The switch cascade can be defined as two or more switches connected in a certain way, according to the need, multiple switches can be cascaded in a variety of ways. In large local area networks such as campus network (campus network), multiple switches in accordance with the performance and use of the general form of bus, tree or star cascade structure.
Switch stacking means that more than one switch is combined to work together to provide as many ports as possible in a limited space. Multiple switches are stacked to form a stacking unit. The stackable switch performance has a "maximum stackable number" parameter, which is the maximum number of switches that can be stacked in a stacking unit, representing the maximum port density that can be provided in a stacking unit. Not all switches support stacking, depending on the brand of the switch, whether the model supports stacking, and also requires specialized stacking and stacking modules. Finally, note that the switches in the same stack must be the same brand.
Fiber switch
1, fiber switch is a high-speed network transmission relay equipment, it is more common than the use of fiber optic cable as a transmission medium.
2, the advantages of optical fiber transmission is fast, anti-interference ability.
3, fiber optic Ethernet switch is a high-performance management of the two-tier fiber-optic Ethernet access switch. Users can choose all-optical port configuration or optical port hybrid configuration, access to fiber-optic media optional single-mode fiber or multi-mode fiber. The switch can support network remote management and local management to achieve the port working status of the monitoring and switch settings. Fiber ports are particularly suitable for information points Access distance beyond the five categories of access distance, the need for anti-electromagnetic interference and the need for confidential communications and other occasions applicable areas include: residential FTTH broadband access network; enterprise high-speed fiber LAN; high reliability industrial distribution Control system (DCS); optical fiber digital video surveillance network; hospital high-speed optical fiber local area network; campus network.
Switch Protocol Link Hierarchy:
The first layer of physical layer:
The physical layer is the basis for data transmission, completely by the hardware into the physical layer constitutes a data transmission channel. The physical layer transfers only the bit stream, which specifies the mechanical, electrical characteristics of the channel and the interface between the next layer. I often use the modem (MODENM) and hub (HUB) are physical layer of the network equipment.
Layer 2 data link layer:
The data link layer will provide data link control and error checking functions that will make unreliable physical links a reliable data link. Data link layer communication is based on Zhen, we are familiar with the exchange technology that is through the switch to achieve the exchange of technology, the traditional switch (Layer 2 switch) is the data link layer of the typical network equipment, the predecessor of the Bridge, bridge work in the second layer of the network, one of its role is to isolate the network broadcast storm. The switch can only connect to the same subnet computer, if the computer's IP address is not in the same subnet can only be achieved by the switch Communication, but also rely on the third layer of the router.
Layer 3 network layer:
The network layer can be said to be an important layer in the OSI model. It plays an important role in the communication. As mentioned above, it is responsible for the communication between subnets. The well-known TCP / IP protocol is the protocol in the network layer. The communication between the two subnets takes the router with the routing function. Sending a packet from a subnet If you want to reach a computer node in another subnet, it is necessary to calculate the path of the transmission through the router.
Aggregation layer, higher than the access layer switch, to Gigabit speed, and to have the upper link, the cascade interface should also be gigabit, or else how to connect to the core switch.
The core layer, the layer of the switch requires a very high performance is poor, the whole system will be paralyzed. The main role is the convergence of the exchange switch, the video surveillance platform, the best use of three full Gigabit or 10 Gigabit switches, such as the number of the entire camera more than 150 best with 10 Gigabit, insurance.