The old are strong, the heart is white, the poor, the strong, the heart is not blue. - don wang bo
Exchange knowledge
Basic knowledge of switches
The emergence of many new clit/server applications and multimedia technologies has led to traditional sharing
The presence of lan switches was also facilitated by the fact that networks were far from meeting the requirements. 1. Definition of switches
The lan switch has many ports, each of which has its own special bandwidth and can connect to different segments of the network。
Communications between the various ports of the exchange are simultaneous and parallel, which significantly increases the amount of information being swallowed up. For further
To improve performance, each port can also connect to only one device。
Lan switches typically have one or more to connect switches or high-end servers
High-speed ports such as 100m ethernet port, fddi port or 155matm port to ensure the entire network
The transmission performance. 2. Features of switches
Users sharing local area networks through hubs are not only sharing bandwidth but also competing bandwidth. Could be due to individual users
More bandwidth is needed, resulting in a relative reduction in the bandwidth available to other users, and even being forced to wait, thus delaying access
Letter and information processing. A large shared local area network (lan) user could be used using the switch's network micro-sequence technology min
Make many stand-alone web segments, reduce the number of competing bandwidth users and increase the bandwidth available to each user, thereby easing sharing
Network congestion. Since the ability of switches to move information quickly and directly to their destination can significantly increase speed and bandwidth
It protects users from previous investments in media and provides good scalability, so the switch is not just a bridge
An ideal alternative, and an ideal alternative for a hub。
And those who set great things before them, not only are they superior, but they are steadfast. — susie
Switches have improved performance in the following ways compared to bridges and hubs: (1) by supporting parallel communications
The information throughput of the switch was increased。
(2) split users of a traditional large local area network into working groups, with each port connected to one device or company
Another working group was established to effectively address crowding. This method is known as microsynthesis
(a) technology。
(3) the emergence of virtuailan technology has brought greater inspiration to the use and management of switches
Active. We'll talk about the virtual network later。
(4) port density is comparable to that of a hub, and the average network system has one or more services
The machines, and most of them are ordinary customer machines. Clients need access to servers, which leads to servers
Communication and transactional capabilities are key to the performance of the entire network。
Switches will be improved mainly by increasing the rate of access to servers and the size of the corresponding frame buffer
The performance of a network to meet user requirements. Some high-end switches use full- and double-work technology to further improve the end
The bandwidth of the mouth. Most of the old network equipment used to work half-hourly when a host sent the data. Package
, it cannot receive the package, and when it is received, it cannot send the package. Due to full adoption
Double technology, i. E. The host can receive the package while sending the package, and the normal 10m port can change
In a 20m port, a normal 100m port becomes a 200m port, which further enhances information swallowing
Spit. 3. The working principles of the switch
The traditional switch is essentially a multi-port bridge with traffic control capability, the traditional (second-tier) switch。
Woe to the heavens before, and joy after. - fan is drowning
The introduction of routing technology into the switch will complete the network-level route selection, which is called a three-storey exchange
Show. Switches (second floor exchange) work principle switches, like internet bridges, are networked devices working on the chain level
Each port is connected to a lan or a high-performance website or server
It is possible to learn about equipment connections at each port through self-learning. All ports are controlled by specialized processors and are controlled by
Transmit information over the control management bus. At the same time, centralized management could be carried out using dedicated web-based software. Besides, hand over
In order to improve the speed and efficiency of data exchange, the switch generally supports multiple approaches. (1) storage and forwarding:
All conventional bridges use this method. They're going to finish receiving the frame before they send the frame to other ports
Fully stored in an internal memory, which is checked and sent to another port, so that the delay is equal to the receipt of a complete
The total of data frames and processing times. If the cascade is long, it can cause serious performance problems, but this method
You can filter the wrong data frame. (2) entry:
It only checks the target address of the data frame, which makes it almost instantaneous and thus large
Big drop delay。
The disadvantage is that the wrong frame is also passed out. If the error frame is less likely, the entry method may be used
High transmission speed. In cases where there is a high probability of a wrong frame, storage forwarding/reduced
Wrong frame's retransmitting. 4. Switch configuration
We will now take the example of the catlystl 900 switch from cisco to describe the general configuration of the switch。
For a new catlystl9000 switch, use of its default configuration will be able to work. Because it's kind of..
Hardware devices for loading software in flashmemory, which, when charged, first perform a series of self-inspection checks for all
And the heaven will be sent down upon the people of the world, and they will suffer their hearts, their bones and their bodies, and their skins, and their bodies will be empty, and they will wander about their deeds. - monko
After the port has been tested, the switch is in working condition. It's empty. It can learn from itself
To check the equipment connections at each port and record the mac address of the device in the exchange form when information is exchanged
The switch is then used for data forwarding on the basis of the exchange form. But to facilitate its network management
Catlyst1900 has its own mac address so that it can be assigned an ip address and shield code。
Network administrators are required to access a terminal or a simulation terminal through a chain of exchanges in order to assign an ip address to it
