Analyze the classification of network switches from different aspects and perspectives

With the development of the communication industry and the advancement of information technology in the national economy, the Ethernet switch market has steadily increased. Ethernet features high performance, high flexibility, relatively simple, and easy to implement. Therefore, Ethernet technology has become the most important LAN networking technology today, and Ethernet switches have become the most popular switches.

In a broad sense, there are two types of switches: WAN switches and LAN switches. WAN switches are mainly used in the telecom field to provide basic communication platforms. LAN switches are used in local networks to connect terminal devices, such as PCs and network printers.

According to the current complex network architecture, network switches are divided into access layer switches, aggregation layer switches, and core layer switches. Among them, all the core layer switches adopt the modular chassis design, and have basically designed the 1000Base-T module. The ethernet switch that supports 1000Base-T in the access layer is basically a fixed-port switch. It uses 10/100 M Port as the main port and provides a 1000Base-T uplink port in a fixed port or expansion slot mode. The 1000Base-T switch of the aggregation layer has two types of designs: the Chassis type and the fixed port type. It can provide multiple 1000Base-T ports, and generally other ports such as 1000Base-X. The access layer and aggregation layer switches form a complete small and medium LAN Solution.

From the perspective of transmission media and transmission speed, LAN switches can be divided into Ethernet switches, Fast Ethernet switches, Gigabit Ethernet switches, FDDI switches, ATM switches, and wildcard ring switches, these switches are applicable to Ethernet, fast Ethernet, FDDI, ATM, and ring-based network.

Enterprise-level switches, department-level switches, and working group switches are available for large-scale applications. The standards of various manufacturers are not completely consistent. Generally, enterprise-level switches are rack-mounted, and department-level switches can be rack-mounted or fixed-configuration switches, the working group-level switches are generally fixed configurations and have simple functions. On the other hand, from the perspective of application scale, enterprise-level switches support large enterprise applications with more than 500 information points as enterprise-level switches, and department-level switches support Switches of medium enterprises with less than 300 information points, switches that support less than 100 information points are working group-level switches.

According to the architecture features, LAN switches are also divided into three types: rack-mounted, fixed configuration with expansion slot, and fixed configuration without expansion slot. A rack-mounted switch is a slot-type switch that provides excellent scalability and supports different network types, such as Ethernet, fast Ethernet, Gigabit Ethernet, ATM, licensing ring, and FDDI, however, the price is relatively high. Many high-end switches use a rack-mounted structure. A fixed-configuration switch with expansion slot is a switch with a fixed port and a small number of expansion slots. This type of switch supports a fixed-port network, you can also extend other network type modules to support other types of networks. The prices of such vswitches are centered. A fixed configuration switch without expansion slot only supports one type of network, which is generally Ethernet. It can be used in LAN in a small enterprise or office environment. It is the cheapest and most widely used.

According to the layer-7 network model of OSI, switches can be divided into layer-2 switches, layer-3 switches, and layer-4 switches until Layer-7 switches. Layer 2 Switches Based on MAC addresses are the most common and used for the network access layer and aggregation layer. Layer-3 switches based on IP addresses and protocols are widely used in the core layer of the network, and a small number of switches are also used in the aggregation layer. Some layer-3 switches also have layer-4 switching function. You can determine the target port based on the protocol port information of the data frame. A layer-4 or above vswitch is called a Content-Type Switch and is mainly used in Internet data centers.

According to the manageability of vswitches, vswitches can be divided into manageable vswitches and unmanageable vswitches. The difference lies in the support for network management protocols such as SNMP and RMON. Manageable switches Facilitate network monitoring and traffic analysis, but the cost is also relatively high. The management switch should be selected for large and medium-sized networks at the aggregation layer. The access layer depends on application requirements, and the core layer switches are all managed switches.

Based on whether the vswitch can be stacked, The vswitch can be divided into two types: stackable vswitch and non-stackable vswitch. A major purpose of stack technology is to increase the port density.

According to the most common classification method, LAN switches can be divided into Desktop Switch, Workgroup Switch, and Campus Switch. Desktop switches are the most common and widely used, especially in general offices, small data centers, and business departments with concentrated business acceptance, multimedia production centers, and website management centers. In terms of transmission speed, most modern desktop switches provide multiple ports with 10/100 M adaptive capability. Working-group switches are often used as expansion devices. Most work-group switches are directly considered when they cannot meet their needs. Although the workgroup switch only has a small number of ports, it supports a large number of MAC addresses and has good scalability. The port transmission speed is basically 100 M. Campus Network switches are rarely used. They are only used in large networks and generally act as backbone switches of networks. They have fast data exchange capabilities and full duplex capabilities, and provide intelligent features such as fault tolerance, it also supports multiple functions such as expansion options and VLAN in layer-3 switching.

According to the switch technology, some people divide the switch into three types: port switch, Frame Switch and primary switch. Different from the bridge adapter, the port switch has a low forwarding latency, and operations are similar to the performance of a single LAN, far exceeding the forwarding performance between common Bridging networks. Port switching technology first appeared in a slot hub. The backboards of these hubs are usually divided into multiple Ethernet segments, which do not need to be connected by bridges or routers. The Ethernet master module is usually allocated to the network segment of a backplane after being inserted. Port switching is used to allocate and balance Ethernet module ports among multiple network segments on the backend. Frame switching is currently the most widely used LAN switching technology. It provides a mechanism for parallel transmission by performing differential segments on Traditional transmission media to reduce conflicting domains and obtain high bandwidth. The ATM technology represents a "good medicine" for network and communication ". ATM uses a cell exchange with a fixed length of 53 bytes. Because the length is fixed, it is easy to implement with hardware. ATM uses dedicated non-differential connections for parallel operation. multiple nodes can be established through a switch at the same time, but the communication capability between each node is not affected. ATM also allows communication between the source and target nodes. The statistical time-division circuit is used in ATM, which can greatly improve the channel utilization. The bandwidth of an ATM can reach 25 Mbps, 155 Mbps, Mbps, or even several Gbit/s.

In fact, from the perspective of applications, switches can be divided into telephone Switch PBX) and data Switch ). Of course, some of the most fashionable voice communication VoIP on data are called "soft switches ".

1. Selection and Use of broadband network switches
2. Describes the categories of vswitches.