Now is the information age. With the advancement of the times, the Internet is an indispensable part of people’s lives. It is usually made up of many different types of computer networks connected to each other. If several computer networks are physically connected and cannot communicate between them, then this “interconnection” has no practical meaning. So when it comes to “interconnection,” it has been suggested that these interconnected computers can communicate, that is, from a functional and logical point of view, computer networks have formed a large computer network called “Internet.” , the Internet.”
Routers, also known as path selectors, are devices that are interconnected at the network layer. It is more complex and more flexible than a bridge. Routers have stronger heterogeneous network interconnection capabilities, and connectivity objects include local area networks and wide area networks. There are two typical router function can, i.e. the data channel and control functions. Data channel functions include forwarding decisions, backplane forwarding, and output link scheduling, which are generally performed by specific hardware; control functions are generally implemented in software, including information exchange with neighboring routers, system configuration, system management, etc.
A switch (Switch) is a network device that is based on MAC (hardware address of the network card) and can complete the function of encapsulating and forwarding data packets. Today’s switches are divided into two layers: Layer 2 switches, Layer 3 switches, or higher layer switches. Layer 3 switches can also have routing capabilities and are faster than the low-end routers. Its main features are one route, multiple forwarding.
Connecting the networks to each other requires the use of some intermediate devices (or intermediate systems) called relay systems. According to the level of the relay system, there are five types of relay systems:
1. The physical layer (that is, the first layer, layer L1 is often said) is a relay system, that is, a repeater.
2. Data link path layer (i.e., a second layer L2 of the layer), i.e. a bridge or bridge.
3. Network layer (Layer 3, Layer L3) relay system, that is, industrial grade 4G router.
4. The bridge of the bridge and industrial grade 4G router combines the functions of a bridge and an industrial grade 4G router.
5. A relay system above the network layer, ie a gateway.
When the relay system is a repeater, it is generally not called a network interconnection, since this is simply to expand a network, and this is still a network. High-level gateways are currently used less because of their complexity. This the general discussion of the interpenetrating network, when connected with the switch and means, are industrial grade interconnected network routers 4G. This article focuses on switches and industrial grade 4G routers and their differences.
For industrial-grade 4G routers and switches, the main differences are reflected in the following aspects:
( 1) Different levels of work
The original switch was working on the data link layer of the OSI/RM open architecture, the second layer, while the industrial 4G router was designed to work at the network layer of the OSI model. Since the switch works in the second layer (data link layer) of OSI, its working principle is relatively simple, and the industrial-grade 4G router works in the third layer (network layer) of OSI, which can get more protocol information, industrial Level 4G routers can make smarter forwarding decisions.
( 2) Different objects are based on data forwarding
Switch using a physical address, or say to determine the destination address of the MAC address forwarding data. And Industrial 4G router is to use different network ID number (i.e., IP address) to determine the data forwarding address. The IP address is implemented in software and describes the network where the device is located. Sometimes the addresses of these Layer 3 are also called protocol addresses or network addresses. The MAC address is usually provided by the hardware, distributed by the network card manufacturer, and has been solidified into the network card, which is generally unchangeable. IP addresses are usually assigned automatically by the network administrator or the system.
( 3) The traditional switch can only divide the collision domain and cannot divide the broadcast domain; the industrial grade 4G router can split the broadcast domain.
Still connected by the switch segment, the broadcast packet will propagate in all segments switches connected to the same broadcast domain, in some cases lead to traffic congestion and security vulnerabilities. Network segments connected to industrial-grade 4G routers are assigned to different broadcast domains, and broadcast data does not pass through industrial-grade 4G routers. Although the switch above the third layer has the VLAN function, the broadcast domain can also be divided, but the sub-broadcast domains cannot communicate with each other, and the communication between them still requires an industrial-grade 4G router.
( 4) Industrial 4G router mention for the firewall service
Industrial-grade 4G routers only forward packets of a specific address, and do not transmit packet transmissions that do not support routing protocols and transmission of unknown destination network packets, thereby preventing broadcast storms.
Switches are generally used for LAN-WAN connections. Switches are attributed to bridges and are data link layer devices. Some switches can also implement Layer 3 switching. Industrial 4G router for the connection between the WAN-WAN can transmit it to resolve network heterosexual groups, acting on the network layer. They simply accept the incoming packet from one line and then forward it to the other. These two lines may belong to different networks and use different protocols. In comparison, industrial industry level 4G router function switch to a more powerful, but the speed is also relatively slow, expensive, the third layer switches both switches wire-speed packet forwarding capability, but also industrial good 4G router control functions, Therefore, it is widely used.
in conclusion
In summary, the switch is typically used in LAN-WAN connection, the switch attributed to the bridge, a data link layer device, and some switches can also be exchanged in the third layer. Industrial-grade 4G routers are used for WAN-WAN connections, which can resolve forwarding packets between heterogeneous networks and act on the network layer. They simply accept the incoming packet from one line and then forward it to the other. These two lines may belong to different networks and use different protocols. In comparison, industrial-grade 4G routers are more powerful than switches.
