Brief Introduction to the relationship between a wireless switch and a hub

The repeated startup of a program-controlled switch is an automatic troubleshooting program set up by the switch itself to eliminate certain system faults. Once it is disturbed by the outside world, this will cause repeated startup issues.

1. The main cause of "system restart"

First, restart due to human reasons. Maintenance personnel are mainly responsible for personnel with low technical level and unskilled operations, and artificially inputting Dangerous commands or modifying Bureau data. Inter-Bureau relay lines are interrupted due to natural disasters or human causes and transmission equipment faults, after the system is re-configured, the program becomes chaotic; if the power supply system fails, the system loses power and reloads the system.

Second, restart due to unreasonable network structure and heavy traffic load. The traffic distribution of various cabinets in the main bureau and module Bureau is unbalanced, which exceeds the processing capability of the processor. The number of forwarding and trunk lines that introduce wireless switches is too large and the load is too heavy; when the telephone terminal board and the remote connection board are connected by digital relay, the objects of clock extraction are different.

Third, restart is caused by problems and defects in software and hardware of the programmable wireless switch. There are mainly work software without backup, and automatic switch is not possible if damaged; low processing capability, difficult to withstand excessive traffic, resulting in traffic congestion; low software version, function is not complete, as a result, users, trunk lines, and internal links cannot be automatically detached in a timely manner after the end of long-distance calls or abnormal connection.

2. Main countermeasures to prevent or reduce system restart

First, strengthen technical training and improve duty maintenance capabilities. It is necessary to adopt flexible and diverse methods, strengthen technical training for on-duty maintenance personnel, and improve the service quality. When the system fails, it can be handled in a timely and correct manner, in order to prevent "restart" upgrade and prolong the fault duration, strict implementation of the human-machine command management system and careful use of dangerous man-machine commands should be made; maintenance of system software should be strengthened, and the transcription of post-aid information should be completed in a timely manner.

Second, adjust the network structure to improve the stability of devices. It is necessary to know the traffic volume distribution, adjust the network structure in time, reasonably arrange the actual users on the LIM shelf, evacuate the traffic volume of the system, and compress the total number of calls during busy hours, avoid smooth connection, blocked access, and out-of-control traffic;

It is necessary to strengthen the management and relay maintenance of programmable switches, so as to prevent Switch Equipment and trunk line faults from low access rate, high congestion, and excessive traffic; it is necessary to reduce the number of introduced main bureaus and long-distance trunk lines to minimize the load of the main bureaus. It is necessary to reasonably solve the inter-office digital network synchronization mode, we recommend that you use the "master-slave" synchronization mode to connect the remote connection Bureau to the local terminal Bureau and user-controlled switches connected by digital circuits.

Third, upgrade the version in time to improve the system software functions. During version upgrade, the software debugging is complicated, and the switching system has a large number of hardware, which is difficult, demanding, wide-ranging, and has long communication interruption throughout the network. Therefore, before upgrading the version, technical personnel and relevant experts must be carefully organized to carry out repeated demonstrations and formulate feasible implementation plans and emergency measures, make sure that the version is successfully upgraded once.

In daily life, the Internet access will certainly involve wireless switches, which provide users with exclusive point-to-point connections. data packets are only sent to the destination, so as to avoid a significant reduction in the bandwidth of all ports when the data volume is large, therefore, selecting a high-performance wireless switch saves a lot of trouble for future work.

When used for a star structure, it acts as the center node to enlarge the signal. The port does not share the bandwidth. If it is a 10 M switch, the bandwidth of each port is 10 M, each port has its own MAC address. The main functions of the switch include physical addressing, network topology, error verification, frame sequence, and traffic control.

At present, some high-end switches also have some new functions, such as support for VLAN Virtual LAN), support for Link aggregation, and even some have routing and firewall functions. In addition to connecting to the same type of network, a vswitch can also interconnect different types of networks, such as Ethernet and Fast Ethernet.

Nowadays, many vswitches can provide high-speed connection ports that support fast Ethernet or FDDI. These ports are used to connect other vswitches in the network or provide additional bandwidth for key servers with high bandwidth usage. It is a network device and has a part of the router function. It can decide where the received data is sent, and its speed is faster than that of the router.

Major differences between a wireless switch and a hub

From the above analysis, we can know that the main differences between a vswitch and a hub are divided into four aspects: OSI architecture, data transmission mode, bandwidth occupation mode, and transmission mode. The difference between the OSI architecture is that the hub belongs to the first layer of the OSI physical layer device, and the switch belongs to the second layer of the OSI data link layer device.

This means that the hub only synchronizes, scales up, and shaping data transmission, and cannot effectively process short frames and fragments in data transmission, the integrity and correctness of data transmission cannot be guaranteed. The switch can not only synchronize, zoom in, and shaping data transmission, but also filter short frames and fragments.

Differences in data transmission methods currently, 80% of LAN) is an Ethernet device that uses a HUB or Switch in a large amount. The LAN connected by a hub is called a shared LAN, and the LAN connected by a wireless switch is called a switched LAN.

Different ways of working. Let's talk about the sharing and exchange concepts in the network. For example, if a road with 10 lanes is not marked with a traffic route, a vehicle can only snatch or occupy a road in a disordered state, A vehicle that is prone to traffic jams and reverse driving will crash, reducing the traffic capacity.

In order to avoid the above situation, we need to mark the vehicle lines on the road to ensure that each vehicle does its own way and does not interfere with each other. A shared-bandwidth network is equivalent to an unordered state. When the number of data and users exceeds a certain limit, a collision or conflict will occur, leading to a decline in network performance.

The exchange network avoids the deficiency of the shared network. The exchange technology is to independently send each information packet from the port to the destination port based on the destination address of the transmitted information packet, it avoids collision with other ports and increases the actual throughput of the network.

The main problem with shared Ethernet is that all users share bandwidth. The actual available bandwidth of each user decreases with the increase of the number of users. This is because when the information is busy, multiple users may compete for one channel, while one channel only occupies one user at a certain time, therefore, a large number of monitoring waits often, resulting in jitters, stagnation, or distortion during signal transmission, seriously affecting network performance.

In switched Ethernet, a wireless switch provides a dedicated information channel for each user, unless two source ports attempt to send information to the same destination port at the same time, otherwise, the source port and the target port can communicate at the same time without conflict.

Working mechanism the working mechanism of different hubs is broadcast. No matter which port receives a packet, the packet is sent to all other ports in the form of broadcast, the NIC connected to these ports determines whether to process the information and leave the information for processing. Otherwise, the information is discarded, which may cause a broadcast storm, when the network is large, the network performance will be greatly affected.

According to its working status, the execution efficiency of the HUB is relatively low and the packet is sent to all ports.) poor security, all NICs can receive the packet, but the non-destination Nic discards the packet ). In addition, only one packet can be processed at a time, and a collision occurs when multiple ports appear at the same time. The packet is processed in serial mode and is not suitable for large network trunk.

1. Correct Interpretation and test of vswitch Port
2. Summarize the market status of high-end Switches
3. Focuses on core layer switch faults
4. PythonAndroid
5. Let's talk about the stacking of Ethernet switches.