Ethernet switch Test

Network Testing helps the development of Ethernet technology to mature, and more detailed tests will also help those who still have doubts about Ethernet technology to build confidence.

Ethernet is evolving from 10 m to 10G, and various technical updates are constantly carried out. Of course, Ethernet's most important device-switch is changing with each passing day. The corresponding testing technology has also undergone major changes, and the content included is more complex. In terms of product cycle, tests on Ethernet switches are divided into research and testing, development and testing, network testing, and service guarantee testing. There are different layers at each stage. The ethernet switch test can also be divided into functional test, protocol consistency test and interoperability test, performance test, security test, and abnormal environment test. The tests here run through all stages of the test, but the ratio of each stage varies.

Function Testing mainly tests the functions of vswitches, including management function testing, maintenance function testing, and technical function testing. Some of these tests must be completed using instruments, some can be done manually. The networking capability test should also be included in the function test. In this test, testers need to put the networking in different scenarios based on the possible application situations of the product, and test its functionality. In a broad sense, functional testing also requires inspection of documents, help, product tags, and accessories attached to the vswitch.

Protocol consistency testing refers to testing the switch's compliance with certain protocols. Generally, it requires an instrument or related consistency software. Generally, the tester splits the Protocol process into several Test cases. By performing the interaction between these Test cases and the tested switch, the tester judges the Protocol compliance. Theoretically, the consistency tester should implement the details of the Protocol as much as possible, but in practice, it often cannot cover all the content of the Protocol. In this case, testers can use the development interfaces provided by the tester to develop new test cases for maximum protocol coverage. The completeness of protocol coverage is the key to the selection of consistency testing products. For L2 switches, tests on the basic Ethernet protocol, spanning tree, and multicast protocol are required. For L3 switches, tests on routing protocols such as RIP, OSPF, and BGP4 are required, devices that support IPv6 also need to test the IPv6 protocol and IPv6 routing protocol, and perform consistency tests. They also need to test the interconnectivity of switches, especially when a new protocol is used.

The performance test of a vswitch must comply with certain test protocols, including RFC 2544/1242 and RFC 2889/2285. RFC 2544/1242 is a traffic test standard for connected network devices. It mainly includes four indicators: throughput, latency, packet loss, and back-to-back. These four indicators are the main indicators for current switch tests, the switch test will correspond to two-layer switch test, three-layer switch test, Static Routing test, Dynamic Routing test, QoS test, etc, all the metrics used in these tests include throughput, latency, and packet loss. Latency is a very important performance indicator and can be further derived from average latency, Maximum/minimum latency, latency distribution, latency changes, and latency jitter. Considering the relationship between latency and packet loss, some new test items have been introduced, such as E-model for voice. RFC 2889/2285 defines the main test indicators for L2 switches, including: forwarding capability, congestion control, MAC address learning rate, MAC Address Table depth, Error Filtering capability, broadcast forwarding capability, broadcast latency, and forwarding pressure. For a layer-3 switch, you need to test the route table capacity RIB or FIB of different routing protocols, route forwarding capacity throughput and latency, route fluctuation capacity packet loss and fluctuation time, and route aggregation time.

More and more users are concerned about the security of vswitches. In the security test, they need to check whether the vswitch has a management security vulnerability, and perform DoS attack tests on vswitches with anti-attack capabilities. In the past, users often cared about the test of switches under normal traffic. In the actual network, various possible data packets may occur, which may cause switch faults in some situations, for example, if an ARP packet with both the source MAC address and the target MAC address as the broadcast address appears in the network, the switch will crash. Although such a packet is a small probability event, the possible failure may be serious. The following methods are used for exception testing: programming with an instrument to simulate possible abnormal environments in the network, and then observing the switch. Some Environmental Simulators can also be used, simulate packet loss, latency, segmentation, and disorder.