In daily life, surfing the Internet will definitely involve wireless switches, which provide users with exclusive point-to-point connections. The following is my knowledge about the difference between wireless and wired switches, I hope it will help you!
When used in a star structure, it acts as a central node to amplify signals, and ports do not enjoy bandwidth. If it is a 10M switch, the bandwidth of each port is 10M, and each port has its own MAC address. The main functions of the switch include physical addressing, network topology, error checking, frame sequence and flow control.
At present, some high-end switches have some new functions, such as supporting VLAN (Virtual Local Area Network), supporting link aggregation, and some even have the functions of routing and firewall. Switches can not only connect the same type of networks, but also interconnect different types of networks (such as Ethernet and Fast Ethernet).
Nowadays, many switches can provide high-speed connection ports supporting fast Ethernet or FDDI, which can be used to connect other switches in the network or provide extra bandwidth for key servers with large bandwidth occupation. It is a network device with some functions of a router. It can decide where to send the received data, which is faster than the router.
Main differences between wireless switches and hubs
From the above analysis, we can know that the main differences between switches and hubs are divided into four aspects, namely OSI architecture, data transmission mode, bandwidth occupation mode and transmission mode. The difference of OSI architecture is that the hub belongs to the first layer physical layer equipment of OSI, while the switch belongs to the second layer data link layer equipment of OSI.
In other words, the hub only plays the role of synchronization, amplification and shaping in data transmission, and cannot effectively deal with short frames and fragments in data transmission, and cannot guarantee the integrity and correctness of data transmission; The switch can not only synchronize, amplify and shape data transmission, but also filter short frames and fragments.
At present, 80% of local area networks are Ethernet, and hubs or switches are widely used in local area networks. LAN connected by hubs is called shared LAN, and LAN connected by switches is called switched LAN.
Different ways of working, let's talk about the two concepts of * * * sharing and communication in the network. Here, let's make an analogy. It is also a road with 10 lane. If the driving route is not clearly marked for the road, then vehicles can only grab or occupy the road in a disorderly state, which is prone to traffic jams and collisions between opposite vehicles, reducing the capacity.
In order to avoid the above situation, it is necessary to clearly mark the lanes on the road to ensure that each car goes its own way and does not interfere with each other. * * * addiction network is equivalent to the disorder mentioned above. When the number of data and users exceeds a certain limit, it will cause collision and degrade the network performance.
Switched networks avoid the shortcomings of * * * shared networks. The function of switching technology is to send each packet from one port to the destination port independently according to the destination address of the transmission packet, which avoids the collision with other ports and improves the actual throughput of the network.
* * * The main problem of enjoyable Ethernet is that all users * * * enjoy bandwidth, and the actual available bandwidth of each user decreases with the increase of network users. Is this because when the information is busy, there may be multiple users entering at the same time? Fight? A channel is occupied by only one user at a time, so a large number of users are often in the waiting state of monitoring, which causes jitter, stagnation or distortion of signals in the transmission process and seriously affects the performance of the network.
In switched Ethernet, the switch provides a dedicated information channel for each user. Unless two source ports try to send information to the same destination port at the same time, each source port and its respective destination port can communicate at the same time without collision.
The working mechanism of hubs with different working mechanisms is broadcasting. No matter what type of data packets are received from which port, they will be sent to all other ports in the form of broadcast. The network card (NIC) connected to these ports will judge and process the information, and those that meet the requirements will be left for processing, otherwise they will be discarded, which will easily lead to a broadcast storm, and the network performance will be greatly affected when the network is large.
From its working state, the hub is inefficient (sending packets to all ports) and has poor security (all network cards can receive, but non-destination network cards will discard packets). Moreover, only one packet can be processed at a time, and packets appearing in multiple ports at the same time will conflict. Packets are processed serially, which is not suitable for large network backbones.
The switch works completely differently. It analyzes the header information of Ethernet packets (including original MAC address, target MAC address, information length, etc. ), get the target MAC address, look up the address comparison table (the port corresponding to the MAC address) stored in the switch, confirm which port the network card with the MAC address is connected to, and then only send the data packet to the corresponding port, which effectively suppresses the occurrence of broadcast storm.
This is the biggest difference between a switch and a hub. The bandwidth of the backboard for forwarding messages inside the switch is also much larger than the bandwidth of the port, so the messages are in a parallel state with high efficiency, which can meet the requirements of large-scale network environment for parallel processing of a large number of data.
Difference of bandwidth occupation: No matter how many ports there are, all ports share a bandwidth. Only two ports can transmit data at the same time, and the other ports can only wait. At the same time, the hub can only work in half-duplex mode. For wireless switches, each port has its own bandwidth, which fundamentally guarantees the speed of each port.
When two ports work, the work of other ports is not affected, and the switch can work in either half-duplex mode or full-duplex mode. The difference of transmission mode The hub can only transmit in half-duplex mode, because the hub enjoys the transmission medium, so the hub can only transmit one task at a time on the uplink channel, either receiving data or sending data.
The switch transmits data in full duplex mode, so it can receive and send data at the same time, which not only greatly accelerates the speed of data transmission, but also is at least twice as fast as the hub in terms of the throughput of the whole system, because it can receive and send data at the same time, which is actually far more than twice, because the port bandwidth of the switch is generally many times wider than the hub.
For a simple example, let two groups of people transfer a file to each other at the same time, and the time from one person to the other is 1 minute. If a hub is used, it will take 4 minutes. Data is first transmitted from one person to another, and then the other person returns. Then the other group can do the same job, which is 4 minutes. But with the switch, the speed is much faster. In the same case, it only takes 1 minute. ;