Seven golden laws of switch purchasing points

Seven golden laws of switch purchasing points. When purchasing a switch, in addition to looking at the brand, you should also choose according to the following points. Although vswitches are currently on the desktop, some of the more advanced switches are generally only available in larger LAN.

In addition, the mystery of switches has always led to the decision of sellers in most cases. There are many things to pay attention to when purchasing a vswitch. It is no longer determined by just a few simple parameters like a hub. The following lists the main considerations when purchasing a vswitch.

Switch purchasing key: Forwarding Method

The packet forwarding method has been introduced earlier. It can be divided into "pass-through forwarding" and "pass-through forwarding ". Because different forwarding methods are suitable for different network environments, you should make appropriate choices based on your own needs. Because the pass-through method only checks the packet header and does not need to be stored, the cut-in method has the advantage of low latency and fast switching speed. At the same time, it has three disadvantages described above.

The storage and forwarding method is large in data processing latency. However, it can detect errors of data packets entering the vswitch and supports switching between input and output ports at different speeds to effectively improve network performance. At the same time, this switching mode supports switching between ports at different speeds to ensure collaboration between high-speed ports and low-speed ports.

Low-end switches usually have only one forwarding mode, storage and forwarding mode, or pass-through mode. Generally, only mid-and high-end products have two forwarding modes, and have the smart conversion function, you can automatically switch the forwarding mode based on the communication conditions. Generally, if the network does not require a high data transmission rate, you can select a storage-based forwarding switch. If the network requires a high data transmission rate, you can select a direct-through forwarding switch.

Switch purchase highlights: latency

The delay Latency of A vswitch, also known as the delay time, refers to the interval between the time the vswitch receives the data packet and the time it starts to send the data packet to the destination port. This is mainly affected by factors such as the adopted forwarding technology. The smaller the latency, the faster the data transmission rate, and the higher the network efficiency. Especially for Multimedia Networks, large data latency often leads to short-term multimedia interruptions. Therefore, the shorter the delay time of the switch, the better, vswitches with lower latency are more expensive.

Switch purchasing key: Management Function

Management of vswitches) refers to how a vswitch controls the user's access to the vswitch, and how manageable the system administrator is to the vswitch through software. If you need the above configuration and management, You must select a network-type switch. Otherwise, you only need to select a non-Network-type switch.

Currently, almost all medium and high-end switches can be managed by network management. Generally, all manufacturers will provide a copy of the switch management software developed by the company at random. All switches can be managed by third-party management software. Low-end switches do not have network management functions. They are "Dummies". They only need to connect to the power supply and plug in the network cable to work normally. The cost of network management is much higher.

Switch purchase key: MAC address count

As described above, we know that a vswitch can send data packets directly to the target node, instead of transmitting data packets to all nodes in broadcast mode like a hub, the most critical technology is that the switch can identify the nic mac address of nodes connected to the network to form a MAC address table.

This MAC address table is stored in the cache of the vswitch, and these addresses are remembered so that when you need to send data to the destination address, the switch can find the node location of the MAC address in the MAC address table, and then send it directly to the node.

However, each port of a vswitch of different grades can support different MAC numbers. Each port of the vswitch requires sufficient cache to remember these MAC addresses. Therefore, the size of the Buffer capacity determines the number of MAC addresses that the vswitch can remember.

Generally, a vswitch can only remember 1024 MAC addresses, while a general vswitch can do this. Therefore, if the network size is not large, this parameter does not need to be considered too much. Of course, the more high-end switches can remember, the more MAC addresses there will be, depending on the size of the connected network.

Switch purchase key: backboard bandwidth

More and more M switching to the desktop solutions are aimed at VOD. If you have the same requirement, you should pay attention to the switch backboard bandwidth when purchasing a switch. Of course, the wider the bandwidth, the better, it provides high-speed switching for your switches under high loads. Because communication between all ports needs to be completed through the backplane, the bandwidth provided by the backplane becomes the total bandwidth for concurrent communication between ports.

The larger the bandwidth, the higher the available bandwidth that can be provided to each communication port, the faster the data exchange speed. The smaller the bandwidth, the smaller the available bandwidth that can be provided to each communication port, the slower the data exchange speed. Therefore, when the port bandwidth and delay time are the same, the larger the backboard bandwidth, the faster the transmission rate of the switch.

Switch purchasing key: Port

A vswitch has the same port bandwidth as a hub, but the bandwidth mentioned here is different from the port bandwidth of a hub, because the port bandwidth mentioned in the vswitch is exclusive, the bandwidth of the port on the hub is shared. Currently, the port bandwidth of A vswitch mainly includes 10 M, M, and M, but these three bandwidths have different combinations to meet the needs of different types of networks. The most common combinations include n * 100 M + m * 10 M, n * 10/100 M, n * 1000 M + m * M, and n * m.

Switch purchasing key: Optical Fiber Solution

The last point is the selection of optical fiber. If you must select optical fiber in the cabling, you can select the following three schemes in your switch Selection Scheme: one is a switch with Optical Fiber interfaces; in addition, you can add an optical fiber module to a switch in the module structure. The last one is to add an optical fiber and a twisted pair forwarder.

The first solution has the best performance, but is not flexible enough and expensive. The second solution has strong flexible configuration capability and good performance, but is the most expensive. The last solution is the cheapest, however, performance is greatly affected. Now, we will briefly introduce the basic technologies and precautions for the purchase of vswitches. The next article will officially introduce another important aspect of vswitches, that is, the configuration of vswitches, this is very important for network administrators and must be mastered. Stay tuned!