Comprehensive comparison of layer-3 switches, routers, and hubs

Layer-3 switches and routers are widely used in various fields, including hub hubs. The most fundamental difference between a layer-3 Switch and a router is that a layer-3 Switch also has a "routing" function, which is consistent with the routing function of a traditional router. However, layer-3 switches and routers are quite essentially different.

1. Different Main Functions

Both layer-3 switches and routers have the routing function. The main function of the router is the routing function, but its other functions are only its additional functions. A layer-3 switch is still a switch with some basic routing functions. Its main function is data exchange. That is to say, it provides both data exchange and routing, but its main function is data exchange. The router only has the main function of routing forwarding.

2. The main application environments are different.

A layer-3 switch connects to a simple lan, while a router connects to a complex network. The routing function of a layer-3 switch is generally simple, and the routing path is far less complex than that of a router. It mainly deals with simple LAN connections. It is mainly used in LAN or provides fast data exchange function to meet the characteristics of frequent LAN data exchange applications.

The router is different. It is designed to meet different types of network connections. Its routing function is more reflected in the interconnection between different types of networks, for example, the connection between the LAN and WAN and the connection between networks of different protocols. Therefore, routers are mainly used between different types of networks. Its main function is route forwarding. It is its ultimate goal to solve the connection of various complex routing paths. Therefore, the router's routing function is usually very powerful, not only applicable to LAN with the same protocol, it is more suitable for LAN and WAN networks with different protocols. Its advantage lies in the selection of the best routing, load balancing, link backup, and the exchange of routing information with other networks. In order to connect to various types of networks, vro interfaces are rich in types, while layer-3 switches are generally only LAN interfaces of the same type, which is very simple.

3. Performance is different

Technically speaking, there are significant differences between a router and a layer-3 Switch in Packet Exchange operations. Generally, a vro performs Packet Exchange by a microprocessor-based software routing engine, while a layer-3 Switch performs Packet Exchange through hardware. After a layer-3 switch routes the first data stream, it will generate a ing table between the MAC address and IP address. When the same data stream passes through again, the table is directly routed from the second layer instead of the second layer, which eliminates the network delay caused by router selection and improves the efficiency of packet forwarding. At the same time, the routing lookup of a layer-3 switch is for data streams. It uses the caching technology and ASIC Technology to easily implement it. Therefore, it can greatly save costs and achieve fast forwarding. Vro's forwarding adopts the longest matching method, which is complicated. It is usually implemented using software, and the forwarding efficiency is low.

For this reason, compared with the overall performance, the performance of the layer-3 switch is far better than that of the router, which is very suitable for LAN with frequent data exchanges, however, its data packet forwarding efficiency is far lower than that of layer-3 switches. It is more suitable for interconnection between different types of networks with less frequent data exchanges, such as the interconnection between local networks and the Internet. If a router, especially a high-end router, is used in a LAN, it is a waste in terms of its powerful routing function), and it cannot meet the communication performance of the LAN.

Difference between a hub and a vswitch

1. hub) is a form of repeater. It works on the physical layer, just like a repeater, and is often used for Bidirectional Forwarding of physical signals between two network nodes. Completes signal replication, adjustment, and amplification. The difference is that the hub can provide multi-port services. During data transmission. Because of blocking, latency, and other reasons. Short frames, fragments, and so on will appear. From the ISO physical system, we can see that the hub is a physical device. The physical layer provides a basic mechanism for binary data bit encoding to be sent to the physical media) and decoding to receive data from the physical media. The physical layer also defines the physical connection mechanism with the media, but not the media itself. Therefore, the hub only synchronizes, scales up, and shaping data. However, fragments cannot be processed for short frames in the data process.

2. SWITCH) similar to hub, it can connect two LAN segments. It works on the data link layer and can filter frames. The source address and destination address of the SWITCH detection frame. If it is in the same network segment, it is not forwarded. If not in the same network segment, the frame is forwarded to another network segment.

The SWITCH works on the data link layer. This layer provides a Frame consisting of information bits). A Frame consists of a header or packet header containing the Starting Sign, addressing information, and a 32-bit cyclic rst code CRC for the LAN). CRC ensures the integrity of frames when the information bit passes through the physical media. The data link layer also provides link management. For Ethernet, frames are transmitted when the channel is idle and the frames are stopped when a conflict is detected. In the ring. Frames are transmitted when a free token is received. Therefore, the switch can not only synchronize, zoom in, and shaping data, but also effectively filter short frames and fragments. The Hub uses the shared bandwidth method, while the switch uses the exclusive bandwidth.