethernet. 10Mbit/s Ethernet and Fast Ethernet have already forestalled the LAN field which covered more than 95% users. But after the developing of Gigabit Ethernet, it has been used wildly in MAN ( metropolitan area network )  due to its unique advantages, such as simple, flexible, cost-effective, expansible, born adaptable to IP technologies and so on With the growing up of 10G Ethernet technologies, Ethernet is turning into WAN(wide area network). 40/100G Ethernet Technology Standard has been published and the technology is becoming more consummate and mature.

        By far, Ethernet has covered every aspect of tabletop, Campus Network, Enterprise Network, Access Network, Metropolitan area network and Backbone Network. As the development and integration of network technology, the applications of Ethernet begin to replace some traditional data transmissions more and more. The changes and developments of Ethernet technologies assure various functions and features of Ethernet. The Ethernet test technologies is developing simultaneity. Generally, it can be included as following test Methodologies:

        1).Forwarding capability tests between equipment and network, including RFC2544/RFC1242   benchmarking test and IP jitter test based on RFC3393;

        2).Multi-streams simulation and statistics tests, including Multi-streams generation and statistics, simulating real network frames and testing the features of network and equipment;

        3).Ethernet BERT test which is mainly used for validating data transmission BERT situation during the transparent transmission of SDH/OTN/DWDM/dark fiber. 

        OPWILL Ethernet test solution supports various speeds from 10M/100M/1000M to 10G.It is generally used in network design, set up, operation and maintenance by network operators and various industries networks. Meanwhile, it is also adopted by network equipment manufacturer to do production test and validation.  

 

2.      Ethernet capability test

2.1 RFC 2544 Benchmark Testing

RFC 2544 (Benchmarking Methodology for Network Interconnect Devices) standard, built by IETF(Internet Engineering Task Force), is a accredited test benchmark. It stipulates a series of test procedures and methods that make service suppliers and users reach an agreement of test operations and results. RFC2544 contains throughput, latency, frame loss, back-to-back tests and each test validated a specific part of SLA; the four main test items can evaluate the capability status of Ethernet.

  RFC 2544 requires the standard frame sizes (64, 128, 256,512, 1024, 1280 and 1518 byte) to be tested for a certain length of time and a certain number of times. This is because all these frame sizes are used in the real network and so the results for each must be known. It costs more frames per time under the same circumstance to transfer small frame sizes .So the small frame is quite important for evaluating Ethernet network.

For duplex Ethernet transmission, the tester needs bi-direction test capability to validate its influence to performance. 

It needs to validate the Ethernet equipment forwarding capability during equipment   certification. Therefore it requires multiport test to find out the full mesh or half mesh influence to performance. In the real Ethernet network test, it is usually enough for end-to-end network transmit test and validation to use two ports.

 

          Throughput Test

          Data throughput is simply the maximum amount of data, which can be transported from source to destination. It is mainly used for validating the maximum transmission rate of DUT or NUT without frame loss. 

          For Ethernet system, absolute maximum throughput rate should be equal to its interface rate. For example, 10Mbit/s, 100Mbit/s, 1000Mbit/s, 10000Mbit/s. Actually, these absolute throughput rates could not be met for different transmission results from different frame sizes. Because of the preamble/SFD and IFG, the smaller the frame is, the lower its transmission efficiency will be.

 

 

          Back-to-Back Test

          Back-to-back test means the maximum forwarding burst frame number without frame loss. The methodology is to send a burst of frames with minimum inter-frame gaps to the DUT/NUT and count the number of frames forwarded by the DUT/NUT. If the frame number received equals to send out, repeat the test by adding frame number until the sent out frame number more than received. Back-to-back test evaluates the maximum number of frame received at line speed of DUT or NUT before frame lost.

  

 

 

 Frame Loss Test

 Frame loss is simply the number of frames that were transmitted successfully from the source but were never received at the destination. It is usually referred as frame loss rate which is expressed as a percentage of the total frames transmitted. There are many reasons make frame lost, such as errors, over-subscription and excessive delay, unsteady network and etc. It is used in evaluating frame lost rate of DUT or NUT in certain throughput condition.                           


       

                 

          Latency Test

 Latency means the total time taken for a frame to travel from source to destination. This total time is the sum of both the processing delays in the network elements and the propagation delay along the transmission medium. The test method is to compare the time stamp between sending and receiving frame in real-time. The loopback latency generally compares the sending frame with loopback frame for adopting the same clock source.    


    

2.2 Multi-Flow Analysis and Test

In actual Ethernet network, it has various services, such as Broadband, VOIP, VOD and etc. The requirements of network capability are different for different services: for example, VOIP needs less latency and jitter of Ethernet transmission. In real network deployment, for guaranteed SLA, it is need setting different priority of different services to share Ethernet bandwidths resources.

In the Ethernet test, it would generate different streams with different priority to simulate different service in real networks.                 


   

     

2.3 Ethernet BERT testing

BERT adopts the principle similar with one in SDH network to validate the bit error rate through analyzing the special frame at the receiver.

Common test modes include various PRBS(Pseudorandom Bit Sequence), user-defined pattern and etc.

 

 

 

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