Analysis of LAN switch Classification

What is a LAN switch? As well as the working principle and related operation skills of LAN switches, different from the bridge adapter, the forwarding delay of the switch is very small, and the operation is close to the performance of a single LAN, far exceeding the forwarding performance between common Bridging networks.

With the development of network technology, a variety of communication devices have emerged, and switches are one of them. In some technical books or articles, we often see many terms about vswitches. Many of them are directly translated from English and some are named by manufacturers for some purpose. The names of these vswitches are confusing. The following describes the different types of vswitches and analyzes some common terms.

Vswitches include the telephone Switch PBX) and data Switch (Switch). All the vswitches we mentioned below are exponential data switches. We will not discuss traditional telephone 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. The following content is based on LAN switches.

According to the most common classification method, LAN switches can be divided into enterprise-level switches, department-level switches, and working group switches for large-scale applications. When used as a backbone switch, switches that support more than 500 information points for large enterprise applications are enterprise-level switches.

A department-level switch is supported for medium-sized enterprises with less than 300 information points, and a switch with less than 100 information points is a working group-level switch. However, this is not an absolute standard. It is precisely because there is no unified standards for the Division, and there are also Desktop switches and Campus network switches (Campus switches) and other concepts. The following is an overview of the above concepts:

1. Desktop vswitches, which are the most common type of switches, are different from other vswitches in that each port supports few MAC addresses. It is widely used in general offices, small data centers, business departments with concentrated business acceptance, multimedia production centers, website management centers, and other departments. In terms of transmission speed, most modern desktop switches provide multiple ports with 10/100 Mbps adaptive capability.

2. Work Group switches are often used as expansion devices. Most work group switches are directly considered when table switches cannot meet their requirements. 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 Mbps.

3. Department switches are generally no more expensive than workgroup switches, and their port numbers and performance levels are different from those of workgroup switches. A department switch usually has eight to eight ~ 16 ports, usually supporting full-duplex operations on all ports. Their performance is better than the performance of a workgroup switch, and there is a half-duplex pooled bandwidth equal to or greater than the bandwidth of all ports.

4. campus network switches, which are rarely used. They are only used in large networks and are generally used as backbone switches of the network. They have fast data exchange 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.

5. Although enterprise switches are very similar to campus network switches, the biggest difference is that enterprise switches can also access a large chassis. These chassis products usually support many different types of components, such as fast Ethernet and large network relay, FDDI concentrator, licensing ring MAU and router.

Enterprise switches are very useful when building enterprise-level networks, especially for network technologies and previous systems that need to be supported. Chassis-based equipment usually has very powerful management features, so it is very suitable for enterprise network environments. However, the disadvantage of chassis-based equipment is that they all have very high costs.

According to the architecture characteristics, LAN switches are also divided into three types: rack-mounted, fixed configuration with expansion slot, and fixed configuration without expansion slot.

1. rack-mounted switches are slot switches that support different network types, such as Ethernet, fast Ethernet, Gigabit Ethernet, ATM, licensing ring, and FDDI, however, the price is relatively high, and many high-end switches use the rack-mounted structure.

2. A fixed configuration switch with expansion slot is a type of switch with a fixed number of ports and a small number of expansion slots. This type of switch supports a fixed port network, you can also expand other network types to support other types of networks. The prices of these vswitches are centered.

3. A vswitch without fixed expansion slot supports only 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.
In terms 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.

In terms of the ISO/OSI hierarchy, switches can be divided into L2 switches and L3 switches. A layer-2 Switch refers to the layer-2 data link layer switch that traditionally works in the OSI reference model. Its main functions include physical addressing, error verification, frame sequence, and throttling.

A pure second-level solution is the cheapest solution, but it provides minimal control over subnet division and broadcast restrictions. Traditional routers and external switches can also solve this problem, but now the processing speed of the router cannot meet the bandwidth requirements. Therefore, layer-3 switches and Web switches emerged.

A layer-3 switch is a layer-3 Switch with layer-3 routing, it is not simply to overlay the hardware and software of a router device on a LAN switch.

A Web switch provides management, routing, and load balancing transmission for Data Center devices, including Internet servers, firewalls, high-speed buffer servers, and gateways. Unlike traditional network devices, traditional network devices focus on high-speed exchange of individual frames and data packets, while Web switches focus on tracking and processing Web sessions.

In addition to the connections and packet routing provided by the traditional second/third-layer switches, the Web switch can also provide the complete policies lacking by the traditional LAN switches and routers, integrates local and global Server Load balancer, access control, service quality assurance (QoS), bandwidth management, and other management capabilities.

At present, the Web switch has evolved from a purely transport layer Layer-4 device to a layer-7 switch intelligence. Using content or user classification for Web Request redirection is a function of the Web server. However.

The development of Internet transmission and commerce far exceeds the improvement of computer processing capabilities. Unloading content classification to a Web switch balances the infrastructure of the entire website. With the development of technology, there will certainly be more new terms emerging, but as long as you master the principles and have a clear concept, they will not be confused.

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