Summary of core switch technologies

No matter what kind of equipment or environment it is difficult to avoid hacker and virus attacks, how can we immediately avoid the troubles caused by viruses on switches, therefore, the security protection capability of the network becomes the focus of user attention and cannot be ignored.

In the face of the challenge of network security, there are not many core switches without network management, and intelligent core switches will provide more comprehensive network protection with multiple security mechanisms. The Port-based traffic control function can effectively control network storms, ensure port security, and avoid data loss;

The application of the access control list (ACL) Technology ensures that network devices are not illegally accessed or attacked. The VLAN function is used to limit the intra-group traffic of broadcast domains and Intranet segments. These can be seen on the representative product D-Link DES-3226S In the Gigabit market. In addition, DES-3226S also fully supports 802.1x Standard, provides a leading user identity authentication mechanism, effectively reduces the probability of network intrusion.

Like security, the stability of the network is also crucial, especially for users in the financial, medical, energy and other industries. Poor network performance for a short period of time will bring immeasurable significant losses, only the failure of the edge switch affects hundreds of clients.

The loss caused by network instability has become a major killer of enterprise business development. Therefore, many switches have added redundant configurations. Chen qiyan, general manager of D-Link product department, introduced the redundant path function of the product in DES-3226S, which ensures that the failure of any core switch in the network will not affect the normal operation of the network.

In addition, this product can combine eight ports into a multi-link and load balancing aggregate bandwidth to provide failure-protected connections for key task servers and network centers, fully ensuring the stable operation of the network is a good way to expand bandwidth and build a high-quality network.

Currently, smart users are more rational when purchasing devices, pay more attention to ROI, and seek the best fit for purchase costs and network applications, therefore, "cost-effective" products have always been favored by consumers. In addition, brands mean quality assurance, technical assurance, and service assurance. Cisco, D-Link, and Huawei 3Com are all brands that are deeply trusted by users in the network equipment market.

Because the core switch is the backbone of the network, it has a high technical level, and its performance and efficacy directly determine the quality of the entire network, it is recommended that consumers choose brand equipment manufacturers with strong technical capabilities, considerate services, and good reputation while measuring the cost effectiveness based on their own needs.

The so-called sharing technology means that every workstation on a logical network is in the same network segment. The CSMA/CD mechanism is adopted in Ethernet. This conflict detection method ensures that only one site can be transmitted on the bus. If two sites attempt to access the bus and transmit data at the same time, this means that a "Conflict" occurs and both sites will be notified of an error. Then they are all rejected, and wait for a while for re-sending.

This mechanism is similar to the fact that many cars have snatched a narrow bridge. When the two cars attempt to mount the bridge at the same time, there is a "Conflict" between them. Both cars must exit, and then they start to rush again. When there are too many cars, such unordered competition will greatly reduce efficiency and cause traffic congestion.

The same is true for networks. When the number of users on the network is small, the traffic on the network is light, and there are fewer conflicts. In this case, the conflict detection method works better. When the traffic on the network increases, conflicts also increase, and the throughput of the inbound network will also decrease significantly. When traffic is high, the Workstation may be rejected again and again.

LAN switching technology is used to provide effective network segment division solutions for shared LAN. It enables each user to share the maximum bandwidth as much as possible. The exchange technology operates on the data link layer in the OSI Layer-7 network model.

Therefore, the switch forwards data packets based on the MACMedia Access Control Address (physical address). For the IP network protocol, it is transparent, that is, when the switch forwards data packets, if you do not know the IP address of the source machine and the host machine, you only need to know the physical address, that is, the MAC address.

During the operation, the switch will constantly collect data to create an address table of itself. This table is quite simple. It shows the port on which a MAC address is found, when the switch receives a TCP/IP packet, it checks the destination MAC address of the packet and its address table to determine the port from which the packet should be sent.

Because this process is relatively simple, and this feature is implemented by a brand new hardware-ASIC (Application Specific Integrated Circuit), the speed is quite fast, generally only a few dozen microseconds, the switch determines where an IP packet should be sent. It is worth mentioning that the switch should receive an unknown packet.

That is to say, if the destination MAC address cannot be found in the address table, the switch will "diffuse" the IP address packet, that is, it will be sent out from each port, the same is true when a vswitch processes a received broadcast packet. The weakness of a layer-2 switch is that it does not effectively process broadcast packets.

For example, when a core switch receives a broadcast packet sent from a TCP/IP workstation, it transmits the packet to all other ports, even if some ports are connected to an IPX or DECnet workstation. In this way, the bandwidth of non-TCP/IP nodes will be negatively affected.

Even if the same TCP/IP nodes have the same subnet as the workstation that sends the broadcast packet, then they will receive some network broadcasts irrelevant to them for no reason, and the efficiency of the entire network will be greatly reduced. LAN switching devices have emerged since 1990s. From the perspective of network switching products, there are roughly three types of switching products: port switching, frame switching, and metadata switching.

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