Physical and functional features of L3 Switches

At present, layer-3 switches have become very important devices in networking. Here we mainly introduce the physical characteristics and basic knowledge of layer-3 switches. The performance and function tests of this topic evaluation were conducted by the China Laboratory of Personal Computer commissioned the Network Testing Laboratory of the institute of computing technology, Chinese Emy of sciences. In order to objectively and fairly reflect the features of the product, all three layer-3 switches provided for test are tested in three aspects: physical characteristics, functions, and performance.

For this reason, we have jointly discussed and developed a test scheme for horizontal evaluation of layer-3 switches, which includes six aspects: physical characteristics, functional features, routing protocols, switching performance, manageability, and reliability, at the same time, the price per port of the layer-3 switch is also taken into account.

Physical Features

This test is mainly performed in six aspects. The first is the appearance, including whether the indicator is set properly, whether there is a fault indicator and traffic indicator, whether there is a power switch, whether the attachment for rack installation, and whether the instructions are clear and detailed, whether the language is Chinese. The second is port configuration, which includes port number, port type, WAN/MAN port, 10/100 M Adaptive, FDX/HDX adaptive, and optional MDI/MDI-X port, whether the port settings are reasonable. Third, the modular design involves the supported modules, interface types, and scalability. The fourth is stack characteristics. Check whether the switch supports stack and stack capabilities. Then there is the base type, which can be fixed, modular, or mixed. The last is the hot swapping feature: including the connection module, upstream module, fan, power supply and other components.

Features

Focus on the following points:

1. Forwarding type: the forwarding type of a layer-3 switch is divided into store-and-forward and cut-through. By sending a certain number of Consecutive Frames of different sizes to a layer-3 Switch, test the forwarding delay and confirm the forwarding mode from the delay change.

2. filter: The vswitch sets a filter policy. By sending a certain number of corresponding data frames to the vswitch, check whether the vswitch supports Filtering Based on the port and MAC address and illegal frame Filtering from the forwarding result.

3. broadcast reduction: Broadcast storms on vswitches consume a large amount of bandwidth, reducing normal network traffic and significantly affecting network performance. The purpose of broadcast reduction is to effectively eliminate or reduce broadcast storms on the network. By sending a certain number of broadcast frames to the switch, verify whether the layer-3 switch supports broadcast reduction from the forwarding results. In addition to broadcast storms, there are also other types of storms, such as multi-point transfer storms and spofs for unknown MAC addresses.

4. Port trunk: whether porttrunking or other port speed improvement technologies are supported, providing high-speed uplink.

5.802.1d protocol support: most switches support the 802.1d spanning tree (SpanningTree ). The spanning tree technology can detect and eliminate logical loops in the network. Construct a loop manually and test the elimination of the loop.

6. VLAN function: whether to support VLAN, VLAN implementation standards, VLAN setting methods, and cross-device VLAN capabilities.

7. Traffic Control: whether the HDX and FDX traffic control standards are supported.

8. layer-3 switching capability: by sending a certain number of IP packets to the layer-3 Switch, check whether the layer-3 switch supports layer-3 switching from the forwarding result.

9. Protocol Support: whether the IP protocol is supported or whether the IPX protocol is supported

Routing Protocol

Test the support of the two dynamic routing protocols RIP and OSPF commonly used in the LAN and the size of the route address table.

Exchange Performance

The exchange performance mainly includes the throughput, latency, frame drop rate, back-to-back of the four recognized indicators of the test results are shown in the table ). In addition, we also examine the Address Table depth, line-End Blocking, and multi-to-one port transmission capabilities of layer-3 switches.

Manageability

Currently, layer-3 switches generally adopt management methods, including software management through the console, remote management via Telnet, Web management with strong humanization, and smart network management SNMP and RMON ), it mainly tests the support capability of vswitches and whether they are easy to implement. In addition, whether user access control has security measures and how security policies are also tested.

Reliability

It mainly tests how layer-3 switches can avoid faults and how to solve problems after a fault occurs, including whether layer-3 switches have certain redundancy capabilities, does the manufacturer provide related technical support websites, hotlines, and on-site support ), whether the product has passed national mandatory standards, such as electromagnetic radiation standards, various security standards, and considerations and measures for the heat dissipation of layer-3 switches.

Test Environment

The console is a DellLatitudeCPi notebook with a PentiumII processor, 64 MB memory, and Windows 98 operating system. It is connected to SmartBits2000 through the serial port COM1. Run the corresponding test software on the console to control the SmartBits2000 to complete the test.

The test device consists of one SmartBits2000 and two smartbits10. SmartBits2000 can be installed on 20 different types of test card, currently installed with 5 ML-7710 test card and 2 GX-1405B test card, of which the ML-7710 is three layer Ethernet 10 M/100 M) test card, the GX-1405B is a Gigabit Ethernet test card; SmartBit10 and SmartBits2000 connected, scalable SmartBits2000 on the number of test cards, currently each SmartBits10 installed with 10 SX-7410B test card, SX-7410B for Ethernet 10 M/100 M) test card.