Methods and applications for testing network and inter-network throughput

"Speed test" can be explained in many ways, in the Internet people's point of view is mainly concerned with the Internet access to network resources. To this end, there are a number of websites that also provide test scripts and services that test the speed of access from visitors to the site. This test method is very simple, but due to many factors, test results are generally only as a specific application to access this particular site (such as: HTTP, FTP) performance evaluation, this kind of content we do not discuss here.

When maintaining a corporate network, we often have to test the transmission of links between networks or networks, and the testing methods often have a variety of choices based on testing purposes. For example, throughput testing as a network installation and maintenance needs to test IP performance across the backbone, WAN, or VPN, and for fault lookup or assistance to other network application analysis of LAN segment, the test methods and requirements are different. Network engineers, network administrators, and telecommunications departments that provide high-speed optical link Ethernet to users in charge of network installation, maintenance and troubleshooting will use throughput and pressurization tests to check link performance at work.

Throughput test

Such tests can solve the following problems:

1. Test end-to-end WAN/LAN throughput

Test IP performance across WAN connections and use to compare the capacity and commitment information rate (CIR) of current WAN links against service level agreements (SLAs)

2. Benchmarking and congestion testing during VPN installation

Test network device pattern, frame size or network rate of the corresponding relationship, for modems, frads, hubs, switches or routers, and other equipment optimization and settings evaluation

Throughput testing requires end-to-end testing by the two ends of the tested link. For the Enterprise network management and maintenance engineers in the end-to-end testing is not necessary to understand or test the physical network, because IP is the host of application services network interconnection platform, such end-to-end link test in the physical network can be wireless network, Routing environments, transparent networks, and even asymmetric networks (such as XDSL and cable modems).

The simplest (and most common and effective) method of throughput testing is to test the access point on the Ethernet network at both ends of the link. The speed at which the received frame is computed on the receiver at the sending end at the specified sending speed at the time of the test. Throughput is a good number of frames received by the receiver/time, the test by changing the frame length, repeat the above test to get the test results at different rates. (Note: Tests can be repeated to determine throughput at different transmission speeds)

One thing to emphasize is that when maintaining a running network, throughput testing must be done online, that is, the existing network service and network connectivity cannot be interrupted, and other network traffic exists during testing. The test results in this case are significant for evaluating the network capabilities of the existing business, and planning to increase the network site and expand the network application.

Test method: End-to-end testing has a lot of testing means and methods, mainly divided into two categories: one is based on PC software testing, the other is the use of specialized testing equipment for testing methods. Usually for large traffic (such as: more than 30Mbps) testing is done mainly using test instruments, because the test instruments are not affected by the operating system, network adapters, device drivers, and configurations, such as pc-based test software, which provide stable, independent and repeatable test results.

Application Case 1: Throughput testing for the corporate network

In this test application, a, B, C, D are the access points that can be selected for testing, and they can form a different link with the tester connected to the hub, and the throughput of these links can be tested to correspond to network bottlenecks and network segments that detect performance problems.

Display of test results

1, part of the test settings to show the parameters: up and down line test rate, test time, frame length, test mode. These parameters are the contents of the predetermined test for the parameter, and the tester can adjust and set the test parameters as needed before the test is carried out.

2, this section of the above, down the way to show the actual transmission rate, the successful transmission of hundred percent and the number of frames lost in the test, this is the tester according to the settings of the test results.

3, the display is the test link parameters: Local and remote IP address, router

4, router hops number.

5, display the current Ethernet access mode of operation.

Application Case 2: Test xDSL link throughput, we have such testing requirements for XDSL test applications, one measure the maximum transmission rate of XDSL on a particular link, and the maximum transmission distance at a specific rate.

Testing requirements for one requirement, there is a need to automatically increment and determine the test function, that is, set the test before the test, the downward start rate and the highest rate of test, and then define an automatic increment of the step, after starting the test rate of the effective transmission rate of more than 95% , a higher rate test is continued until the effective transfer rate is less than 95%, and the maximum transmission rate of the link is determined.

The above test methods for xDSL have been used in foreign countries to the different brands of ADSL modem has been tested, simple and practical, the results are very intuitive evaluation.