Type and method of router test
2. Test method
Router testing methods are usually divided into local testing method, distributed testing method, remote testing method and collaborative testing method. Due to space limitations, this article does not introduce the characteristics and scope of application of other test methods, but only lists the most commonly used remote test methods in router testing.
Among them, the control observation point (PCO): is usually composed of two first-in, first-out (FIFO) queues, whose function is similar to a pair of input and output ports, sending commands to one end of the queue and receiving a response signal from the other end of the same queue; the entity under test (IUT): Item Under Test; the lower tester (LT): The test system that interacts with the layer under test through the PCO located at the lower layer of the entity under test is called the lower test system.
3. Test classification
Based on the above test content, router testing can generally be divided into the following categories: functional testing, performance testing, stability and reliability testing, consistency testing, interoperability testing and network management testing.
(I) Functional testing
Router functions can usually be divided into the following aspects.
(1) Interface function: This function is used to connect the router to the network. It can be divided into LAN interface and WAN interface. The LAN interface mainly includes Ethernet, token ring, token bus, FDDI and other network interfaces. The WAN interface mainly includes E1/T1, E3/T3, DS3, universal serial port (convertable into X.21DTE/DCE, V.35DTE/DCE, RS232DTE/DCE, RS449DTE/DCE, EIA530DTE) and other network interfaces.
(2) Communication protocol function: This function is responsible for handling communication protocols, which can include TCP/IP, PPP, X.25, frame relay and other protocols.
(3) Packet forwarding function: This function is mainly responsible for forwarding packets between ports (including logical ports) according to the contents of the routing table and rewrite the link layer packet header information.
(4) Routing information maintenance function: This function is responsible for running the routing protocol and maintaining the routing table. The routing protocol can include RIP, OSPF, BGP and other protocols.
(5) Management and control functions: The router management and control functions include five functions, SNMP proxy function, Telnet server function, local management, remote monitoring and RMON function. The router is controlled and managed through a variety of different ways and allows logging.
(6) Security functions: used to complete packet filtering, address conversion, access control, data encryption, firewall, address allocation and other functions.
The router is not necessary to fully implement the above functions. However, since the router is a network device, there is a minimum function set, and the router must support the functions specified by the minimum function set. Because most functional tests can be covered by interface tests, performance tests, protocol consistency tests and network management tests, router functional tests can generally only verify functions that cannot be covered by other tests. Router function testing generally uses remote testing method.
(II) Performance testing`
Routers are the core equipment of IP networks, and their performance directly affects the network scale, network stability and network scalability of IP networks. Since the IETF does not make special regulations on router performance testing, generally speaking, testing can only be performed in accordance with RFC2544 (Benchmarking Methodology for Network Interconnect Devices). However, different from general simple network interconnection devices, routers should also be equipped with router-specific performance tests during performance testing. For example, the routing table capacity, routing protocol convergence time and other indicators.
Router performance testing should include the following indicators.
(1) Throughput: Test the router packet forwarding capability. It usually refers to the limit of the router forwarding packets per second without packet loss. Generally, the dichotomy method can be used to find this limit point.
(2) Delay: Test the interval between the router's received and forwarding of the packet within the throughput range. The delay test should be repeated 20 times and then its average value should be taken.
(3) Packet loss rate: Test the ratio of packets dropped by the router under different loads to receive packets. Different loads usually refer to the line speed from throughput test to line speed (the maximum rate of packet transmission on the line), and the step length is generally 10% of the line speed.
(4) Back-to-back frame count: The maximum number of packets that the test router can process without packet loss when it receives transmission at the minimum packet interval. This test actually tests the router's cache capability. If the router has line speed capability (throughput = interface media line speed), the test is meaningless.
(5) System recovery time: Test the time when the router resumes normal operation after overloading. The test method can use the time interval between sending a smaller value between 110% throughput and line speed to the router port, and after 60 seconds, the rate drops to 50% and the last packet loss. If the router has line speed capabilities, the test makes no sense.
(6) System reset: Test the time interval between the router from software reset or power off to normal operation. Normal operation means being able to forward data in throughput.
The following factors should be considered when testing the indicators specified in RFC2544 above.
Frame format: It is recommended to test according to the frame format specified by RFC2544; frame length: increment from the minimum frame length to MTU order, for example, 64, 128, 256, 512, 1024, 1280 on Ethernet, 1518 bytes; Authentication receiving frame: Exclude received non-test frames, such as control frames, routing update frames, etc.; Broadcast frame: Verify the impact of broadcast frames on router performance, after the above test, 1% broadcast frame is mixed in the test frame and then test; Management frame: Verify the impact of management frames on router performance, after the above test, one management frame per second is mixed in the test frame and then test; Routing update: routing update, that is, the impact of the next hop port change on performance; Filter: The impact on router performance under the setting of filter conditions, it is recommended to set 25 filter conditions to test; Protocol Address: The effect of the test router on performance when receiving addresses randomly in 256 networks; Bidirectional traffic: Test the effect of the two-way data sent and received by the router port on performance; Multi-port testing: Consider the impact of the full connection distribution of traffic or the non-full connection distribution on performance; Multi-protocol testing: Consider the impact of the router processing multiple protocols on performance at the same time; Mixed packet length: In addition to the incremental packet length recommended by the test, check the impact of the mixed packet length on router performance. RFC2544 does not stipulate the proportion of each packet length in the mixed packet length except for all test packet lengths. The author recommends testing the distribution of each packet length in the actual network. For example, when there are no special application requirements, 60-byte packets 50%, 128-byte packets 10%, 256-byte packets 15%, 512-byte packets 10%, and 1500-byte packets 15%. In addition to the above-mentioned test items recommended by RFC2544, it is also recommended to test the following content.
①Route oscillation: The impact of router oscillation on router forwarding capabilities. The degree of routing oscillation, that is, the number of routes updated per second, can be determined according to network conditions. The routing update protocol can adopt BGP. ②Route table capacity: test the routing table size. Backbone routers usually run BGP and the routing table contains global routing. Generally speaking, more than 100,000 routes are required, and it is recommended to test by using BGP input to export the route count. ③Clock synchronization: Test the internal clock accuracy and synchronization capabilities on a router containing the corresponding ports such as POS ports. ④Protocol convergence time: The time taken to test the route change notification to the entire network. Although this indicator is related to the router's stand-alone performance, it can only be tested on the network and will change due to configuration changes. You can measure the performance of the entire network by checking this metric after the network configuration is completed. The test time should be determined based on the specific project and the test objectives. It is generally believed that the test time should be between 60 seconds and 300 seconds. In addition, you can generally make settings based on user requirements and test targets. Router performance testing can generally use remote testing method.
(III) Consistency testing
Router consistency testing usually uses the "black box" method, and the IUT of the test device is called the "black box". The test system interfaces with the equipment being tested by controlling the observation point PCO.
Different test events are controlled and observed through different PCOs. According to whether their responses comply with the specifications, namely the timing relationship and data matching restrictions, the test results can be divided into three types: pass, failure, and no results. A router is a complex network interconnection device that requires multiple protocols to be implemented at each communication layer. For example, the physical layer and link layer protocols of the corresponding interface, Internet layer protocols such as IP/ICMP, transport layer protocols such as TCP/UDP, application layer protocols such as Telnet/SNMP, and routing protocols such as RIP/OSPF/BGP.
The protocol consistency test should include all protocols implemented by the router. Because the test has many contents and complex tests, important protocols and content testing can be selected in the test. Since backbone network online routers may affect global routing, special attention should be paid to routing protocol consistency testing such as OSPF and BGP protocols in router testing. Since consistency testing can only select limited test cases, it is generally impossible to cover all the contents of the protocol. Therefore, even if the test passes, it is impossible to ensure that the device fully implements all the contents of the protocol, so the best way is to test it in a real environment. Router consistency testing generally uses distributed testing method or remote testing method.
(IV) Interoperability testing
Because the communication protocol and routing protocol are very complex and have many options, routers that implement the same protocol cannot guarantee interoperability and interoperability. And because of the limited consistency testing capabilities, even if the protocol consistency testing is passed, it may not be guaranteed to fully implement the protocol. Therefore, it is necessary to conduct interoperable testing of the devices.
Interoperability testing is actually replacing the instrument used in the consistency testing with devices that need to be interoperable with, selecting some important and typical interconnect configurations, and observing whether the two devices can work normally as expected.
(V) Stability and reliability testing
Since most routers require continuous operation of 24 hours a day and 7 days a week, the stability and reliability of the backbone router as the core Internet device is particularly important. Therefore, users need to understand the stability and reliability of the exposed router.
The stability and reliability of the router are difficult to test. Generally, it can be reached through two ways: (1) The manufacturer calculates the system reliability through the reliability of key components and the degree of backup; (2) The user or manufacturer calculates product stability and reliability through the failure rate of a large number of the same products. Of course, users can also ensure the reliability and stability of the router to a certain extent by requiring the trial run results within a certain period of time.
(VI) Network management testing
Network management test generally tests the management capabilities of network management software on the network and devices on the network. Since the router is the core device of the IP network, the router must test its support for network management. If the router comes with network management software, you can check the configuration management, security management, performance management, accounting management, fault management, topology management and view management functions implemented by the network management software by using the included network management software. If the router does not come with network management software, the router should test the consistency of the SNMP protocol implementation and the degree of implementation of MIB. Since the router needs to implement a lot of MIBs, each MIB contains a lot of content, it is difficult to fully test the MIB implementation. Generally, the router can check the implementation of MIB by detecting important MIB items.
In addition, since the router equipment is very complex and may adopt a variety of interfaces and protocols, the configuration of the instruments used for router testing and the configuration of the instruments must be determined based on the test content and the actual configuration of the router. Generally speaking, the instruments used for router testing can be divided into performance test instruments, protocol test instruments and other types of instruments.
(1) Performance testing instruments mainly test IP packet forwarding capabilities. The most typical ones are NetCom's SmartBit, Angio's Router Tester, etc. Performance testing instruments sometimes require some protocol simulation capabilities, such as simulation of BGP and OSPF.
(2) The protocol test instrument mainly tests the consistency of the router to the protocol implementation. Mainly there are routing protocol consistency testing instruments such as Router Tester of Angio. The instruments used for protocol consistency testing implemented by other protocols such as TCP/IP, ATM, ISDN, SNMP, etc. can use a variety of dedicated or general-purpose instruments.
(3) Other instruments mainly include some general instruments, such as oscilloscopes, multimeters, rate consumption devices, optical power meters, etc. In the selection of test instruments, the accuracy and error range of the instrument should also be considered. To sum up, the testing of routers is a complex but very important task. Only by studying the testing methods and combining the specific testing situation, formulating the correct test plan, selecting the appropriate testing instrument, and carefully testing can the testing purpose be achieved.
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Article entry: csh Editor in charge: csh
With the rapid development of the information industry, computer network technology has been widely used, and computer networks have become an indispensable part of modern work and life. As the core device of the computer network, routers have a wide range of applications on the network accordingly. High-end routers have now become enterprise-level equipment to the public's important telecommunications-level equipment online. With the gradual popularity of the Internet and its increasing importance in life, the performance, function, security, reliability and other indicators of routers have become increasingly important. Therefore, it is of importance and necessity to test routers. The router testing specifications are mainly standardized by the following communication industry standards: YD/T1156-
2001 "Router Test Specification - High-end Router"; YD/T1098-2001 "Router Test Specification - Low-end Router". The above standards are formulated according to the following standards: YD/T1097-2001 "Router Equipment Technical Specifications - High-end Routers"; YD/T1096-2001 "Router Equipment Technical Specifications - Low-end Routers".
The test introduction in this article is mainly based on the above-mentioned router testing specifications. However, since the above test specifications are only used as equipment network access testing standards and are an introductory test, we focus on introducing some other test contents added on the above specifications.
1. Purpose and content of the test
A router is a device that enables network interconnection by forwarding data packets. It can support multiple protocols (such as TCP/IP, SPX/IPX, AppleTalk), and can forward data packets at multiple levels (such as data link layer, network layer, and application layer).
The router needs to connect two or more logical ports, at least one physical port. The router determines the output port and the next router address or host address based on the network layer address in the received data packet and the routing table maintained by the router internally, and rewrites the link layer packet header. The routing table must be dynamically maintained to reflect the current network topology. Routers usually dynamically maintain routing tables by exchanging routing information with other routers.
(I) Router classification
The current router classification methods vary. Various classification methods have certain correlations, but are not completely consistent. It can usually be based on router capability classification, structural classification, location classification in the network, functional classification and performance classification. In the formulation of router standards, it is mainly classified according to capabilities, and is divided into high-end routers and low-end routers according to capabilities. Routers with backplane switching capabilities greater than 20Gbit/s and throughput greater than 20Mbit/s are called high-end routers. Routers with switching capabilities below the above data become low-end routers. Correspondingly, router testing specifications are divided into high-end router testing specifications and low-end router testing specifications.
(II) Test purpose and content
By testing the router, you can learn which routers can provide the best performance, the behavior of the router under different loads, the design parameters of the router using the modeled network, whether the router can handle burst traffic, the performance limitations of the router, whether the router can provide different service quality, the impact of different router architectures on functions and performance, the functional characteristics and performance indicators of the router, whether the use of the router affects network security, the consistency of router protocol implementation, and the router reliability and the advantages and disadvantages of router products.
Low-end router equipment testing mainly includes: conventional testing, namely electrical security testing; environmental testing, including high and low temperature, humidity testing and high and low temperature storage testing; physical interface testing, testing the electrical and physical testing of low-end routers that may have interfaces; protocol consistency testing, testing the consistency of protocol implementation; performance testing, testing the main performance of the router; management testing, mainly testing the router's support for network management functions without large items.
High-end router testing mainly includes: interface testing, interface testing that high-end routers may have; ATM protocol testing, testing ATM protocol requirements; PPP protocol testing, testing PPP protocol consistency; IP protocol testing, testing IP protocol consistency; routing protocol testing, testing routing protocol consistency; network management function testing, verifying test gateway functions; performance and QoS testing, testing router performance and QoS capability verification; network synchronization testing, testing equipment synchronization timing capabilities; reliability testing, verifying equipment reliability; power supply testing, testing the power consumption of the whole machine, etc.; environmental testing, including high and low temperature, humidity testing and high and low temperature storage testing.
The above two test specifications have different organizational arrangements due to different drafting units and drafting time. In addition to the above tests, it is recommended to consider the test items listed below in the test. (1) Functional testing: It mainly verifies whether the product has every function of the design. (2) Stability and reliability testing: Generally, the method of increasing load is adopted to evaluate and analyze the operating capabilities of the equipment under long and high load conditions. (3) Interoperability testing: Different network products must be interoperable. Interoperability tests examine whether a network product can work well in a network environment where multiple network products from different manufacturers are interconnected, such as verifying the interoperability of routers and Cisco products, and the interoperability of switches with Cisco, 3Com, Lucent, Intel, etc.
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Article entry: csh Editor in charge: csh